According to forum participant ontwerper from Moscow, it’s not that difficult to do on your own. He cites well-known and little-known considerations for their manufacture as arguments. In his opinion, making ceilings with your own hands is beneficial for several reasons:

1. Availability of technologies and materials;
2. Convenience and practicality from architectural and engineering points of view;
3. Such floors are durable, fireproof and have noise-insulating qualities;
4. Financial feasibility.

Monolithic works

Before pouring concrete, ontwerper advises to carefully think through the entire process and, first of all, order concrete from the factory. It is better than homemade - there is control over the quality and quantity of fillers that improve the concrete and prevent it from delaminating for a long time. The composition must consist of heavy aggregates, have a strength class of B20-B30 (M250-M400), and frost resistance of F50.

Don’t be lazy and check the documents for the release parameters, grade and time until the concrete sets.

If you need to supply concrete to the second, third floor or over a long distance, you will not be able to do this without a concrete pump, and rolling concrete with shovels along endless gutters is a very difficult and inconvenient task.

IN winter time concrete can be ordered with anti-frost additives, taking into account that additives usually increase the time of strength gain, some of them provoke corrosion of reinforcement, but this is acceptable if the additive is factory-made.

ontwerper prefers not to carry out construction in winter, and does not recommend it to you. As a last resort, do not prepare the solution yourself; use industrial concrete.

Installation of formwork

The main purpose of formwork is to withstand the mass of freshly poured concrete and not deform. To calculate the strength you need to know that one 20 centimeter layer of concrete mixture presses on square meter formwork with a force of 500 kg, to this you need to add the pressure of the mixture when it falls from a hose, and you will understand that all structural elements must be reliable.

To make it, ontwerper recommends using 18-20mm laminated (coated) or plain plywood (but it sticks more strongly). For beams, crossbars and formwork posts, timber with a thickness of at least 100x100 mm should be used.
After assembling it, it is necessary to check the horizontalness of all structures. Otherwise, you will waste a lot of time and money fixing errors in the future.

Reinforcement

The lower one is along the span, the lower one is across the span, the upper one is across the span, the upper one is along the span.

span– the distance between the supporting walls (for a rectangular slab on the short side). The lowest row is placed on plastic crackers specially designed for this; their height is 25-30mm. The top row overlaps it across and is knitted with wire at all intersections.

Then the next step is the installation of a mesh separator - parts made of reinforcement with a certain pitch, it can be done at will. On the dividers - knit the top one across, - knit the top one along it, - knit with wire at all intersections. The top point of the frame (top of the upper rod) should be 25-30 mm below the top edge of the formwork wall, or the thickness of the concrete is 25-30 mm above the top reinforcement.

After the reinforcement is completed, the frame should be a rigid structure that should not move when concrete is poured from the pump. Before pouring, check that the pitch and diameter of the reinforcement correspond to the design.

Pouring concrete

After all the preparation, you need to take and distribute the concrete over the entire area and vibrate it. It is best to fill the slab entirely at one time; if this is not possible, place cuts - intermediate walls inside the formwork contour that limit concreting. They are made from steel mesh with a cell size of 8-10 mm, installing it vertically and attaching it to the frame reinforcement. Under no circumstances should you make cuts in the middle of the span and do not make them from boards, PPS.

Curing

After pouring the slab, you need to cover it to prevent precipitation from entering, and constantly water the outer surface to keep it moist. After about a month, you can remove the formwork, and in case of emergency, this can be done no earlier than after a week and only remove the panels. To do this, you need to carefully remove the shield and back up the slab with a stand. The racks support the stove until it is completely ready, about a month.

Strength of monolithic floor: calculation

It comes down to comparing two factors:

1. Forces acting in the slab;
2. The strength of its reinforced sections.

The first must be less than the second.

Walls on monolithic slab floors: calculating loads

Let us calculate the constant loads on a monolithic floor slab.

Self-weight of a monolithic floor slab with a load safety factor of 2.5 t/m3 x 1.2 = 2.75 t/m3.
- For slab 200mm - 550kg/m3

Own weight of a floor with a thickness of 50mm-100mm – screed – 2.2t/m2 x 1.2= 2.64t/m3
- for floor 50mm - 110kg/m3

Bring partitions made of bricks measuring 120mm to the area of ​​the slab. The weight of 1 linear meter of a partition with a height of 3m is 0.12m x 1.2x1.8 t/m3 x 3m = 0.78t/m, with a step of partitions 4m long it turns out to be approximately 0.78/4 = 0.2t/m2. Thus, the reduced weight of the partitions = 300 kg/m2.

Payload for the 1st group of limit states (strength) 150 kg/m3 - housing, taking into account the reliability factor of 1.3, we will accept. Temporary 150x1.3= 195kg/m2.

Full design load per slab - 550+110+300+195=1150kg/m2. For sketch calculations we will accept a load of - 1.2t/m2.

Determination of moment forces in loaded sections

Bending moments determine 95% of the reinforcement of flexural slabs. Loaded sections are the middle of the span, in other words, the center of the slab.

Bending moments in a square slab of reasonable thickness, hingedly supported - not restrained along the contour (on brick walls) for each of directions X,Y can be roughly defined as Mx=My=ql^2/23. You can get some values ​​for special cases.

• Slab in plan 6x6m - Mx=My= 1.9tm;
• Slab in plan 5x5m - Mx=My= 1.3tm;
• The slab is 4x4m in plan - Mx=My= 0.8tm.

These are forces that act both along and across the slab, so you need to check the strength of two mutually perpendicular sections.

Checking strength to the longitudinal axis

When checking the strength to the longitudinal axis of the section by bending moment (let the moment be positive, i.e. belly down), the section has compressed concrete on top and stretched reinforcement on the bottom. They form a power couple that perceives the momentary force coming to it.

Determination of effort in this pair

The height of the pair can be roughly determined as 0.8h, where h is the height of the slab section. We define the force in the reinforcement as Nx(y)=Mx(y)/(0.8h). We get a representation of the 1 m width of the slab section.

• Slab in plan 6x6m -Nx(y)= 11.9t;
• Slab in plan 5x5m - Mx=My= 8.2t;
• The slab is 4x4m in plan - Mx=My= 5t.

For these efforts, select reinforcement of class A-III (A400) - a periodic profile. The calculated tensile strength of the reinforcement is R=3600kg/cm2. cross-sectional area of ​​the reinforcing bar with diameter Ф8=0.5cm2, Ф12=1.13cm2, Ф16=2.01cm2, Ф20=3.14cm2.

The bearing capacity of the rod is equal to Nst=Ast*R Ф8=1.8t, Ф12=4.07t, Ф16=7.24t, Ф20=11.3t. From here you can obtain the required reinforcement spacing. Step = Nst/ Nx(y)

• Slab in plan 6x6m for F12 reinforcement Step=4.07t/11.9t=34cm;
• Slab in plan 5x5m - for F8 reinforcement Step = 1.8/ 8.2 = 22cm;
• Slab in plan 4x4m - Ф8 Step=1.8/5=36cm.

This is strength reinforcement in each of the X and Y directions, i.e. a square grid of rods in the tensile zone of concrete.

In addition to strength, it is necessary to reduce the formation of cracks. For slabs of houses and residential premises with a span of up to 6 m, 200 mm thick, supported along the contour (i.e. on four sides) at any ratio a/b, you can take lower working reinforcement from A III rods in two directions with a step of 200x200 with a diameter of 12 mm, upper ( constructive) - the same from F8, thinner and smaller should not be.

All this is a special case of the general approach, demonstrating the specifics of the task, but to implement it it is necessary to look deeper and turn to specialists.

Posted by FORUMHOUSE member ontwerper.

Editor: Adamov Roman

If the article does not answer your question, ask it in the comments. I will try to answer as quickly as possible.

I wish you success in your work.

Acceptable amount is from 10 rubles. up to 15,000 rub.

217 comments

Hello. I read an article about floor slabs. I took note of a lot.
I'm very interested in the recipe for the concrete used to pour the slab. You have to do this yourself.
I can’t decide whether to order (concrete + delivery + tape feed = expensive), or do it myself (production time + difficulty of supply 2nd floor + strength of self-made concrete =?). Crushed stone 5-20, cement 500, washed sand - coarse grain, concrete mixer, small lift with zl. winch available.
I would appreciate your answer. Thank you in advance.

Hello. As for kneading or buying, of course, everyone has their own arguments. For example, I have a problem with access roads and hiring workers. strength, for quickly producing a large volume of solution, the slab is at the level of the second floor. There is no tape either. But I have mine for 100 kg. It’s slower than using a tape; you won’t have time to lift a lot of concrete, so I kneaded it myself. And actually, this is the easiest moment in making a slab. It’s a hassle with formwork and reinforcement, but mixing and pouring is not a problem.

About the “secret of concrete”. He is. The proportions are usual: 35-40 shovels of ASG per bag of cement. Cement 400. But cement also has such an indicator as a strength class. It should be 42.5. I used Mordovian cement.

And the most important thing is the additive Sika ViscoCrete 5-600 N PL. The thing is not cheap, but its consumption is so small (I don’t remember exactly) that it’s worth the price. Concrete with this additive turns out to be so strong that it will give a head start to factory-made concrete. You don't even need to vibrate. And with such strength it breathes and does not allow moisture to pass through. I’ll write another article about her. Phenomenal stuff.

As for the filler, don't worry about it. Ordinary PGS. Enriched sand would probably work too, but I haven’t tried it.

Good afternoon.
They are renting out a monolithic brick house, and the end of the monolithic slab on which the wall (and the ceiling) rests is all uneven and roughly stained with mortar. how this can affect freezing, and then also spalling of cement.
Thank you
Sincerely, Igor

Of course, it wouldn’t be bad to see what was there and how it was, but as long as I worked at the monolit construction, I never saw uneven and crumbling ends of the interfloor ceilings. True, the organization was Yugoslavian, and they simply quit work if they did not have the materials necessary for high-quality execution of one or another part of the building.

I won’t tell you exactly what you have there, but I will advise: don’t hesitate to ask the builders questions. Ask persistently about everything that worries you, and don’t let them get off with general answers like Everything is fine. That’s how it’s supposed to be and put pressure on the prof. terms.

Please check. More Why. Don't be afraid to look like a fool. On the contrary, turn on the fool and ask, and better yet, ask the hard workers. Construction bosses are masters of working with their tongues and resolving situations. Don't make any statements, just questions. If they can’t answer sensibly, then they’ve screwed up.

If possible, send photos, we'll see.

Hello! I am going to build a house using the same technology, only I have the idea of ​​using the same expanded clay instead of gravel in concrete for monolithic floors. After all, it has much better sound insulation and thermal insulation, and the ceiling itself will be lighter! Please tell me, because you probably had the same idea, why didn’t you resort to such technology? Thank you.

To be honest, Egor, such an idea never occurred to me. Somehow it became ingrained that the ceiling should be concrete. After all, I also worked at a monolithic construction site, so if the ceiling means concrete. Noise and thermal insulation come later, but the base is concrete.

Will expanded clay concrete withstand the floor? In its pure form it will not stand even one meter per meter. I've worked with him enough and I can say that. Even if you knead it more abruptly.
But if you assemble the ceiling in the form of a lattice, say from a channel, or put a channel every 60 cm, and pour expanded clay concrete between them, then perhaps it will work.

True, there are still questions that arise about how this design will behave, but only those who have done it can answer them. Assumptions won't work.

Yes, indeed, I think you are absolutely right. Bad idea. Thank you.

Hello, tell me, did you do it? monolithic ceiling thickness 12 cm, distance 5x8 when walking, vibration. Because of the fear of falling down, they made a reinforcement (pulled it together) with a 14-channel channel from the bottom and from the top, and they screwed up. At such a distance of 8 meters 4 pieces were placed. My husband wants to put more reinforcement between the channels (weld it to the channel) and fill it with concrete. We also want to make supports-pillars from below. The result will be a slab over 30 cm. Isn’t this a big load on the foundation? Can it be strengthened somehow differently? Thank you.

12 cm is of course not enough for such an area, well, once it’s done, it’s done. The question is what to do next.

Since the total is 30, it means you have 18 channels. The span between them is 1.6 m. This in itself is a strong overlap. Moreover, there are pillars below. There will probably be too much concrete. Fill with expanded clay concrete. And light, and no matter what, but warm and sound insulation.

Thank you. What if you lay a warm floor between the channels? Is it possible to do this?

The question is certainly interesting. In any case, I have never done this, and I have not seen anyone do it. But I think in principle it is possible. I would only lay the TP on top of the channel, and definitely on thermal insulation, such as penofol cork or penoflex. Better, of course, is a cork mat. Then the channels will not heat up and expand. Metal expands more when heated than concrete. Only the thickness of the screed will increase further.

Hello. I have a question, a monolithic floor slab 15cm thick. 8.4×5.6, in the center there is a half-brick partition, the first row is 1 cm away from the slab. The slab sank a little. Isn’t this very scary if you still need to fill in the screeds and Plaster the second floor, thereby further loading the floor slab?

It is difficult to answer such a question so simply. We need to understand why and how the slab sank. Are there any cracks along it? Why did the partition hang? This means there is no pressure on the slab, and it sank under its own weight. But how did it sag, did it bend or something? In general, you need to look locally.

If the reinforcement is done correctly and the quality of the concrete is not lower than M200, then at this thickness it should hold without problems.

Hello. Please tell me what can cause the facing brick to crack, crack 1-2 mm. in the corners of the house. house 15×15.2 floors. foundation monolithic slab 35 cm thick. double reinforcement 20×20, in the corners and in the center the piles were poured together with a slab. the floor slab is also a monolith 15 cm thick. reinforcement 20×20 12 reinforcement. cracking strictly vertical brick floor from the corner. where below, where above. close to groundwater 1.5 m. the house was built in the summer. sand cushion 20 cm. thrombosed, crushed stone bedding 15 cm .also rammed. After the new year, the heating was turned on. What could it be? uneven shrinkage of the slab, or because the house began to warm up?

Of course, I won’t say exactly why the namesake cracked, but it’s not because of warming up. And here is some food for thought. For 8 years I served one cottage built on the banks of the Kama. The situation is very similar to yours. The house was built by Yugoslavs. Everything is according to the drawings and in accordance with all possible construction requirements. Also on a monolithic slab, albeit 40 cm, with a monolithic frame and not two, but three floors.

They didn’t turn to geologists, but they should have.

It started cracking in the first off-season after construction, just have time to repair it, and it’s still cracking. Construction luminaries came and everyone agreed on one thing - the groundwater is close (1.2 - 1.5 m) and its level changes depending on the water level in the Kama. As a result, the soil and the slab lying on it are mobile, which is why cracks appear.

The second villa was built on stilts, already according to the calculations of geologists, but so far only a monolithic frame. Let's see what happens to her.

Master, please give me advice on how to pour the interfloor slab yourself without helpers. A 10x12 house can lay the channel in parts as you advised after 60 cm, and pour it in strips and at the end thin common layer like a type of screed. After all, they lay down the slabs with a crane and then smooth them out with a screed or something. I don’t have access roads and there’s no one to hire; there are only drunks all around, and I’m not in a hurry to fill in strips, so what can you advise me on what to do. Thanks in advance for your answer.

Yes, Leka, the situation is just like mine. And it’s impossible for the crane to arrive, and there’s trouble with the assistants, all they can do is beg for money for a hangover.

In general, I’ll add a little information to what’s in the post, because after this stove at my place, I made another one at my brother’s. They poured it together. The largest floor area without supporting walls was 40 square meters. those. 5 x 8. The working conditions were more difficult, so we couldn’t fill it in one day. And they didn’t make it in two. We finished only on the third day.

The formwork and reinforcement were done as I described in the article, and they were filled with transverse strips. In the evening, the fresh filling was completely covered with film, and continued early in the morning.

The concrete did not have time to set overnight and the fresh concrete either bonded well or aggregated with yesterday’s concrete. So they filled it in, covered everything with film and removed it only after about a month.

Then, after two weeks, they began to raise the second floor, that is, to fully load the slab. And they put a half-brick partition on it, and a fireplace on the edge, but still on the stove.

Now the house is almost ready and there are no problems. The thickness of the slab is 12 - 13 cm. The filler is ASG. The concrete was made with the additive Sika ViscoCrete 5-600 N PL.

Now about the slab with channels. This is what my colleague did. Just today I asked you in detail especially for you. Channel 14, after 60 - 70 cm, a 50 x 50 mm block was attached to the channel area from below, and formwork was connected to this block from below.

Reinforcement d10 is laid on the channel flanges every 20 cm, then a second layer is placed across it every 20 cm to form a mesh. Then all this is filled with expanded clay concrete along the top flange of the channel.

After the expanded clay concrete has dried and the formwork has been dismantled, the bars from the bottom flange are removed and the remaining seam is sealed with mortar.

Then a screed was made along the top and tiles were laid, but without TP. Noah I think that it is possible to do TP. It is unlikely that it will heat the channel from below to such a state that cracks will appear. Well, the film one certainly won’t heat up.

That's about it.

Master, I wildly apologize for the late reading, I was on a business trip, thank you very much for the information, if only there were more adequate information on the forums normal people people like you Master, otherwise there are only brawlers, boors, etc. Inadequate people who think of themselves as devils. As soon as a normal person talks about his construction project or shares a little experience, he is immediately dropped below the plinth, etc. Once again, thank you very much for the advice. With uv. Leka.

Please. It's not a pity. That's why I made the site, to share. And on the forums, I think, 90% of marketers are sitters and not hard workers. Their task is to crap everything around him, so that he is left alone in a white shirtfront, and so that the client comes to him. A vile profession is a marketer.

Good day, I really liked the article I read!!! Could you please tell me, I am going to cast a monolithic slab on a 7x9 T-shaped strip foundation, 30cm wide in the middle, 24cm, the distance inside to the middle is 3m. I am going to reinforce the “slab” with F12 on the bottom and F10 on top with a thickness of 18-20 cm. Will such a slab withstand a passenger car?

Very interesting question Andrey. Don't know how to answer. Both Matiz passenger car and Ford F650 passenger car. One weighs 500 kg, the other 10 tons. This is the first task. Well, the fact that the footing is 7x9 and 30cm wide is understandable, but what about 24 in the middle? And the distance is 3 m to the middle. The middle of what? Neither seven nor nine are suitable.
What's under the stove? Ground or basement?
The purpose of this article is to show HOW you can make a floor slab. The execution technique, so to speak, and the thickness and reinforcement were approximately calculated for me by a specialist from Sika, since I came to them for an additive (somewhere here in the comments I already told about it and gave the markings). And then there’s my fear and risk, and the experience gained.
As for your situation, if you think about it, the slab on the ground won’t go anywhere, even if you drive a Kamaz, but above the basement, you can easily make a support in the form of partitions in the basement to calm your soul.
I have a smaller and thinner stove. The largest area without supporting partitions below is 7x5, thickness 12-15 cm and only 10-gauge reinforcement. I can say for sure about my stove that it can easily withstand my Niva.

what is PGS

And is it possible to make an overlap between floors with the addition of expanded clay rather than crushed stone, proportions? And also - will it probably be a less durable floor? Is it worth making such a ceiling (the walls of the first floor are made of aerated concrete)?

Hello Marta. You can also make the floor from expanded clay, but in this case the technology will be completely different, using channels and a different method of reinforcement.

If the walls of the first floor are only made of aerated concrete, without a reinforcing frame, then is it worth making a second floor?

PGS - sand and gravel mixture.

Good afternoon!!! We are planning to pour a monolithic floor between the first and second floors, the size of the house is 12 by 10 m. There is a load-bearing wall in the middle, tell me, will 14 reinforcement with a pitch of 20 by 20 be enough and the resulting floor thickness will be 260 mm? We plan to lay the reinforcement in two layers. Thank you

Of course there will be quite respected Violetta. It will be possible to safely drive a KamAZ truck loaded with crushed stone onto your ceiling. For example, I have 10-gauge reinforcement and a slab thickness of 150 mm. (this is in the article), and the span between the load-bearing walls is even wider in width than yours (if you subtract the thickness of the walls). The length is really shorter, but nevertheless, in monolith construction (where I was stupid at one time to work as a reinforcement maker, although it was useful) for interfloor ceilings, the spans of which between the load-bearing walls are greater than yours, 12 cm reinforcement is used and a slab thickness of 20 cm, and this same high-rise building.

So be calm and good luck with your construction.

P.S. There is my answer in the comments, which mentions the Sika additive that I used. I highly recommend it for floor slabs.

Good afternoon, dear Master. I am building a garage 7 x 10 meters. First, we will pour a tape along the perimeter 400 mm wide and 1 m deep onto a backfill of crushed stone and sand. Then, on the tape and adding crushed stone and sand, we will pour a slab with a thickness of 200 mm and two-layer reinforcement with 12 mm reinforcement and a 200 mm cell. Next, the walls are made of expanded clay concrete blocks the width of a block and a height of 2.5 m. And the roof is on wooden frame. Question. Will the stove support a machine weighing 2 tons?
Thank you for your responses.

Oddly enough, my garage floor is made exactly the same way. The tape is a meter long, the slab is actually thicker, about 25-30. Everything is on a bed of crushed stone and sand. The reinforcement is thinner - 10, and the size is smaller - 6 x 9. It can support one car (1.6t) and a second (2t), and both at once. I'm going to cover the floor with breccia, and I'm not afraid that it will crack.

Greetings master. This is a question, I am building a box for myself. 8 pillars height 4.5 meters. lower area 119 sq.m, upper 157 sq.m. Do I need to connect the glasses of the pillars below with crossbars if the bottom slab is not monolithic with 8 pillars. purpose the bottom slab is a concrete floor. In this case, crossbars are needed or not. And in general, what is cheaper to make at the bottom - crossbars or a monolithic platform with pillars in a bundle. AND THE SECOND QUESTION: the top slab is 200 mm thick and has an area of ​​157 sq. m, I want to fill it myself. Enough Is it 0.5 cubic meters of concrete mixer for this adventure? I will need about 30 cubic meters of concrete for the top slab. Will I have time to pour everything so that the bond in the concrete does not turn out in pieces? The concrete mixer is made of pipe. Maybe a cubic concrete mixer is better. Or is it better to order ready-made concrete with a pump? I just want Saves money. Bottom plate 17x7 meters

Good evening. Without knowing the nuances of your idea, it’s difficult to give advice. Well, since there is a glass, isn’t it true that the pillars are metal? This means that the glass with the platform is tightly attached. Or is it not such a design? I just won’t drive in straight away. Well, actually, a reinforced monolithic slab combined with a reinforced concrete pillar is probably best. It’s not for nothing that residential high-rise buildings are built according to this scheme. There, the cost and reliability of the design are taken into account.

Now for the second one. Half a cube is certainly a beast. That's more than a ton per batch. But more than 30 cubic meters is also not hala bala. My son and I were at the limit of our strength, in 14 hours, with (100 kg) we poured 4 cubes at a time. The mixer is of course smaller - 0.180. Those. you have one batch, we did 3, but the main time is raising, pouring, leveling. Nevertheless, you can already roughly estimate how much capacity and people are needed to fill 30 cubic meters in 14 hours. And the concrete in the mixer is kneaded quickly. Almost in the process of loading.

Well, with a bit of adventurism, you can take risks. If only the people had the strength to work like an automaton. Two for loading, mixing, unloading, one for the crane, one for leveling, and three or four for shuttle work. Well, even transferring 75-80 tons per day is a question.

Hello. Please tell me, they made a monolithic floor for me, 18 cm, 12-reinforcement in 2 tiers, but it rarely lies about 40x40 cm,
Between the tiers of reinforcement there is a 6mm mesh (10x10 cm) spans 6x6 meters.
In one room I’m now putting up a wall that will serve as a support, but in another, unfortunately, it’s not possible.
So I’m wondering how bad my situation is?

Why is it impossible? What happened there?

according to the design there should not be a wall there, but there is less concrete there, because there is a second light and it seems that not everything is deplorable

I didn't quite understand what second light was. But if the slab is not cracked, but seems too weak for you to put a wall on it, then place reinforcement under the masonry - this will distribute the load.

Or do you want to support the slab from below with a wall? Is there any reason to doubt the reliability of the overlap? In fact, the data that you indicated (18 cm, two layers of d12 reinforcement, and also a d6 reinforced mesh) should provide excellent strength, even if the reinforcement lies in a 40 x 40 lattice. Unless the concrete is really bad. And if the concrete is normal, then everything should be fine in an area of ​​6 x 6.

If it’s really scary, place a brick column below as a support. Think about how you can fit it into the interior, and that’s it. Although I think this is unnecessary.

Hello! Please tell me whether it is worth securing the reinforcement by welding when laying the mesh or whether knitting is sufficient. I bought a dacha with an under-floored slab between the 2nd and 3rd floors. Instead of a channel, there are railway rails at a distance of 2 meters. If you don’t need to cook, then at what distance should you lay the reinforcement? Thanks in advance.

In fact, welding weakens the metal, so bonding is preferable. The average distance between the threads is 20 cm. It can be reduced, i.e. strengthened, or vice versa, depending on the expected loads on the floor.

Hello master. I would like to receive your practical advice. Are we doing everything right? We want to fill concrete floor between the first and second floors of the future house. Size: 11m x 11m The walls are brick, although the last two rows are foam blocks. In the middle there is a metal beam ceiling. (The formwork has already been assembled, reinforcement 14 and 16. 20x20 cell. 17cm pouring thickness. Brand 300. Will be delivered by car -mixer. Is the grade of concrete 300m sufficient? Is the reinforcement of the correct diameter? Will the floor withstand such spans?

Good afternoon Timur. 11 X 11 is a large area, and most likely you will have partitions on the ground floor, unless of course a gym is planned there. The partitions will support the slab and take on the load. You just need to plan them not from plasterboard, but from brick. Half a brick.

There are no comments or advice on concrete and reinforcement, but it’s not entirely clear about the last two rows of foam blocks. Are they the last ones on the second floor or between the first and second? Well, be that as it may, the upper part of the wall is supporting. Something necessarily rests on it - roof structures, floor beams.

Usually a strong armored belt is made along the top of the wall if the wall is not made of a particularly strong material, such as a foam block, but for you it turns out the opposite.

I won’t insist, since I don’t know all the nuances, but think about it one more time in this regard.

As for the slab, in the sense that it will withstand it or not, come here. To calm the soul. Look at all the points and formulas by which you can calculate the slab yourself. Well, at least approximately.

Hello! I have the following situation: a house with a 9x10m plan. On a larger size (10m) there is another load-bearing wall in the center.
In the project, a monolithic slab with a thickness of 16 cm was calculated, with two layers of reinforcement (the lower one - longitudinal bars d10mm and transverse ones d8mm, their pitch is 20x20cm; the top layer - all bars d8mm, also with a pitch of 20x20cm; there are additional reinforcement elements on the top layer - across the central load-bearing wall there are rods d10mm 3 m long and reinforcement along the perimeter of the staircase opening d10mm - 6 rods on each side). a snake 6 cm high was placed between the upper and lower layers of reinforcement. But in fact, the workers poured a slab with a thickness of not 16, but 19 cm (M300 concrete). What does this mean? Could this have negative consequences? Is it possible to load such a slab with blocks for laying the second floor? If yes, then after what time and, at least approximately, in what quantities?
Thank you.

Good evening Sasha. I understand your feelings. The weight of the slab has increased, but the diameter of the reinforcement has not. Surely now, without re-calculation, it is difficult to say anything specifically. And the calculation is money and not small ones.

But it is not all that bad. Firstly, in the previous comment I gave a link to a resource where good material on independent calculation floor slabs. You can strain yourself to calm your soul.

And secondly, such an element as a safety factor is introduced into the calculation of floors. I don’t remember exactly (you can search on the Internet), but add. the weight of the extra three centimeters (about 1/5 or 0.2) does not cover the coefficient. safety margin. We also take into account that the strength of the slab itself increases with increasing thickness.

Well, purely from experience - differences of 2-3 cm when pouring floor slabs are a common occurrence.

You can load the slab after it has completely dried. How to determine this is in the article. And in what quantities should it be in your project? I simply cannot say this for sure.

In general, apart from additional supports in the form of columns or partitions, there is nothing more you can do in your case. There is an opportunity - do it, but no, I think everything will be fine without them.

Hello. I have the following question: a house 11.5 x 10.5, partitions along the house, but 6 m wide and 10 m long will be without partitions. Will a monolith slab 20 cm thick, two layers of reinforcement 12 reinforcement cells 20x20, 300 m concrete, withstand?

It will withstand (housing loads, i.e. it’s not possible to drive a KamAZ truck loaded there). If you do everything correctly (reinforcement, quality of concrete). And for clarity, wander around the city, find a monolitstroy construction site, walk along it and look at the dimensions of the spans, reinforcement, thickness of the floors, etc. After all better time see (and touch) than hear 100 times.

Master. They poured a small slab on the 2nd floor, 5x2.5m, balcony-terrace. At the bottom along the perimeter of the slab there are 5 support columns, columns 20x30 in diameter. The slab was poured 12cm thick and reinforced with d12 reinforcement, cell 15x15, in one layer. Tell me please make this balcony safe, or better remake it, or strengthen it somehow, the fact is that on this slab, parallel to the lower columns, there will still be supports for the canopy, for the polycarbonate. Sorry, let me clarify for accuracy, the balcony is poured along the building. The house is 2 floors .

Valer, here is a link to the calculations, all the formulas are there http://1popotolku.ru/perekrytie/raschet-plity-perekrytiya.html. But I’ll warn you right away - the calculation is awesome... but complicated. I sat and counted with my stove for a week, my brain almost boiled, and the result was approximate. But as you can see, even with him it turned out okay.

Well, off the top of my head, in my opinion there is nothing to worry about. If the concrete is of high quality, not lower than M200, and there are five reinforced columns in a small area, and the connection to the interfloor ceiling is good. How much can that carbonate canopy weigh?

Of course it can be strengthened. Drill in the legs, put another reinforcement on them. grate, and pour 8 cm of concrete, but just need it. Still, it’s better to strain and count.

Yes, do as I did in the end - load the stove. Architect Lev Aleksandrovich Noskov checked the quality of his bridges in St. Petersburg in exactly this way. He led a crowd of people onto the bridge one person at a time. If it starts to crackle, everyone quickly gets away, and if not, then everything is fine.

The extreme method, of course, is more correct to calculate.

Uv. master. Restoring a house after a fire. Now we don’t want any wooden floors. Only concrete ones.
There is a cubic space: 5.5m*5.5m and height 5m. It is necessary to fill in a 5.5m*3m ceiling, which will divide part of this cube into two levels. At the same time, it should, as it were, crash into existing walls on three sides (two short 3m each and one long 5.5m). Since there will be a second light in the remaining part of the cubic space (there will be no overlap), the main question is: how to strengthen the free edge of the monolithic slab (without any columns below). Maybe make a crown, or is it better to first cast some kind of auxiliary beam 5.5 m long, and only then pour the ceiling? Or don’t “sweat” at all, because in the calculations, it’s a cat. Do you always assume that the designed slab rests only on two opposite walls?

Hello Mikhail. You understand that I won’t sit down to do the calculations now, but I will show you something. My stove also has a free-hanging edge. Where the flight of stairs is. I'm planning an article about the stairs, so I took some photos at the time. The length of this edge is 4.9 meters. The thickness of the slab, as you can see, is 12-13 centimeters. I don’t remember exactly how much, but I increased the amount of reinforcement in this place.

Look for yourself.







As you can see, the screed has already been made and a pack of bricks is lying there and a crane, and this is a clean 200 kg. without the load and me, on the very edge, everything is OK. That's about it. Those. don't sweat it. Add fittings for peace of mind, as much as you see. That's the case when you can't spoil the porridge with butter.

God forbid there is a fire. I sympathize with you from the bottom of my heart.

Hello Nikolay. In the previous comments there is a link to a page with formulas for calculating the floor slab. And as for 18 cm, for example, I have from 12 to 15 cm.

Good evening. Can you please tell me if it is necessary to make an armored belt under the slab? The walls are 300mm aerated concrete! And what are the parameters of the floor slab of the house? 10.6*10.6m in the middle there is a partition and there are load-bearing walls across it. The largest span is 5*6m!

Good afternoon Dmitry. In fact, the monolithic slab itself is already an armored belt. Here the matter is different. Frankly, your question made me think. You write that the wall is aerated concrete 30 cm. Aerated concrete in itself is not a load-bearing material. One floor with a light roof can still withstand an armored belt (garage, small house), but judging by the fact that the floor slab does not end with one floor.

The slab is insulated along the outer end (30 cm of concrete will freeze once or twice), and this is half a brick - 12 cm and 5 cm of insulation. As a result, about 20 cm. 10 cm of aerated concrete remains to support the slab. Will it hold up? Some doubts take over.

If this is an option, then the house is faced with brick. Then, when pouring the slab, it will be enough to only install insulation at the end - 5 cm of penoplex. Then there will be 25 cm left to support the slab, and that’s already something.

Usually the frame is made of a monolith, or a brick like mine (support), and the walls are made of gas blocks.

According to the parameters of the plate. In previous comments I gave a link to a resource with calculation formulas, but the largest span is 5 x 6, the same as mine, even a little smaller, so do as described in the article.

Don’t forget about the additive, Sika ViscoCrete 5-600 N PL, or something similar from another manufacturer. I also wrote about her in the comments.

Hello. I am planning to build a house. 2 floors. Is it possible to use composite reinforcement around the house? Including in the garage floors. The house according to the project will have flat roof. Accordingly, use it in the roof. The most a large room 5x6m. Without additional support. The remaining rooms are smaller. If the use of such reinforcement is possible (even with maximum thickness), then the savings on reinforcement are more than 30%. + less weight, self-delivery, etc. There is nothing reported on the websites about its use in the interfloor space. Only within the walls. I'm interested in your opinion specifically on its use in interfloor slabs.

Here Slava is my opinion, not only on the floors, but in general.

We have just completed a bathhouse, in the foundation of which, at the customer’s insistence, we used composite reinforcement. This was the 3rd case of working with her in my practice, and as in previous cases - swearing through clenched teeth.

I'll explain why. As for working with her. The first thing is to dissolve the bay. Have you tried it? Be very careful. Just loosen your grip or twist a little and it won’t seem like much. Secondly, you need to use protective clothing, etc., as when working with glass wool, otherwise you will get itchy, especially your hands. I’m generally silent about the respiratory organs.

As for saving. Who said it was cheaper? Sellers, perhaps? Composite costs 10 rubles, metal costs about 20 rubles. m. Marketers claim that 8-piece composite has the same performance as 10-piece metal, so it saves money. There is deceit here.

In terms of one indicator - for longitudinal tearing, it may be superior, and I doubt that, since I don’t know who is making it now and on what equipment, but for the rest: for bending, for breaking, for twisting, for abrasion, for impact - it’s close didn't stand.

When you work with it, you can see all sorts of manufacturing flaws: knots, unevenness, fraying.

Google it. This fittings were developed back in the 70s, and were successfully discarded because they did not meet the requirements. And everything would have been fine if marketing had not appeared. And off we go. The material is cheap, and the price is solid. So the brains are completely fooled. The costs are worth it.

Its main and only advantage is that it is easy to transport. That's all.

I apologize for the chaotic answer. But honestly, there is not enough evil. After all, they play on the fact that people are short on money. For the same reason, I fell for it during the construction of my house. Okay, I was smart enough to take a little for testing. I tried it, swore, and let it all go into the blind area. It doesn't matter there.

Thanks for the answer, Sergey. Very well reasoned. Thank you. I thought about it and reconsidered. We will use metal.

Hello.

I'm building a 9x12 house. I've kicked out the first floor, it's time for interfloor coverings. A load-bearing wall divides the house along the long side. It turns out that one half of the house has a span of 11.4x4.6 and the second 11.4x3.5, subtracting the thickness of the walls. I thought about throwing 16th I-beams in increments of a meter, throwing a 5 or 2.5 cm thick block between them and filling the remaining thickness with concrete with a 10th gauge. Why is that. Well, there will be no need to make formwork and less concrete and reinforcement will be used. What do you recommend to do to make it more or less budget-friendly, simpler and more reliable, because you will have to do everything yourself and manually.

Thanks in advance.

Probably the cheapest option is concrete with reinforcement. I-beam is expensive. The formwork is not so scary on such spans, and the material from it will be used for further work.
The hardest part is lifting the concrete to the top. I made a faucet. There is another way to solve this.

What’s good about your option is that instead of concrete, you can pour expanded clay concrete. A smaller fraction of expanded clay and a steeper solution. One of my friends did this about 5 years ago and everything was OK. But more expensive. But the overlap is lighter and it’s easier to work.

Just concrete will work fine too. Slowly you can pour in sections between the I-beams.

Is it possible from without an I-beam?

Of course you can. And more areas overlap. In the previous comments there is a link to a resource with calculation formulas, and the additive brand Sika. It's hard to count. I've been counting for a long time. Finally got the result. And then I found out about the additive and made it thinner taking it into account.

Hello, please tell me what reinforcement can be used to fill the floor slab, I have a guest house 12 by 9, 4 floors, first floor parking, I want to make a completely monolithic structure, I poured a strip foundation with 16 reinforcement, outlets for columns 18, a slab with 14 and 12 reinforcement!

Hello Ivan. From the heart - it’s better to turn to specialists for a project. 12x9, yes 4 floors, yes monolith - a solid structure. We need a calculation.

I wrote about the house a little higher.
What do you think, if you fill a slab with I-beams, and lay the reinforcement as you said in 4 layers on top of each other. What kind of I-beam can be placed (maybe, for example, 12 or even 10 is enough) and at what distance?

If it’s an I-beam, then no less than 16. After all, all the weight will be on the I-beams, and they will gradually bend under the load, metal, after all. Reinforced concrete does not bend. At my neighbor's garage doors I-beam 12. 2.6 meters, there is half a meter of masonry on it, half a brick. Slowly sagging.

Hello. There is a task: a bridge across a stream 4 meters wide and 5 meters long between supports. A gazelle will drive (laden weight 3 tons). SOLUTION: PLATE 20cm thick. reinforcement 12 through 20 in two rows. The strongest CONCRETE from a concrete plant + vibrator. Will it hold up? How long will it last? (precipitation. frost. heat?

You know Lesh, I’ve never done it. Be kind, write back how you do it. Share with people. The bridge is a special matter. Capital supports are needed. Two edges are free. Maybe make a little semicircle along the bottom of the formwork? To the supports. And the top is level.

Good evening. I’m making a cellar: 320cm x 190cm walls, brick floor, monolithic slab floor, tell me the parameters of reinforcement and concrete for the floor slab. on top the ground is 30cm and maybe paving slabs. and what is the ratio in ASG. Thank you

I would do arm. 10 in two layers with a 20 cm grid. Concrete M200, maybe higher for peace of mind, 20 cm thick. M200 is 1x4

I would also advise you to make the lower plane with a small radius and an extension at the highest point.

Hello. Please help me with advice. I want to flood the stove in a 4x4 kitchen. Support - protrusion strip foundation 10cm on each side. There is a 3.8 x 3.8 basement under the kitchen and it is not appropriate to install pillars. I think that you can’t handle a monolithic slab alone. I decided to fill it between the I-beams. Tell me what size I-beam is better to take, with what spacing, what kind of reinforcement, proportions for concrete, without expanded clay. The load on the stove will only be from furniture and three people. Well, tiles. And there is also an option to make 10 from a channel (available, this would make the process cheaper). But it seems 10 cm thin to me. There is an idea to put them crosswise at 80 cm intervals and connect them with bolts(?). Which option is better, in your opinion? And also, is it possible to drill channels symmetrically so that reinforcement 10 can be passed through them, and then placed across it and knitted? Thank you very much.

Good afternoon Dim. In my opinion, an I-beam is an extra hassle and not a small expense. One layer of ten is not enough, you need at least 14, and crosswise - the devil knows, I haven’t done it or heard of it yet.

I-beam is good when expanded clay concrete. And it doesn't drill. Reinforcement between the I-beams across, then along.

If there are so many tens, you can cook them lengthwise, 2 pieces at a time. it will be 20. And the reinforcement will fit well in the middle. There will be a powerful stove. The step can be larger - 1.2 m.

Still, it is better to make formwork, and without a channel. I did one. It's not as scary as it seems. As for the filling: you have about 2.5 cubic meters. You can't do it in one day, but you can do it in two days.

After this slab in the article, I made two more, larger ones. One took two days to fill, the other three. We got joints, but the concrete doesn’t really set overnight if we cover it with film, and the edge is beveled so that the contact area is larger, and that’s it, we can continue in the morning.

Both slabs were fully loaded during construction, just like this one, and everything was OK, not the slightest crack.

Hello Master, please tell me, we are building a box 10 × 20 × 5. The foundation, walls and ceiling are planned to be filled with a monolith, a partition is also planned to divide the box into two halves, that is, its size is 10 × 5 × 0.2, the foundation is 60 × 0.8 × 0.2, the walls are 5 ×60×0.2, respectively, the ceiling overlap is 10×29×0.15. Reinforcement in a circle is A3A500 number 10; apart from the partition, no load-bearing walls are planned. The question is what else needs to be adjusted in my plans.

Hello master, please tell me, it is planned to construct a building 20×10×5, dividing wall 10×5×0.2, respectively, foundation 0.8×60×0.2, monolithic walls 60×5×0.2, ceiling 10×20×00.15, the question is how to calculate reinforcement diameter for all structures. Is the thickness of the walls and ceilings calculated correctly? Please answer.

Hello Alex. In the comments above, I have already given a link a couple of times to a resource with formulas for calculating slabs, beams, and similar monoliths. This is not a simple matter, but it is doable if you have a strong desire.

Hello master, please tell me, I plan to pour a floor slab on a plinth 11*10 exactly in the middle of the plinth in length load-bearing wall plinth made of reinforced concrete M250 distance between the walls of the plinth 4 m wide reinforcement d12 by d10 lower upper d10 by d8 screed thickness 16 cm concrete M250 load on the slab 5 interior partitions in brick + furniture + kitchen + plumbing, etc. Are the calculations correct or have I missed something? Sincerely, your opinion.

Hello master, please tell me, I plan to pour a floor slab onto a 6*5 base, I placed an I-beam size 14 exactly in the middle, reinforced in one row, cell size 20*20, reinforcement 12. Do I need to make a second row of reinforcement? I want to hear your opinion, thanks in advance.

Good evening Vasily. I would do a second row.

Good afternoon. Tell. It is necessary to fill two slabs on the first and second floor. On the first floor there are 110 thick-walled pipes, the distance between them is 1.20. On the second floor there are I-beams with a height of 150 mm with the same pitch of 1.20 and a span of 6 m. In general, there are no 6 by 7 supports. The worst thing I'm afraid of is: the house is made of aerated concrete, where the I-beam lies there is no armored belt, it just lies on the block. Will the block support this weight? The house is completely under the roof, so it will no longer be possible to fill the armored belt. Tell me how to use what kind of reinforcement with what step to knit, brand of concrete, etc. I would like to hear a detailed answer. And how to make formwork

Hello master, I want to fill a floor slab with a distance between the load-bearing walls of 4.5 meters, I plan to reinforce it with d10 reinforcement, 2 layers with a 20*20 cell, I plan to have a thickness of 12-15 cm. I would like to know your opinion on whether it is possible to fill such a slab in parts without using channels and I-beams.

You can’t put the reinforcement like that, two knitted meshes on top of each other. it is necessary to carry it apart by laying at least half a brick between these layers. the plate bends. but concrete does not work in bending. in fact, reinforcement reinforced with concrete will work. but the further the layers of reinforcement are spaced, the stronger the structure will be. If you take two sheets of plywood and put them together, the bending strength will be about a couple of times greater than the strength of one sheet. but if these sheets are spaced apart and rigidly fixed relative to each other, you will not bend it at all... but will only break it in the end...
you have people writing there that there are problems with the floors... perhaps they took your advice.
In short, for large spans, in your opinion, it is not worth reinforcing. at a minimum, the strength of materials is underutilized. for small spans such as a couple of meters - why not. but I would still tear apart the layers of reinforcement.
mention this in the article.

Vasily, the second row is required! read my prev. comment two rows of wire mesh, interlocked with concrete into a spatial structure, are the load-bearing element! The concrete itself does not bear the load (it would simply burst), but it fixes it!!! two rows of reinforcement relative to each other. making her tough. if it is flexible (being single-layer) when loaded from above, the surface of the slab from below will stretch (the slab will bend down) and burst from below. the ceiling will not fail (the rods will rest on the walls) but will move like a hammock.
single-row reinforcement with conventional reinforcement will not be used at all, precisely because of what I said. or reinforce it steel pipes with a diameter of 8-10 centimeters :)

Good afternoon Alexey. I think your comment will be useful, as it is very convincingly justified. Just one question: Have you seen with your own eyes how a slab with such reinforcement bends like a hammock and cracks and breaks?
I did it, gave the load not the central part 15 tons, and then showed it.
Tell me in which comment there are problems with the finished stove, I didn’t find something.

Hello World. After this slab, I poured three more pieces, two of them in parts. One in two days, the other in three. They were long. That is, the filling stopped at night. The result is everything is OK. But I recommend trying to pour it all at once, since I don’t know for sure what kind of concrete you will make, what additive you will use, how you will vibrate it, how you will fit the joints.
This is my opinion, but it’s possible or impossible at your discretion.

Good afternoon Alexander. It's difficult to answer your questions. On some forum I saw the result of the absence of an armored belt. There is a wooden floor beam lying on a gas block, and the wall underneath it is cracked. The man asked what to do. I honestly don't know. It’s not my thing to make theoretical assumptions, but in practice I would never put a beam on a bare gas block, and I haven’t encountered such a phenomenon in my work, so I find it difficult to recommend anything.
Maybe somehow support the I-beams. Maybe the columns could be made of brick, or at least plaster brick, under them close to the wall, so that they fit into the interior of the room. In general, we need to come up with something. The gas block is not load-bearing. It appeared together with the monolith - the monolith is a frame, and the aerated block is the material of walls and partitions, a filler.
Everything else comes later.

I haven’t seen it with my own eyes, I’m just speaking based on the strength of materials and the properties of the materials used. But I can add that if there is only one layer of reinforcement and it is at the bottom of the slab, then it will also work, since it is the lower part that stretches during deflection and in this part the reinforcement prevents stretching. and the upper part contracts, and concrete works well here. since this is a floor, the load is always on top (if there are no retaining walls below in the middle of the slab) and it will also work normally. a second layer of reinforcement in the upper part can also be made, but make it weaker, just to fix the concrete.
however, if there is a retaining wall or column in the middle of the slab and there may already be a load on the floor from below in the middle, then the bending may be in the opposite direction, and it is clear that good upper reinforcement is needed.
that is, the position of the reinforcing elements depends on the directions of loads on the product. reinforcement should be where there are tensile loads on the concrete. where compressive reinforcement loads can be minimal.
Regarding the arm layer - it is generally required, even for brick house. not like lightweight concrete, such as aerated concrete blocks. as you rightly said, the load-bearing capacity of aerated concrete is low, the fragility is high, and local load will destroy aerated concrete. The armored belt saves, distributing the local load over the entire wall.

Well stated.

Hello! I'm going to pour a slab on the roof of the terrace. but at the same time make an exit to the balcony on the roof. Can you tell me how to do it correctly? what to install and in what order (para-hydro insulation, insulation, etc.) thank you!

Good afternoon Alexander. Damn, I've never made a balcony before. There was a crew working next door, but there was no time to look. Sorry, I can't do anything.

Tell me, is an additional base needed in the middle when pouring slab reinforcements at a distance of 3/12, like a ceiling, if there are 2 walls?

Hello, here I am Two-storey house 10 by 11 monolithic ceiling: thickness 10 cm, reinforcement 10 at the bottom, 12 at the top, like a mesh, goes with intervals of 20 by 20 cm. Sank in one place up to 12 mm and in a circle 9-10 mm. They wanted to make a screed and they said that it was dangerous; and right now we are thinking about sheathing with plywood? Is it right? And what do you think about this? Interested in your opinion _? Thank you in advance

I would think about how to make a support. A column at the bottom or something like that.

Is there a risk of collapse yes_? ((And what weight per 1 square meter can a reinforced mesh withstand; Do you need photos???

Make a column where the monolith sank by 12 mm? It sank apparently from the beams on which the upper monolithic ceiling was supported, or under the weight of the brick when they laid the brick on the second floor - one of these reasons apparently ((

There is probably a risk Rashid. You don’t need a photo, you need to look at it locally, but you still can’t really understand it from a photo. How much weight it can withstand requires a complex calculation. Think about where to put a post or a partition.

Hello! We need your advice, like many here) We installed an extension 4.2 m * 8.2 m, the foundation is FBS, the walls are arbolite, and under all this there is a base 2.6 m high. Now we need to pour a slab that will serve as the floor under bathroom and toilet. Slab size 2m*4.2m. Our question is the following: how to properly fill the ceiling so that while bathing in the bathroom you don’t suddenly collapse into the basement?))))) I’m very far from this, I tried to calculate using formulas and realized that I didn’t understand anything))) So I really hope to your answer. Thank you in advance!

Hello Marina. I don't think you should have any problems with the stove. Do as I do and everything will be OK. But what it will rely on - this should be decided on the spot. If I understand correctly, it will be adjacent to three walls. Is there anything to support the stove on? On the fourth side you can install a retaining partition in the basement. Or a column, and reinforced reinforcement along the edge of the slab, i.e. add reinforcement along the edge to make it look like an armored belt.

That's the point, Master, that part of the slab will rest on the foundation, i.e. 2 m of slab on one side and 2 m on the other. And the remaining two sides, 4 m long, are suspended. The bathroom is in the middle of the extension, so it happened that way. We thought about I-beams, if we lay them down and support the “hanging” sides on them, is this a suitable option? And support the slab in the middle in the basement brick wall, which in turn will divide the basement into two rooms. So, probably, there will be less chance of taking off into flight while lying in the bath?)))

So-so. Now it’s more or less clear. So, how do you get a swing bridge, 4 m long and 2 m wide. The only question is how to make supports in the basement.

The partition in the middle is somehow not very good. It is better to have a partition along one edge, and a couple of brick columns under the other edge. Just so that the supports themselves do not sag, i.e. there is also a type of foundation under them.

I once did something similar, only 3 m long. Without supports. I made the bottom plane a hemisphere. I built bricks along the walls to support the lower plane. True, I had to tinker with the formwork, but it turned out great.

THANK YOU FOR YOUR HELP!)))) If you have any more questions, we will only contact you, if you allow!)))

Allow me Marina. Actually, I'm always happy to help.

Master, hello. I am building a house 12*13m. External walls are aerated concrete blocks, internal partitions are 1 row of red brick. Reinforced columns 15*20cm are poured along all wall joints (about 19 columns, reinforced with 4 pieces of 14-rebar). Then a reinforced seismic belt of 25*25 cm is poured (reinforcement of the seismic belt with 12-reinforcement in two rows: bottom row 3 reinforcement, top row 2 reinforcement). Then a monolithic floor with a thickness of 13-15 cm was poured. Reinforcement of the floor is 2-row: the bottom row is with 12*6mm reinforcement in increments of about 30 cm, and the top row is also with 12*6mm reinforcement in increments of 30cm). Now I want to make an attic under a regular triangular roof. I want to make the outer walls of the attic (two gables + two walls under the slopes with an inward displacement of about 2 meters from the outer walls of the first floor) from aerated concrete blocks 30cm (thick) * 25cm (height) * 60cm (long). The gables will be erected on the external walls of the 1st floor, and there will be no load on the monolithic floor. But if I build two walls between the gables made of aerated concrete and there is no wall underneath them, but only transverse partitions with an armored belt, will the monolithic ceiling lift such a weight? These two walls between the gables will be 1.75m high (7 gas blocks) and 12m long. And the maximum span: 4.5m*5.5m (hall) and 6m*3.5m (hall). If the gas blocks go over the hall and over the hall right in the middle, will the monolithic ceiling hold up? Plus, there will also be a load of furniture that will eventually be placed in the attic. What do you say?

Hello Ibrahim. I’ll say, if in doubt, load the slab with the planned weight, then everything will be clear. But even if everything is OK, I would make a small foundation under the attic walls, like an armored belt, approximately 30 x 20, 4 strands of 12 reinforcement, to distribute the weight of the wall. .

Master, thank you very much for your response! The builders tell me that the monolithic ceiling will raise the weight of the gas block, since above the hall the wall (7 gas blocks 1.75 m high) will go not along, but across, that is, the span will be 3.5 m (not 6 m). And above the hall where the attic wall will pass (7 gas blocks 1.75 m high) the span will be 4.5 m. That is, they assure that the maximum span of 4.5 m will withstand such a load. Will there be any problems if I trust them, or do I definitely need to fill in an additional armored belt, as you wrote above? How critical is this?

No, not critical. Reinsurance. As they say, in such a matter it is better to be safe than sorry.
And the first part of my answer is load the slab. Pick up these blocks there and just put them there for now. Raise more for mortar, plaster, trim, furniture, etc. If the slab can withstand the load, then you can build. If it cracks, it means problems - you will plan retaining partitions.

Master, thank you for helpful advice!!!

Hello Master! Tell an amateur: is it permissible to pour a slab in a room with an area of ​​2x2 m of a wooden frame on a part of the crown 150x150 mm, protruding from the walls by 5 cm along the entire perimeter? I think both the area and strength of the support are too small (?)

Pour the slab onto a wooden support around the perimeter? Did I understand correctly? Tell us in more detail what and why, maybe I can recommend something better.

Hello Master! The task is the following. There is a log house of a bathhouse 4x6 m on a columnar foundation (monolithic piles d20 cm, interval 1.5 m, height 0.5 m, depth approx. 1.5 m, between them the filler is expanded clay concrete). The lower crown is a beam 150x150 mm, on it there is a beam 150x100 mm (stands vertically). The remaining 5 cm are supports for arranging the floors. One of the 2x2 m rooms is planned for a bathroom, the floor of which would now like to be made concrete - support the slab (10-12 cm) on a 5 cm protrusion along the perimeter and tighten the slab reinforcement (before it is poured) with the crown adjacent to it . However, the design seems unreliable, especially given the passage of time. Apparently, the only option left is to pour 4 more piles inside the room in the corners, make a screed on top of them (20x20 cm) and pour a slab on top of it. Maybe you know of any other solutions? To be honest, I’m afraid that, unfortunately, I’ll have to go back to the original version - with a wooden floor. Thank you in advance!

Good evening Vyacheslav. There is no need for pillars or slabs for the toilet. This is such a gimmick. I can’t imagine how to make the formwork and remove it later. Cover this area with expanded clay. That is, make a 2X2 half-brick masonry and fill it with expanded clay inside. To save money, you can use up to half, sand, and then expanded clay. Lay the roofing material to the lower beam for insulation and make a regular screed on expanded clay. There is no need to reinforce anything, you just need to pour a tape under the masonry about 15-20 centimeters high.

Hello, master! Everything ingenious is simple. Thanks for the advice.

Hello Master!
Question about the ceiling above the terrace, to the already built one brick house 10x10 this summer built an extension in the form of columns made of two bricks with reinforcement and strapping on three sides with a 40x30 reinforced belt with six bars of 12 reinforcement. There are only eight columns. Now I want to fill the ceiling with expanded clay concrete, laying half a brick of the reinforced belt along the outside of the type of permanent formwork and using 16 channels with reinforcement of the lower and top shelves channel 12 with fittings. Supporting the channel on one side on the armored belt of the extension, on the other side in niches outside houses that go through about a little more than a meter. I can’t decide what to fill, just concrete or expanded clay? Thank you.

Good evening Denis. I apologize for the delay in response - I spent a week on the islands.

Actually, based on the way you describe the design, you can make expanded clay concrete. The question is what do you plan to finish the ceiling. In expanded clay concrete it is almost impossible to hold the dowels, so if you have a frame, then attach it to the channels. If it is plaster, then the channel must be covered with expanded clay concrete, that is, when making the formwork, a 50-gauge block is sewn onto the bottom of the channel and the formwork is attached to it, then the block is removed and its place is filled with mortar. The total thickness of the slab in this case will be approximately 20 cm.

Hello Master. Please tell me how to make a floor slab for a cellar in a garage? The size between the walls is 2.35 by 2.45 m. The walls are concrete with 12 mm reinforcement, 30 cm cell. What reinforcement to use and what mesh to knit. Is the grid two rows or is one enough? What thickness should the floor be? A passenger car weighing 1350 kg will stand on the ceiling with a partial drive. And is it possible to somehow insulate it? Thanks in advance.

Hello namesake. My cellar is about the same size. A little more. Cover with hatch. Thickness 10-12 cm. Reinforcement 10, tied into a double lattice 20x20.

By insulation it is possible different variants, if you think about it. For example, I have 50 mm foam on the lid, and the garage floor is poured on top. Also with fittings. Also 10 in one layer 20x20.

It can withstand the Niva without any problems.

Thank you very much, master! How thick should I fill the floor (with reinforcement) so as not to push through the foam? Would you like to win on thickness? Is 5 centimeters enough?

Not Seryoga foam, but extruded polystyrene foam. Penoplex.
I won’t say 5 cm, I have half a centimeter of 15-20 over the entire area. I poured the floor on a sand cushion, just above the cellar with penoplex.

If you make the floor thinner, then it’s probably better to strengthen the reinforcement above the penoplex. Let's also add a 20x20 lattice. But even then 5 cm is not enough, since the thickness of the lattice, if from 10, will be 4 cm. It is necessary to cover it with concrete. Well, at least 10 cm is needed.

Can the walls of the cellar be made lower? There are options if you think about it.

Thank you very much, master. The fact is that the walls are already ready. And there are some nuances: the walls are lower, the ceiling height is quite small, and digging deeper can cause flooding in the spring (like the neighbors). But I think 10 centimeters and maybe more. Thank you. You are doing a good job.

Hello, Master! Please tell me after how many days you can remove the retaining posts from under the floor slab cesspool measuring 2*2*0.15 meters, taking into account the fact that it will need to be covered with a 30 cm layer of earth on top. Suggested by you in the comments method-using roofing felt, I think, will not be entirely correct, because... It rains endlessly (the hole has been standing for the third day and it has been raining for the third day). The air temperature is about 8-10 degrees. Thank you in advance for your response!

Good afternoon Victor. The fact that it’s raining and not hot is good for concrete. I hope they covered it with film so it wouldn’t wash out? In such conditions, within 10 days the formwork can be removed, but loaded only a month after pouring.

I think it’s unnecessary to clarify about the quality of concrete.

Thank you, Master! If only there were more people like you, life would be brighter and more beautiful!

Please tell me.
I want to pour a floor slab in utility room measuring 2 by 3 meters.
I plan to lay the slab on vertical pillars-supports along three-meter walls - four columns on one side and four columns on the other side. The size of the posts is approximately 15 by 25 cm. I will not make supports for the slab on two-meter walls.
The maximum load on the floor slab is no more than 400 kg, not counting the weight of the slab itself and the screed with tiles.
In the middle of the long side (like the average pocket in billiards) a hatch into the basement measuring 70 by 70 cm is planned.
Questions like this:
1. What should be the minimum thickness of the floor slab? Is 10 - 12 cm enough or do you need thicker?
2. Some advise having only one bottom layer of reinforcement mesh, but some advise two layers - top and bottom. How many layers of reinforcement do you need to make? Is it enough to use reinforcement with a diameter of 8 mm?
3. What cell sizes do you need in the reinforcement mesh? 20 by 20 cm wouldn't be rare?
Thanks for the answer!

Good afternoon Alexander.

1. A slab thickness of 10-12 cm is possible if the concrete is made with a superplasticizer. For example, Sika ViscoCrete 5-600 N PL, if without it, then the thickness is 20 cm.

2. Two layers. Reinforcement 10 mm. If without an additive, then a bench is used to form the layers (a reinforcement element holding the layers at a distance of 12 cm from each other).

If with an additive, then two layers on top of each other with an offset, as shown in the article.

3. Cell 20 x 20

This is by calculation. I have exactly the same ceiling with a hatch, but along the walls, and not along the supporting pillars. I made it with an additive. In addition to the calculation, in your case I advise you to strengthen the reinforcement along the edges by several threads.

Thanks for the answer.
I have restrictions on the thickness of the slab, it can be no thicker than 15 cm, so that its thickness does not go above the threshold in the doors and below the technological holes in the basement wall. Buying Sika ViscoCrete 5-600 N PL for one such slab is expensive for me (85 euros for 25 kg minimum weight).
What can be done to reduce the thickness of the slab?
1) Is it possible to place reinforcement more often, for example, every 15 or 10 cm?
2) Either install more support posts, or instead of these posts, pour a solid support wall under the support of the floor slab?
If instead of supporting columns I fill in a solid supporting wall on the left and right, then I will get a real floor slab in the gap between the supporting walls of about 1.7 meters (and at the ends of the three-meter side I will put one column on each side in the middle for support).

In Kazan, Sika is sold on tap. Well, okay, exactly the same result can be obtained by vibration. The area is small - knead it thicker and quickly fill the vibrator. I won’t dwell on vibrator options. From the improvised ones.

Hello!
At the beginning you described how you made a large monolithic slab 5x6.5 m, 15 cm thick. You laid a reinforcing mesh with a diameter of 10 mm with cells 40 by 40 cm. Then you laid the same one on it only with an offset of 20 cm , that is, half the cell. This eliminated the need for making chairs. Then what, you just got the bottom layer of the reinforcing mesh, without the top? Then what is the point in two grids, you could immediately make one layer but 20 by 20 cm? Then what, can you make a slab with only one bottom layer without a top one? Or did I misunderstand something? Thank you for your reply.

Try it in one layer, then we’ll find out. My reinforcement turned out not at the top and bottom, but in the middle. The thickness of the mesh in 4 rows is approximately 5 cm, with 4-5 cm of concrete on top and bottom. That’s it. The result is good. We'll wait with interest for yours.

Thank you.
No, I'm not planning the way you thought. I think there is 2.5-3 cm of concrete underneath.
Then 10 mm reinforcement parallel to the short wall.
Then 10 mm reinforcement in parallel long wall(although maybe you need to do the opposite, immediately along the long one, and then along the short one? Please advise which is correct?)
Then concrete 10 cm.
Then 8 mm reinforcement along the short wall.
Then 8 mm reinforcement along the long wall.
Then concrete 2.5-3 cm.
Total thickness 15 cm.
Reinforcing mesh cells 20x20 cm.
I think so.
And I already asked the question - what type of reinforcement should be placed along the long or short side?

Starting along a long or short one makes no difference, it will still be a monolith. But the eight reinforcement is in doubt. I have not done and have never seen figure eight used in a monolithic slab. To dispel doubts, you need to make a calculation. I have already given a link a couple of times in previous comments to a site with formulas.

And so the design is quite workable, if, of course, you figured out how to raise the upper grille above the lower one by 5 cm, and make the entire structure rigid. Considering the thickness of the reinforcement, the bench will have to be made three centimeters out of ten, which will be difficult, if not impossible.

Good day to you, Sergey! I am building a house on a slope, with my own efforts, alone. Took the most uneven place ground floor 6x9. I poured the floor slab using a concrete mixer. Between the number 9 there is a wall made of expanded clay concrete blocks 40 cm thick (all walls are 40 cm thick, expanded clay concrete blocks). Oriented the reinforcement to dia. 12 mm for a size of 4.5 meters with a frequency of 15 cm, and in length (6 METERS) WITH A FREQUENCY of 30 CM. The thickness of the fill is 18 cm. I am not a builder myself, but I hear different advice... some say that this ceiling will withstand a loaded KAMAZ, and some say that it is weak.
Thank you! Sergey Ufa

Good evening namesake. For now, it’s good to evaluate the ceiling, since there is one point, namely, in fact, two layers of reinforcement are being made, that is, two gratings. But since there is no calculation, and the slab is already filled, then do as I do. You are just starting construction, so you will have the opportunity to test the slab by loading building materials on it. I once loaded 3 thousand red bricks, the slab held up and the issue disappeared.

From the bottom of my heart, I wish everything was fine. I will always share everything I know - just ask.

Good afternoon, master. And if the metal reinforcement is replaced with COMPOSITE GLASS PLASTIC REINFORCEMENT, will anything come of it??? And how can she show herself? (it is both lighter and, they say, cheaper...) What do you think??? Or is it not even worth considering this option??? Thank you!!!

I have already written about this. Composite material will not replace metal. All its unprecedented advantages are pure marketing. It was invented back in 1972, and since then it has never been put into mass use.

I worked with her several times. The undoubted advantage is that it is easier to bring, but working with it is a complete hassle and misunderstanding, especially with large volumes. Little things will do.

Thank you, MASTER!!! And also, tell me... my house is 10X10 old, it’s already 50 years old... made of shell stone - the wall thickness is 50 cm, on clay. If I make an extension to it another 8x12 meters (I want to make a kitchen, bathroom, etc. in it, but all the amenities in the yard in summer kitchen) make this extension with a separate foundation. And remove the roof of the old house and fill it with armored belt. And then pour everything together on top with one continuous reinforced reinforced plate. I want to make a couple more rooms on top using lightweight foam blocks... Will I be able to do anything? Or should it be demolished? an old house...? Thank you very much! (even if you don’t answer….)

Eh Seryoga, I would be glad to give you some advice, but this can only be determined by location. Soil, foundation, condition, etc., etc. Touch, pick, knock, think. So, stop recommending such things from afar.

Happy New Year!!!

Thank you, Sergey! Happy New Year and Merry Christmas to you too!!! In general, what I asked can be combined with one slab with an armored belt, and reinforced with internal and external plaster? Our soil is alumina... thank you!

In theory it is possible. Alumina and shell rock are reliable things. If also plaster with chalk.

But in our country shell rock is not plastered on the outside. We have it like finishing material coming.

Thank you, namesake!!! Merry Christmas and Happy Epiphany!!! (I’ll write when I do it... but it will be in the fall) Once again, Thank you!!!

God help you. From the heart.

Hello. Tell me please. This is the situation between the first and second channels laid at a distance of 1.15. height 20 centimeters length about 9 meters. on one of these spans there will be a brick partition to overlap the ceiling beam. what is the diameter of the fittings? how many rows? what point? thank you in advance.

Eldar. To answer such “simple” questions, you need to do a full calculation of the slab. More accurate data will be needed. In the comments above there is a link to a resource with all the formulas for this. I’ll warn you right away that there are quite a few of them and this is quite a lot of work. And no one will do it for free. There are, as usual, two options: either pay for the project, or try to calculate it yourself, and if it doesn’t work out, then do it at your own risk and responsibility.

Good afternoon I need your advice.
During construction, an opening was cut out between the floors in a monolithic slab for a wooden staircase. The result was a two-story apartment. Now it is necessary to restore this slab and remove the staircase. Size 300*95. Repairs have been completed everywhere. How can this be done as carefully and reliably as possible? They suggested option 1. Make a frame from a metal corner, there are two platforms. One for pouring the floor on the second floor, and the other for fastening the ceiling of the 1st floor. The fill is supposed to be 90 mm screeds using a metal profile with the insertion of reinforcement. But no reinforcement is expected drill into a monolithic slab anywhere, but only lay it to strengthen the concrete. Under the concrete layer there will be a soundproofing layer and drywall. The thickness of the slab is only 200.
Or option 2.
The metal profile will be laid on the edges of the slab, the reinforcement will be inside, then 90 mm will be poured in, followed by sound insulation and plasterboard. The rods are not connected anywhere to the old monolith.
Tell me, please, is it possible to do this?
On the second floor there are tiles on the floor and kitchen furniture
Sincerely, Marina

Good evening Marina. I can’t tell you exactly what is right and what is wrong, since such an issue can only be resolved on site, and not remotely. It is not clear which metal profile - there are a lot of them, and it is not clear what finishing has already been done and how it will be connected to it.

I’ll just tell you how to connect the finished monolith with what is to be added to the existing one. Namely reinforcement. The levels of pouring and installing formwork are again only on site. In the finished monolith, a hole is drilled for the reinforcement, at least 25 cm deep, which is filled with a special two-component glue, and then a piece of reinforcement with a length of 50 cm is driven into this hole. The holes are made every 20 cm.

Then two transverse threads are tied to the protruding reinforcement, and then the entire reinforcement is formed on this support. The thickness of the slab is at least 15 cm. Everything else is for insulation, screed and finishing coat.

Please tell me. What layer of concrete to pour for a span of 5m. and between 100 I-beams there is a gap of 1.5 m. I want to leave the boards as formwork on the beams.

Good afternoon Yuri. Complex issue. In fact, I would generally be wary of placing an I-beam of one hundred square meters on such a span of flooring. I think it’s a bit weak. In general, before you start, consult with other people 10 times.

A layer of 10 cm is a bit thin. If you pour it thicker, it will be thin above the beams; the beams themselves are rather weak. How will it support the weight of concrete? The reinforcement binds the concrete, and the beams, on the contrary, divide it into strips.

I don't know Yura. Don't torture. Here only calculation can give an accurate answer.

Master, good afternoon. Please help me make a cellar ceiling. I can’t find how to properly lay out the fittings for filling a lid measuring 1.7x1.8. In one of the corners there will be a hole into a cellar measuring 700x800. There is a lot of information on floor slabs for large spans, but there is nothing for spans up to 2 meters. What is the diameter of the reinforcement, cell. Thanks in advance for the advice.

Almost the same lid is made on my cellar. I didn’t think it would be interesting, so I didn’t make material on it.

The data is as follows: a dozen reinforcement, a cell of 20x20 cm. On the first lattice, a second one is made, the same but with an offset of 10 cm. The thickness of the concrete is 15 cm. Along the edge of the lattice there is additional reinforcement along the perimeter at the top and bottom.

In fact, the reinforcement depends on the expected loads. If a small room is heavier than your loved one, and even some small thing like a bag of potatoes and a wife is not loaded on this lid, then one grate will be enough. A smaller cell, say 10-15 cm, and that’s it.

Well, if it’s a garage, then as I wrote at the beginning. The car still gets there - the weight.

To prevent frost from appearing on the cellar lid, in addition to insulation from above, make the hood flush with the ceiling of the cellar, i.e. with the bottom of the slab. Ideally, make the bottom of the slab slightly spherical (work with the formwork) and make the hood at the highest point.

Eh, I’ll have to get busy and prepare the material. I made a really good cellar.

Thank you very much for the information. The cellar remains under the wooden floor, so there will be no load at all. I filled it in, everything is ok. The formwork was left for 28 days. Increased the diameter of the reinforcement to 12 with a 20x20 cell. The thickness of the slab is 120. It should work. Thank you.

I think everything will be ok

Master. Good afternoon. I report on the filling of the cellar lid. Yesterday I removed the formwork, having previously made control points with a laser level, the middle of the slab settled by 2 mm. I think this is excellent. How do you think?

2 mm. for a concrete slab this is practically nothing. Keep it under the film longer - the guarantee against cracks will be stronger.

Master,
so you never made a story about your cellar.
I have the same problem.
Span length 3.5m width 1.4.
There will be a hatch cover to the cellar.
There will be a bath and a bathroom on the stove.
where the hatch will be is a rather weak place.

How to play around with everything and what kind of fittings to use?

Yes namesake, sorry. It’s spring—the work is over, there’s no time for stories. I can’t even respond to comments in a timely manner. I'm surprised how there is enough health for everything. Apparently I ate a lot of pollen last year.

As for “beating” - strengthening the perimeter of the hatch is not a problem. And the entire overlap can be strengthened for peace of mind. For example, the cell is not 20 cm, but 15 cm. The area is small, which means the consumption is not large.

I think I answered in the comments (I don’t remember), my cellar ceiling is 10-12 cm, there are dozens of reinforcements, I added several threads of reinforcement around the perimeter of the hatch.

Insulation is 50-gauge penoplex, along the perimeter of the penoplex, where the hatch is, a 50-gauge corner, a welded square, then the screed is relatively thick - 10 cm. In the screed above the lid there is also a dozen reinforcement, a single layer of grating.

Wooden hatch - larch and frame and cover. On the bottom of the lid there is 50-gauge foam. I just can't get around to decorating the bottom of the lid.

On the Niva I drive on the roof. Sometimes I accidentally hit the hatch. Doesn't press through.

Hello Master. I want to make a monolithic ceiling attic house. The largest area in the house is 3.8 m. at 7m. In order to save money (without compromising strength), can I make the reinforcement of the monolith single-layer, adding a 1.5 m space frame through which the reinforcing mesh passes and is poured with concrete at the same time (like a beam)
Please advise. Thank you in advance.

The design with the frame is interesting, but I cannot advise anything specifically in this case, since I have never made such a spatial frame, and I don’t know anyone who has done it, so I can ask.

Good afternoon. I tried to find information on the Internet about the minimum thickness of the floor slab, but I couldn’t find it yet.
Situation - there is a large canopy made of corrugated sheets, about 8 m by 7 m. In order to rationally use the space above it, I plan to plant grapes there over the entire area (possibly on pipes parallel to the canopy at a height of 2 meters above the canopy. I haven’t been smart enough yet how to solve the problem walking on a canopy made of corrugated sheets and attaching pipes to set up a vineyard.
I see a solution only in replacing the corrugated flooring with a concrete floor of minimum thickness (naturally with concrete columns and crossbars). According to the concept, I am planning a slab of 8-10 mm reinforcement in two layers. The thickness of the slab is about 10-12 cm, the first mesh is 2 cm from the bottom level of the slab, the second is 4 cm from the top level of the slab, 1 bottom mesh reinforcement is 10mm square 200x200,
the second 8mm 200x200 cm with a staggered offset in relation to the bottom. Because We have problems with mixers in the mountains, we’ll have to pour it in manually, I intend to slightly increase the strength with plasticizers.
Can you give me some advice? Point out the errors in the above.
PS Since nothing other than a vineyard over the canopy is planned, the slab needs a minimum thickness. Although, if there is an ingenious solution to solve the problem with a vineyard over a canopy made of corrugated sheets, I will be very glad to hear. I can send you photos of the canopy.

The idea is certainly interesting, but it’s labor-intensive. You can reinforce it as you write, and make the slab with the Sika additive 10-12 cm thick. But how many columns will need to be installed is the question. What are the columns made of? Also pour? Or is it possible from stone? Or made of brick?

If there are about 2 meters around the perimeter of the column and in the middle there are three more pieces, where there are 8 meters. I can’t say for sure, but in my opinion it will hold up. You can add reinforcement around the perimeter, like a belt.

But it’s still up to you to decide. As for other options, you need to know local conditions, prices, and available materials. Possibly welded metal structure It would be better, perhaps wooden, perhaps both Wooden roofs They stand under roofing felt without any problems, and if instead of roofing felt there is TechnoNIKOL, it will last for a long time. In short - think head. Advice is advice, of course they are needed, but you still have to choose the final option yourself.

Hello Master.
I'm trying to build a house on my own. I reached the stairs, for which there was space left, i.e. Floor slabs are not installed. Now we need to fill this hole. The hole is a “G” axle box, the long side is 4.5 m, the short side is 2.5 m, the width is 1.2. A corner 63 with a thickness of 4 is attached to the floor slabs that are already lying (on top and bottom), after 1.2 from the healing slab on the load-bearing walls of the house, a profile pipe 80x160 with a thickness of 4 is placed. This profile pipe and the corners on the slab are connected by the same corner. It turns out that the letter G is divided into sections measuring 1.2x1.5. These sections contain reinforcement with a diameter of 16, in the form of a grid measuring 20x20, which turned out to be in the middle of the slab that we plan to fill.
Please tell me:
1 is enough reinforcement in one layer?
2 Is it possible to fill it not at once, but in squares, for example?
3 is it possible to make a solution with expanded clay or is it still not possible, people will only walk around this place in the future
Thank you in advance.

hello, I have a question, I want to pour a slab on a sewer well, its size is 250*100, one layer of reinforcement can be laid, or is it better to lay 2 layers of reinforcement

Good morning Vlad. Depends on what's on top. In terms of load. I'm driving over a well in my car, so I did two layers. the size of the well is a ring of 1.5 m. If there is dirt on the lid, and there is a rare pedestrian, then one grate of about 20X20 out of ten is enough, and a reinforcement of a couple of threads along the hatch.

Good morning Marina. In my opinion, all three of your points can be safely accomplished. And there is enough reinforcement, and you can pour it in parts, and ceramic concrete is possible, only a stronger solution, i.e. more cement.

And before pouring, treat the edges of the slabs with primer, such as sprayed cement laitance, or at least remove any dust well. and after pouring, cover with film for a week to prevent it from cracking.

Well, for greater peace of mind, you can drill reinforcement pins, 20 centimeters each, into the ends of the slab. It’s not difficult. Although, according to your description, the reinforcement is powerful.

Thank you very much. The opinion of a specialist is very important.

Master, good evening. Tell me about the ceiling in the basement 1.6×5.5 with a hatch. It is possible to support 2 walls of 25 cm each using 14 reinforcement in 2 layers with intersection.

Hello, can you please tell me that a monolithic slab on the second floor will be poured in the center of a load-bearing wall (9 by 8 by 0.2 reinforcement 10 in two rows of cells 20 by 20 concrete 250) in the living room there will be a bay window with a radius of 150 cm, is it necessary to make columns for it? Thank you.

And so and so is possible. If there are no columns, then strengthen the reinforcement.

Maybe. I have a cellar this wide, albeit shorter - 3 m, but there are dozens of fittings. I can easily drive over the road surface on the Niva. Only the hatch is reinforced with reinforcement.

Good day. I'll ask a question too.

I want to make a monolithic ceiling of the first floor measuring 5000 x 10,000. The ceiling will lie on a cushion of sand and gravel, resting with its edges on a monolithic foundation strip 400 wide. It will rest on the slab itself internal partition made of aerated concrete, this partition will stand across the house, dividing it into rooms 5000 x 6600 and 5000 x 3300. Actually, the question is. If I add two additional cross strips to the foundation, thus dividing it into 3 “squares” of 5000 x 3300, would it be acceptable to make a 150-thick floor with one reinforcement mesh at the bottom of the slab? Or is it better to fill a solid ceiling with a thickness of, say, 200, with two meshes, without any tape, and not invent garbage? So far, the option with additional tapes looks much cheaper - these tapes require much less reinforcement than a full-fledged second mesh.

Oh yes. My area is quite wet, with high water about 2 meters from the surface. I live in the south of Russia, the coldest winter is 20, but this temperature does not last long. The building will be heated.

Good evening Mikhail. Divide into squares and make one grid. It's on a cushion of sand, not suspended. For example: this is how I made the garage floor 4.5 x 7 m. Without partitions. Relies on the tape.
The owner of the Padzherik has more than 2 tons. Nothing, already 7 years and not a single crack.

I can’t say anything about verkhodka. Not a simple question.

Without such an element as reinforced floor slabs, in modern construction it is almost impossible to get by, even if we are talking about a small private house. Reinforcing the floor slab is quite feasible on your own, even if you are new to construction.

Floor reinforcement – ​​what do you need to know?

Reinforcement is a technique that is found everywhere. This is how stair steps, arched lintels and, of course, monolithic floor slabs are made. The technique consists of combining two materials with different structures - concrete and reinforcement. While concrete is strong but quite brittle, the metal from which the reinforcement is made has sufficient elasticity to withstand vibrations and vibrations. Reinforcement, in fact, is the skeleton of concrete - without it, it would very quickly crumble into pieces.

The thickness of the reinforcement varies depending on the application; in residential construction, a section from 8 to 14 mm is usually used, while the thickness of the slab itself is expected to be up to 150 mm.

If you are buying slabs, keep in mind that according to the cross-sectional structure of the product, there are solid, ribbed and hollow. The latter are the most popular, since among their advantages is their relatively low weight, they have high rates of heat and sound insulation and tolerate deformation quite well. However, all purchased products have one significant drawback - the presence of joints that do not always coincide, forming steps. When creating a monolithic slab, you get a smooth and uniform surface.

Possibilities of reinforcement - savings and insulation

The use of reinforced structures allows not only to achieve significant insulation of the entire building, but also to significantly speed up the process of constructing the entire building. The low weight of reinforced slabs and other structures significantly reduces the load on the foundation, while the structure itself is very durable and can easily withstand high stress and prolonged exposure to fire. According to statistics, wooden floors can perform their functions under fire for about 25 minutes, while monolithic slabs will withstand more than an hour.

The use of this structural component allows the construction of buildings of any size and complexity. Using floor slabs, you can correct incorrect room geometry and create floors of non-standard dimensions. The possibilities for planning a house increase significantly, since not only the walls themselves, but also internal arches and columns can serve as support for this type of ceiling.

The site’s site masters have prepared a special calculator for you. You can easily calculate a monolithic floor.

DIY monolithic floor slab - reinforcement diagram

To find out the thickness of the future floor, builders use a simple formula - the span length is divided by 30, the resulting figure will be optimal thickness. The traditional slab reinforcement system consists of placing working rods at the bottom and top of the slab, which redistribute the load of the reinforcement and wire rod stops. If the slab thickness is no more than 80 mm, just one layer of wire mesh is sufficient for reinforcement. It is important to raise the mesh so that it appears to be inside the concrete, at least 2-3 cm.

The mesh can be either twisted wire or welded - the latter method is advisable to use when the diameter of the reinforcement is at least 6 mm. If the thickness of the slab has reached or exceeded the limit of 150 mm, reinforcement must be done in 2 layers, placing them on top of each other and tying them together with wire. The cell size must be at least 150*150 mm, but not exceed 200*200. For the most durable result, it is advisable to use reinforcement of the same cross-section; if you want to strengthen the slabs even more, use rods 40-150 cm long in connection with the main structure.

The load on the structure is distributed as follows: the main loads fall on the lower reinforcement, while the upper one experiences a compressive load, as does the concrete. The reinforcement process should be carried out over the entire area of ​​the monolithic slab, necessarily using formwork, which is traditionally made of wood or plywood. The formwork posts must be secured as firmly as possible, because just one square meter of flooring can weigh up to 300 kg! For reliability, it is much better to use telescopic stands that can support 2 tons of weight.

Do it yourself: reinforcement of a monolithic floor slab from A to Z

For reinforcement, it is recommended to use hot-rolled steel reinforcement of class A3 - its diameter, depending on the expected loads, is from 8 to 14 mm. The first mesh is laid in the lower part of the slab, respectively, the second - in the upper part. The formwork must be positioned so that the mesh is located inside the slab, and the protective outer layer of concrete reaches about 2 cm. The reinforcement is tied into a mesh using ordinary knitting wire, creating cells of 200*200 or 150*150.

Sometimes welding is used instead of wire, but this is a solution only if you have welding machine and you have good skills in this area. Welding reinforcement rods can greatly thin them at the welding points, which can subsequently lead to a violation of the integrity of the structure.

The reinforcement in the mesh should be without breaks, but if the length of one reinforcement is not enough, additional reinforcement should be tied with a noticeable overlap of at least half a meter. The joints should be staggered, and the edges of the meshes should be connected in a U-shaped format. If it is necessary to bend the reinforcement, this should only be done using mechanical means, without heating the rods. Heating can affect the structure of the metal, which can subsequently simply burst. Places of special loads are reinforced with additional rods, so it is very important to take into account the location of heavy elements and clusters of holes, which also need to be reinforced. The upper mesh should be reinforced above the load-bearing walls; volumetric reinforcements are also required in places where they support columns.

It is best to fill the finished mesh of reinforcement with a concrete pump. For small amounts of work, you can do it yourself, but in this case, you must organize a quick supply of ready-made concrete and mix it at least using a manual concrete mixer, that is, you will need at least 2-3 assistants. After pouring, it is imperative to compact the concrete - large areas To do this, use a deep vibrator; at home, you can get by with rhythmic and frequent tapping of a hammer on the formwork or still open mesh elements.

When concrete hardens, it shrinks noticeably, and if it dries too quickly, the shrinkage increases, which can cause microcracks to appear. Therefore, after pouring concrete, the monolithic slab should be watered, especially in hot weather. Avoid a direct stream; try to spray water over the entire ceiling. Quite often, in order to avoid cracking of concrete, a polymer mesh is laid on the bottom layer, on top of which the main structure is made. Polymer mesh is also used to reinforce concrete screeds, when the use of wire or reinforcement is simply impossible.

During the construction of houses, garages, cottages, and other structures, a stage comes when it is necessary to perform floors. The ceilings can be interfloor or ceiling, made of wood, using wooden beams, using concrete slabs or by pouring concrete. Each of these floor installation methods has its own legal right to exist, supported by the economic feasibility of using a specific option in each individual case. In this article, we wanted to talk about a specific case, namely the pouring of concrete interfloor (ceiling) floors. Before we talk about the methods of installing these floors, we wanted to touch on the topic of the use and installation of poured concrete floors, let's talk about their feasibility and advantages relative to other similar floors.

Advantages of poured concrete floors (monolithic concrete floors)

First of all, monolithically poured concrete floors should be considered as an alternative to slab floors. Wooden floors are too different from concrete-monolithic floors, first of all in price, monolithic ones are much more expensive, secondly, in strength, they are much stronger, thirdly, in durability and other not so significant differences. That is why it is worth comparing, first of all, with slab floors. Thus, in some cases, monolithic (concrete) floors are cheaper, which is an undeniable advantage, and at the same time they have similar strength properties. Another important advantage is that the fillers monolithic concrete ceilings can be made of any complex shape, almost anywhere, which is sometimes impossible for standard, factory-made concrete products.

Example of installation of concrete, monolithic floors

Next, we present specific example installation of concrete floors. IN in this case, this is a particular example, we will describe possible improvements that could be made to improve the quality of the overlap as alternative solutions. So, first of all, it is necessary to build a support for the poured concrete mixture and formwork.

After this, it is necessary to install the fittings.

It is best to carry out installation using mounting wire and lay two layers of grating.

One reinforcing grid should be at the bottom, the second, laid through the “frogs,” should be at the top. Such a monolithic floor will more correctly perceive the bending load, due to the operation of the reinforcement in the most stressed places, which will significantly increase the strength of the floor.

Afterwards, we begin pouring concrete. It is best to buy the planned volume of concrete for this operation in order to carry out the entire pour at one time, since only in this case can you guarantee equal strength of the entire monolithic floor structure.

Also, you should not pour all the concrete into one place to prevent subsidence and collapse of the floor formwork. It is best to supply the concrete mixture evenly over the entire area; in extreme cases, quickly distribute it over this area using any alternative method.

The final stage will be holding the concrete mixture under certain conditions (temperature and humidity), which will ensure technological hardening of the mixture and its quality.

So, you can read more about the process of hardening the concrete mixture in the article “How to pour a concrete floor screed.” Afterwards we dismantle the formwork, and our concrete floor is ready for use.

Calculation of formwork holding monolithic, concrete floors during pouring

Someone with a certain amount of construction knowledge can install a concrete floor based on his life experience, or, as they say, “by eye.” We want to offer you another, albeit not an institute calculation, but which to a high degree will become yours successful pledge successful work.

Calculation of formwork for this type of floor should be done according to three main parameters:

1. For the longitudinal load on the supports holding the formwork. Initially, it is necessary to calculate the cross-section of the supports for the holding formwork. Is this value not so critical? as subsequent parameters, which is why you most likely will not have problems with it. σ = N/F ≤ Rс where σ are internal normal stress, arising in the cross section of a compressed beam, kg/cm2; N – mass of our formwork and poured mixture, kg; F is the cross-sectional area of ​​the column cm2; Rc is the calculated resistance of wood to compression at the yield point, kg/cm2. (For pine, the calculated resistance is 140 kgf/cm2)

2. For bending supports under load. Also, do not forget the factor that the bending rigidity of the beam changes with its length. So, as the length of the holding beam increases, its flexibility also increases, and its rigidity decreases accordingly. In order to take this factor into account, it is necessary to take the cross-sectional area of ​​the beam from correction factor φ

σ = N/φF ≤ Rc

the coefficient will depend on the ratio of diameter to length; to facilitate calculations, it can be taken from the series below

L/d = 5 10 20 30 40 50
φ = 0.9 0.85 0.5 0.25 0.15 0.08

3. To ensure the integrity of the formwork base The last thing you should pay attention to is the strength of the retaining formwork onto which the concrete will be poured. So the formwork must withstand not only the static mass of concrete, but also the dynamic load during its pouring. Also, do not forget about the possible temporary overflow of concrete to a specific local place and the weight of the worker who will distribute the concrete in it. As a result, the permissible thicknesses of plywood formwork, with a margin of 1.5, with a span of no more than 1 m, can be taken from the series below.

Plywood thickness 18 mm 21 mm

Thickness of the poured concrete floor layer up to 9 cm up to 12 cm

Now you can not only pour the concrete floor, but also pre-calculate the auxiliary technological elements for its installation.

Comments:

It is possible to make a durable monolithic floor with your own hands if you have certain knowledge, skills, necessary materials and tool. The installation process itself is divided into three main stages: installation of formwork, reinforcement of the floor and concreting (final pouring).

A monolithic floor slab is an ordinary concrete slab reinforced with reinforcement. The dimensions of the slab are calculated based on the construction project data. The ratio 1:30 is taken as the average value, i.e. When constructing a two-story building with a span height of 3 m, you will need to install a 0.2 m wide floor. For non-residential premises A minimum floor thickness of 12-15 cm is acceptable.

Installation of formwork

Installation of formwork is the most labor-intensive stage in the manufacture of reinforced concrete slabs.

When installing a monolithic floor with your own hands, you should take into account that the formwork must have a high margin of safety in order to withstand the weight of the poured concrete and not deform.

Materials required for installation and production of formwork:

Figure 1. Formwork diagram: A - step of the crossbar, B - step of the transverse beams of the formwork, C - step between the racks.

• wooden beam with a section of 100x100 mm;
• moisture-resistant (laminated) plywood 20-25 mm thick;
• wooden boards (50x150 or 70x200 mm).

Basic tools:

1. Telescopic racks serve as support for the formwork and allow you to adjust the height of the structure.
2. Uniforks (universal forks, fork heads, “crown”), necessary for inserting longitudinal load-bearing beams.
3. Tripods supporting telescopic stands to avoid distortion.

The use of racks is more reliable than homemade wooden supports, each can withstand a weight of 900-2000 kg, they ideally regulate the height of the formwork and have a high resistance to deformation. If necessary, stands can be rented. For each telescopic stand you will need 1 tripod and 1 unifork.

Additional tools:

• level;
• axe;
• hammer;
• level;
• wood hacksaw;
• nails.

The formwork is installed after the walls of the basement, first or second floor of the building are raised to the height specified in the project. The layout of the formwork elements is shown in Fig. 1, where:

1. Distance “A” - crossbar pitch (distance between longitudinal beams);
2. Distance “B” is the step of the transverse beams of the formwork;
3. Distance “C” is the step between the posts, depending on the cross-section (for wooden posts).

Stages of installation of floor formwork:

1. Using a level or level along the perimeter of the span, the level of the bottom of the future floor is measured. This is necessary to calculate the height of the formwork.
2. Telescopic stands are installed. First, along the edges of the room at a distance of 20-25 cm from the walls, then in the middle with a step between racks of 0.8-1.2 m. If wooden racks are used, they must be made of solid wood.
3. Crossbars (channel, I-beam, longitudinal beam), designed to hold the formwork table, with a distance between them of 0.6-1.8 m (depending on the thickness of the crossbar).
4. On top of the longitudinal beams (crossbars) are laid cross beams in increments of 0.4-0.6 m.
5. Sheets of plywood are placed on the cross beams. When using edged boards instead of plywood, they fit closely to each other. The edges of the horizontal formwork should rest against the walls, leaving no gaps.
6. Compliance with the horizon is checked.
7. The boardwalk is covered with dense polyethylene.
8. A vertical formwork fencing is installed, taking into account that the edge extends onto the walls at a distance of 150-200 mm. When installing the “side”, the corners are carefully adjusted.

The formwork should be dismantled no earlier than a month after pouring the concrete, taking all necessary precautions.

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Monolithic floor reinforcement

To strengthen a monolithic floor with your own hands, to make it resistant to bending, fracture and compression, use rod reinforcement. To tie the reinforcement mesh you will need:

• hot-rolled steel reinforcement with a diameter of 10-16 mm (class A400, A500);
• bending machine for reinforcement;
• knitting wire with a diameter of 1.2-1.5 mm;
• stands for rods (chairs);
• hook for knitting reinforcement.

The reinforcement is made in two mesh layers with a cell size of 150x150mm or 200x200mm.

Stages of reinforcement of a monolithic floor:

1. Using soft knitting wire and a hook, reinforcement meshes are tied together.
2. Clamps (chairs) are placed on a plywood base at the rate of 4-6 pcs. per m2 area.
3. The first connected reinforcing mesh is laid on the clamps (it should be located 2.5-5 cm above the lower plane of the concrete floor).
4. Vertical clamps made of bent reinforcing rod are laid on the first layer of reinforcement, with an installation step of 1 m. The clamps are arranged in a checkerboard pattern.
5. A second reinforcing mesh is placed on the vertical clamps, located 2.5-5 cm below the upper plane of the concrete slab.
6. End clamps are installed, as well as connectors for the upper and lower reinforcing mesh. Installation pitch 400 mm.

If it is necessary to splice reinforcement rods, they are knitted overlapping, with an overlap of at least 40-50 cm. The reinforcement frame must protrude beyond the edges of the concrete (from the end) by at least 15 cm on each side and lie on the load-bearing beams. During pouring of concrete, the entire reinforcement structure must be rigid and motionless.

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Concreting (pouring) the floor

To prepare high-quality concrete you will need:

• cement grade 500;
• crushed stone without organic impurities, fraction 5-20 mm;
• clean sand without clay impurities;
• water.

Recipe for producing classic concrete:

• 1 part cement;
• 3 parts sand;
• 3 parts crushed stone;
• the amount of water required to obtain a solution of the desired consistency.

For pouring large volumes of concrete, a concrete pump is best. Filling a reinforced frame with concrete manually using a shovel significantly increases the pouring time and greatly reduces the strength of the resulting monolithic floor.

Concrete should be poured evenly, in layers, to prevent distortions of the formwork, and at one time. To compact each layer, vibration testing of the concrete should be carried out. Vibration allows you to:

• distribute and place crushed stone more densely in concrete;
• distribute the load evenly in the cement mortar;
• remove air bubbles, thereby reducing the number of voids in the slab after hardening;
• fill all cracks and gaps with concrete as much as possible;
• do liquid concrete more manageable and amenable to final horizontal alignment.

For vibration work, you can use a vibrating screed or a deep vibrator with a vibrating mace. Vibration should not last longer than 20 seconds. The total pouring time should not exceed 3-4 hours. The entire floor should be poured at one time. After pouring is completed, the slab should be pulled out and leveled until smooth.