When arranging a pitched roof, the installation of the rafter system cannot be done directly on the walls of the building. Additional element, which absorbs the loads from the rafters and transfers them to the walls, will be the Mauerlat. Usually this is a special beam that is laid around the perimeter of the walls. Since it takes a serious load from the roof, it is very important to securely fix the Mauerlat to the wall. In the case of brick or concrete walls everything is simple and clear. But how is the Mauerlat attached to aerated concrete without an armored belt, since the aerated block itself is quite loose and porous, and therefore cannot provide a strong fixation of the fastener? This is exactly what we will talk about in our article.

Functional purpose of the Mauerlat

Typically, the same material is used to make the Mauerlat as for the rafter system. Most often it is made from wooden beams. However, if the rafter system is made of metal, then this structural part can be made of a channel or I-beam.

Typically this element is made from the following materials:

• Wooden beam with a section of 100x100 mm, 150x150 mm or 200x300 mm. The timber is made from hardwood and undergoes mandatory antiseptic treatment. The product is laid around the perimeter of the walls of the structure. The joints are fixed with nails or a straight lock. Most often used in private construction wooden structure roofs.
• Less commonly, rolled profiles are used for these purposes - a channel with a U-shaped cross-section or an I-beam with H-shape sections. The profile height is determined by calculation and can be in the range of 70-120 mm.

A beam or steel beam is attached to the walls. In this case they can be used different ways fastenings Next, the rafter legs rest on the mauerlat. They exert a load on this element, which in turn, evenly distributing it, transfers it to the walls of the building. In addition, this beam keeps the rafter system from shifting.

Important: since aerated concrete does not tolerate long-term point loads and gradually collapses, it is recommended to erect a monolithic reinforced belt along the top of the walls before laying the Mauerlat.

However, there are ways to install this structural element on aerated concrete walls without an armored belt. It is also worth remembering that the upper edge of the Mauerlat should be located at a height of at least 30-50 cm from the surface of the ceiling. This will ensure effective ventilation of the under-roof space, and will also facilitate inspection and repair of roof structures.

Mounting methods

Attaching a Mauerlat to aerated concrete is much more difficult than to a brick wall

Attaching the Mauerlat to aerated concrete is much more difficult than to a brick wall. As a rule, this product is laid at a distance of 50 mm from the outer edge of the wall. The following fasteners can be used to secure the Mauerlat:

• steel wire;
• anchor fasteners built into the masonry;
• special chemical anchors;
• steel studs.

Important: to attach the support beam to a reinforced belt or brick walls anchors are used.

After installing the beam, the rafter leg is pulled to the wall using a twist made from twisted metal wire with a diameter of 3 mm. To fix the wire 6 cm below the beam, a steel short is mounted. Instead, the wire can be fixed to the floor slabs. During installation complex roof It is recommended to make sure to use a reinforced concrete belt, which will give the building additional rigidity and more evenly distribute the load from the roof onto the walls of the house.

For tying individual parts Mauerlat into a single structure uses an oblique cut, followed by fastening with nails, screws or bolts. To strengthen the corner parts of the structure, steel plates and brackets are used.

Using wire to secure beams

If wire is used to fasten the Mauerlat, then this must be taken care of at the stage of laying the walls. The wire must be laid in the wall tub when performing the last few rows. In this case, the following sequence of actions is followed:

1. When laying aerated concrete blocks, two or three rows before the end of the walls, a steel wire with a cross-section of 6 mm is laid between the elements, which consists of several thinner wires twisted together.
2. In this case, the middle part of the fastener is inserted into the masonry. Its ends should protrude from the walls. The length of these ends should be such that the wire can be freely wrapped around the timber being laid.
3. The number of wires used must be equal to the number of rafters being installed.

Fixation with pins

Fastening the Mauerlat to a wall made of aerated concrete with studs is allowed when installing light roofs on small houses. The materials used to form the roofing pie must be as light as possible and not transfer significant loads to the remaining structural parts of the building.

This technique is ideally suited in cases where it is not possible to arrange an armored belt. In such a situation, the timber itself will serve as a reinforcing belt. This method causes rather controversial reviews from experts, but in practice it has proven itself very well, providing high reliability and roof stability.

To fix the timber to aerated concrete you will need the following elements:

• studs marked SRT-12, called “dovetail”;
• wooden beam with a cross section of 20x30 cm (the dimensions of this element depend on the thickness of the external walls).

We carry out the work in this order:

1. We drill holes in the aerated block walls in increments of 100-150 cm.
2. We insert pins into the holes and fix them with cement laitance or non-shrink mortar.
3. Next you need to perform waterproofing. To do this, two layers of roofing material are laid on the walls. At the location of the studs, holes must be pierced in the material to ensure a tight fit to the walls. Waterproofing will protect the wooden beam from saturation with moisture and subsequent rot, which can come from the walls.
4. With the same step as the studs were installed, holes of a diameter suitable for the studs are drilled in the Mauerlat.
5. Then the timber is placed on the studs over the waterproofing, washers are installed and tightened with nuts.
6. After installing the beam, the ends at which the individual fragments of the beam are joined are tightened with forged steel brackets.
7. Now you can begin installing the rafter system.

If the studs will be mounted in an armored belt, then we carry out the work as follows:

1. Before pouring the armored belt, studs are placed in it with a pitch of no more than 100 cm.
2. They are attached using a knitting wire to the reinforcing frame of the belt. Instead of wire, you can use plastic ties to secure the studs.
3. The accuracy of the installation of the studs horizontally and vertically is checked.
4. Concrete is poured into the armored belt formwork.
5. After it hardens, the prepared timber is put through the holes onto the protruding ends of the studs and pulled to the surface with nuts.

Chemical anchor

This product is also called liquid dowel, injection mass or glued-in anchor. Essentially, it is an adhesive with high adhesive characteristics, which is made on the basis of a synthetic polymer resin. Thanks to the chemical anchor, it is possible to firmly fasten the metal rod and the base.

Important: unlike other fastening elements, the liquid dowel does not create expansion stress in the material, which is especially dangerous for fragile aerated concrete at the edges of walls.

Unlike mechanical anchors, the fixation of which is based on the use of friction forces and expansion of the dowel made of polymers, a chemical anchor is fixed due to the fact that the glue penetrates into the pores of aerated concrete to a considerable depth and firmly secures the rod in the wall.

Installation of a chemical anchor is performed in the following sequence:

1. First, a hole is drilled along the anchor. However, its size should be slightly larger than for a regular anchor bolt.
2. Using a special brush or compressed air, dust, debris and metal chips are removed from the channel.
3. A special chemical adhesive is poured into the hole prepared in the wall.
4. After this, a steel rod is inserted there - a threaded rod M 12-14. You can also take a piece of reinforcement of a suitable diameter for these purposes.
5. The adhesive composition gains the required strength in 20 minutes, provided that the ambient temperature is approximately 20°C.
6. After the chemical composition has hardened, the rod is securely fixed in the wall. Moreover, the fastening strength is much higher than that of the mechanical method.

Advantages of using liquid dowel:

• The service life of such fasteners is more than 50 years.
• This method of fixation can be used on the edge of walls without fear that it may crack.
• The fastener has fairly high chemical resistance.
• Fastening can be carried out on damp material, that is, installation can be carried out even in rainy weather.
• Work on installing the Mauerlat and arranging the roof can be carried out without using reinforced belt, since a chemical anchor is fixed much more firmly in a fragile material than a mechanical dowel.
• This method is ideal for working with aerated concrete.
• The depth of the hole may be less than when installing a mechanical anchor, which must be buried 2-3 rows of masonry.

The only drawback of this method of fixation is that welding cannot be performed with a rod attached to a liquid dowel, since heating polymer material is destroyed, the fixation strength decreases.

Mechanical anchor (anchor bolt)

This is a fairly common way of fixing timber to walls. The anchor bolt consists of the following parts:

• external spacer part;
• internal threaded rod.

Fixation occurs due to the fact that when the nut is screwed onto the rod, the spacer structure is deformed in such a way that it reliably fixes the product in the hole drilled in the wall.

The installation of a mechanical anchor is carried out in the following order:

1. Prepared timber is laid along the perimeter of the walls.
2. Next, holes are drilled along the entire length of this product for installing anchor bolts. The hole spacing is 1 m. It is important to ensure that the installation locations of the anchors always fall on the corners of the building and the junction of the two ends of the beam.
3. After this, using a drill, holes are drilled in the walls through the holes prepared in the Mauerlat to a depth equal to the length of the anchor. At the same time, it is not allowed to make the depth of the anchor less than 2 or even 3 rows of masonry.
4. An anchor bolt is installed in the hole. For these purposes, it is better to take products with a length of at least 50 cm with an M 12 or 14 thread.
5. After this, put on the washer and screw the nut tightly. As a result, the steel or plastic dowel expands so that it is firmly pressed into the material and fixes the bolt in the wall.

One of the most important nuances technology for building a house from aerated concrete is the fastening of the Mauerlat. The characteristics of the blocks do not allow them to withstand high point loads; without taking structural measures, the walls will simply collapse. Correctly performed fastening involves laying an armored belt; it is not recommended to skip this stage. If it is impossible to organize it, the Mauerlat comes into direct contact with the wall and is fixed with wire, anchors, pins or dowels. The method is determined in advance; in the absence of experience, this type construction work It's better to leave it to specialists.

Possible fastening methods

Depending on the type of strapping scheme, one of two options for attaching the Mauerlat to aerated concrete is selected: pouring a monolithic reinforced concrete belt around the entire perimeter of the building or placing fixing elements directly into the masonry or blocks. The first method, in addition to ensuring maximum reliability, helps to redistribute loads, levels the walls and protects them from deformations, including shrinkage. The presence of an armored belt is mandatory when carrying out construction in areas with seismic activity, erecting houses made of aerated concrete over one floor, using heavy roofing materials, complex roof shape.

Standard instructions for laying it include the following steps:

• Preparatory: calculation of fasteners and selection of the interval between them. The main guide is the rafter placement diagram: if the number is equal, the attachment points to the Mauerlat should not coincide with the places where the studs are screwed.
• Laying U-shaped blocks on top of the last row around the entire perimeter of the aerated concrete wall. They act as formwork, the recommended width is from 25 cm.
• Assembly of a reinforcing frame from rods with a thickness of 10 mm. At this stage, it is planned to lay pins to fix the Mauerlat at intervals of no more than 1 m, strictly vertically, tied with wire to the main rows. Special attention is given to the corners, in these areas the metal rods are bent to a length not less than the width of the belt. Similar actions are repeated around the entire perimeter load-bearing walls, including gables and partitions.
• Organization of an insulating layer of compacted polystyrene foam. It is placed closer to the outer edge of the aerated concrete wall.
• Filling the internal cavity with concrete with a strength grade of at least M200, compacting, removing excess and carefully leveling the top layer. Cover with polyethylene and standard moisture care during the first days.

You can begin the next stage of tying the Mauerlat to the aerated concrete walls in a week. All formwork structures are removed (they are used when pouring a monolithic reinforced concrete pad along the entire perimeter and width, this design is typical for brickwork, but is sometimes used for houses made of gas silicate). Next, 2 layers of waterproofing are laid or coated on top of the upper side in contact with the future Mauerlat; this stage cannot be skipped. Attachment points are marked on a wooden beam treated with antiseptics and fire retardants and well dried. The easiest way to do this is by placing it on the armored belt over the studs and hitting it with a sledgehammer; holes are drilled according to the diameter of the rods (at least 14 mm). After this, all that remains is to attach the Mauerlat to the aerated concrete wall and tighten it with nuts or washers.

The final stages of the work are difficult to complete on your own; at least 2 people will be required. In addition to main walls, the armored belt is mounted on any areas on which roof elements rest (for example, ridge posts or beds). If you have no experience, you should watch video instructions on the topic “how to properly attach the Mauerlat.” If you need to eliminate errors that occurred during the laying process, it is better to contact specialists, at least for advice. Installation of rafters is possible only after completion of all work on fixing the Mauerlat and checking the quality of connections.

How is the Mauerlat attached to the wall in the absence of an armored belt?

Laying a monolithic tape with your own hands is not always possible; in some cases, they resort to other methods of tying the timber. The easiest way is to lay steel wire 3-4 rows before the top between the blocks. Its length is selected taking into account the cross-section of the Mauerlat: when folded in half, it should be enough to girth and twist. The pitch depends on the distance between the rafter structures. This option is often used when attaching timber to a wall. one-story house from aerated concrete.

For light and small-sized buildings, it is also suitable to attach the Mauerlat to threaded rods made of galvanized or of stainless steel. They are installed in the masonry 1-2 rows before the top edge, the minimum permissible depth of such products into a wall made of aerated concrete is 2 times the height of the block. The standard length of studs is within 1 m, diameter is from 8 to 24 mm. If necessary, protruding areas are then cut off.

Fastening the Mauerlat beam with wooden dowels is possible both when laying an armored belt and without it. They are long corks treated with antiseptics and well dried. They are mounted into a wall made of aerated concrete closer to the upper edge and connected to the Mauerlat using brackets. Alternative option is their laying between the blocks, the number of pieces is not less than the number of rafters.

High reliability of fastening is ensured using anchors: mechanical or chemical. In the first case, the method consists of screwing expanding dowels with a cross-section within 12-14 mm into aerated concrete. The second is in application. chemical anchors(capsule or in the form of a tube with compositions based on polymer resins). The minimum depth of the hole to be laid is 2 rows of masonry.

The main advantage of anchoring is the ability to secure the Mauerlat without complex organizational measures in the process of laying gas blocks; it is quite easy to do it yourself. Nevertheless, top scores observed with maximally stationary hardware, that is, either laid simultaneously with an armored belt, or fixed with the help chemical compositions(in the latter case, welding work near the connections is prohibited). The disadvantages of this method include its high cost: of all the technologies for fastening without an armored belt, anchoring will cost the most, and the more reliable it is, the higher the final costs will be.

Violations of the Mauerlat fastening technology when doing DIY work include:

• Lack of waterproofing layer between the timber and the top of the wall. Preference is given to modern bitumen-polymer mastics, budget option is roofing felt, polyethylene film is not suitable for these purposes due to low strength. The minimum number of waterproofing layers is 2.
• Planting a mauerlat that has not been treated with antiseptics (the contacting side remains unprotected) or the use of wet wood.
• Installing anchors or studs at an angle makes the connection unreliable.
• Incorrectly selected reinforcement for the frame, lack of overlaps (the recommended minimum if it is necessary to extend the rods is 20 cm), close contact of the metal to the walls of aerated concrete (plastic stands are well suited to provide the required 5 cm).

When using raw wood, the Mauerlat is fixed with a nut, the reliability of the fastenings is periodically checked, and if necessary, they are tightened. This operation is carried out at least once a year for 4-5 years, until the end of the shrinkage processes. A completely dry and established beam practically does not need tightening; its inspection is carried out for preventive purposes.

How to attach the Mauerlat to aerated concrete without an armored belt?

On manufacturers' websites there are conflicting statements regarding the need for building a building from aerated concrete blocks. Some argue that they are quite capable of withstanding the expected load. Others, on the contrary, suggest playing it safe. However, all manufacturers and builders are confident that porous materials react negatively to point loads.

Therefore, it is necessary to distribute it evenly. If for any reason the installation of an armored belt is not possible, it is necessary to use. This will extend the life of the structure.

The Mauerlat is most often made from the same material as the rafters - metal (channel, I-beam) or wood (timber)

This is a special design that is used to distribute the weight of the roof evenly across the walls. As a rule, it is made of wooden beams. It is to the Mauerlat that the rafters are attached to make the roof stable. The durability and reliability of the entire structure depends on the quality of installation.

The Mauerlat can be metal, but only if steel rafters are used. However, such structures are rare, since the cost of construction increases significantly. In addition, fastening steel parts is much more difficult than wooden ones.

Mauerlat functions:

• uniform distribution of the weight of the roof over the walls;
• reliable fixation of the rafter system;
• protection and prevention of point loads on aerated concrete blocks.

The minimum size of timber used as a mauerlat should be 10*10 cm. However, to ensure best quality For clutches, it is advisable to use a material with a larger cross-section. It is permissible to use a log, but it is necessary to cut off the side that will be adjacent to the aerated concrete.

The rafter legs at the points of support transfer the load to the mauerlat, which, transforming and distributing, transfers it to the walls

Hardwood timber performs these functions best. In order for it to last longer, it must be treated with antiseptics and impregnations that prevent rotting and insect damage. The beams must completely and evenly cover the walls. They are fastened together with nails or a straight lock. Due to the fact that the cross-section of the wooden material is smaller than the width of the gas block, the Mauerlat is placed on the inside of the walls.

The distance to the outer edge must be at least 5 cm. Laying bricks on the outside of the building is also permissible. Between aerated concrete wall

and the wooden mauerlat should be a waterproofing layer.

Methods for attaching the Mauerlat The Mauerlat can be attached directly to aerated concrete or using an armored belt. There are such connection methods wooden beam

• with wall:
• using steel wire;
• using anchors;

stiletto heels.

When using any of the above methods, you must ensure that the fastening is of high quality and reliable. Also, during installation, structural shifts should be avoided.

In private housing construction, wooden beams are the main material used to work on the mauerlat

Steel wire can securely fix the Mauerlat quite reliably. It is woven into the masonry several rows before the top of the wall. 2-4 blocks in height is enough. The middle of the wire must be fixed, and its length must be sufficient not only to the top of the wall, but also to attract and fix the Mauerlat. The number of links is not limited. But usually there are as many of them as there are rafter legs.

Anchoring

In this case, it is advisable to use an armored belt. Anchors allow you to securely fix the rafters, but create a point load, which is extremely undesirable for aerated concrete blocks. Under its influence, the porous material quickly collapses. The armored belt allows not only to protect blocks from point loads, but also to increase the rigidity and strength of the entire structure. Also, by pouring concrete, you can level the top of the walls horizontally. This will make it easier to install the rafters later.

Anchors are installed at the pouring stage. They are fixed in the gutter, which will be filled concrete mixture using wire. It is necessary to ensure that the anchors are level. To do this, you can additionally tighten the cords. Anchors should be positioned strictly vertically. The number of fastening units is not regulated, but their number must be no less than the number of rafters. When the concrete hardens, they will literally be walled up in it.

The fasteners increase the load-bearing characteristics and strengthen the strength of the nodes, eliminating the displacement of the rafters under the influence of high loads

The beams are laid on the finished armored belt with bolts. By wooden material knock with a hammer or mallet. Dents from anchors form on the timber. Holes must be drilled in these places. You need to ensure that they are level and do not deviate from the vertical. Then the timber is laid on the concrete so that the anchors fall into drilled holes, and secure with nuts and washers.

Small concrete pads can replace a full armored belt. They are installed in places where the Mauerlat is attached to the wall. They also distribute the load more evenly and prevent the destruction of gas blocks.

Attention! Between the reinforced concrete strip and wooden beam It is advisable to lay a layer of waterproofing. You can use either special mastics or simple roofing felt.

Using metal pins

Fastening the Mauerlat to metal studs can be done in 2 ways: by walling them up in the wall or filling them with concrete in an armored belt. In order not to make a mistake with deepening the fasteners, you can use the following rule: it is inserted into the frame to a depth of 2 Mauerlats. If a 10*10 cm beam is used, the pin should extend 20 cm into the wall or reinforced belt.

Fasteners are mounted into the wall 1-2 rows before the end of the walls. It must be taken into account that the length of the pin should be enough not only for the blocks, but also for the Mauerlat. There should also be a small margin left for tightening the nuts and washers.

The ridge beams, in turn, rest on the permanent wall structures (gables) and (additionally) on the racks. Layered rafters do not require transverse ties and struts, which can significantly reduce the useful volume attic floor under the roof. With a house width of gable roof from 8 to 10 meters is used either truss structure with additional purlins, struts or in the form of three-hinged trusses. However, the installation of layered rafters requires some experience and proper design in order to avoid the occurrence of bursting loads. The majority of self-builders, cobblers and guest workers in Russia usually prefer the device of classic spacers rafter schemes, where the top and bottom of the rafters are connected by a hinge with one degree of freedom (or rigid pinching), then the main load is transferred to the external counter of the walls of the house made of aerated concrete, and accordingly, bursting loads applied to the walls arise. In this case, it is necessary to install a rigidly fixed mauerlat, directly connected into a single contour along the perimeter of the building, or rigidly tied to a single contour of the supporting monolithic reinforced concrete piping circuit. Therefore, we recommend that when independent design and the construction of a house made of aerated concrete in all cases should be carried out along the upper edge aerated concrete walls(not only external ones, but all interior walls) monolithic reinforced concrete strapping belt, in which T- or L-shaped anchors with M12 threads are placed along the outer contour in increments of 1 meter for a rigid connection with a wooden beam with a mauerlat (100 x 150 mm, or 150 x 150 mm) on which they will be lean on the rafters.

This design will allow you to avoid problems with wall expansion, even if you or your builders assemble the rafter system incorrectly, and it will create expansion loads on the walls. Below we will look at how to properly install a rafter system that does not create bursting loads on the walls of a house made of aerated concrete.

Diagram of the installation of a monolithic reinforced concrete strapping belt for fastening the Mauerlat

Before installation, the Mauerlat is treated with antiseptics (ХМ-11, ХМББ) and laid on waterproofing made of bitumen-polymer roll waterproofing material (not roofing material). According to the pitch of the anchors, holes are drilled in the Mauerlat and the Mauerlat is installed in place. A washer and nut are placed on the threaded rods of the anchors and tightened until they stop. If you use a common "tree" for Russia natural humidity"(that is, raw - which no self-respecting consumer would buy in any civilized country), then you need to provide access to the Maueralt fastening in order to tighten this nut once a year for 5 years (the most intense shrinkage is observed in the first year), until the wet wood will dry out and shrink. In the case of a braced rafter structure or if you do not know whether the rafter structure will be braced or non-braced, it makes sense to build a buttress from a sawn aerated concrete block on the outer side of the mauerlat (through a waterproofing gasket). The diagram below shows the method of fastening rafters for a traditional spacer scheme, with one degree of freedom for the end of the rafter leg.

What does this mean? Rafter leg in this case it is fixed by two steel plates (a steel angle and a strip connecting element) and a wire tie, which prevent rotation in the Mauerlat-rafter hinge. Sliding in this hinge is also impossible due to the rigid fastening of the rafters with an angle and flat metal, coupled with a support bar hemmed from the bottom of the rafters. If the top of the rafters with such a fastening unit is tightly pinched, or the rafters rest against each other, then with this design the thrust load will be transferred to the walls of the house.

Constructive methods of attaching maueralat to the wall of a house made of aerated concrete

Mauerlat is a design designed accept and evenly distribute the load, created by the roof and perceived by the walls. With its help, the stability of the roof is ensured, provided that the Mauerlat is fastened according to all the rules. To do this, you need to know what a Mauerlat is, how it is attached to the aerated concrete wall, and also in what sequence the work should be performed.

Do you need a Mauerlat?

Without a Mauerlat it is possible to install roofing systems on frame houses, as well as buildings erected from timber and logs. They have the function of this structural element can make the top crown of logs or the top beam. For buildings made of aerated concrete, this is unacceptable, and therefore the installation of a Mauerlat must be done without fail.

With it you can:

• significantly strengthen the building box;
• increase the rigidity of the installed roof;
• align the upper crown of the wall in a horizontal plane;
• ensure fastening of the roof structure and walls of the building.

The thickness of the Mauerlat depends on design features mounted roof. Most often, timber with dimensions of 150 x 150, 150 x 100 or 80 x 180 mm is used for its manufacture. It is also acceptable to use logs that have been cleared of bark and cut on one side. Trimming is done to ensure maximum adherence of the structure to the wall surface.

The moisture content of the wood used must be appropriate regulatory requirements. When using “raw” wood, it must be provided the ability to adjust the anchor nut once every five years. After the timber has dried, the shrinkage of the wet wood will occur less intensely, and therefore the nut will need to be tightened less frequently.

The prepared wood undergoes special treatment antiseptic composition to protect the structure as much as possible from rotting and insect damage. Before laying the log should be wrapped waterproofing material, for example, bitumen-polymer. It is better to avoid using roofing felt.

If a metal frame is mounted, rolled metal is used to make the Mauerlat: channel or I-beam. It can be treated with anti-corrosion compounds.

Features of installing the Mauerlat

The Mauerlat must be laid in such a way that there is some distance left to the outer edge of the wall. As a rule, about 5 cm. Sometimes it is provided protrusion into which the mounted structure should rest. Subsequently roofing system will have to be attached to this structure.

To increase the service life of a structure made of wood, waterproofing must be provided. For this, roofing felt or any other waterproofing material is used.

Methods of fastening to aerated concrete walls

The preferred option is to install the element along the entire perimeter of the wall. To connect individual elements into a single whole, it is advisable to use straight lock, the dimensions of which directly depend on the geometric parameters of the timber used. For reliability, nails are additionally driven into the lock to form a rigid, integral system, to which the rafters are subsequently attached.

To secure the Mauerlat, you can use several methods:

• chemical;
• mechanical.

In the first case it is used special fastening capsules. Chemical substance, penetrating inside the material, ensures reliable fixation of the Mauerlat. At the same time, the condition of the top layer improves and the degree of heat and waterproofing increases. The capsules used for fastening are affordable.

To make a Mauerlat you must only use quality materials. The wood should not have knots. The waterproofing layer must not be damaged, which is achieved by using a special tool.

When mechanically fastening it is necessary to follow a certain procedure:

1. dowels are inserted into holes prepared in advance;
2. the fastening element is screwed in;
3. the teeth of the harpoon are firmly pressed into the aerated concrete;
4. surface expanded;
5. fastening has been done.

The Mauerlat must be fastened in such a way that adjacent links were not connected to each other. This improves the stability of the structure. However, mechanical fastening involves the creation of an expansion force, which can cause some problems at the edge of the structure.

Fastening with anchor bolts and armored belt

For buildings built from aerated blocks, armored belt is required, since this one construction material not strong enough, which can cause certain difficulties when installing fasteners, especially anchor bolts. Therefore, the question of whether a Mauerlat is needed is not relevant in this situation: you simply cannot do without it.

Fasteners for the Mauerlat must be laid in advance. To construct a reinforced belt, it is advisable to use U-shaped blocks, with which you can form a characteristic groove around the entire perimeter outer wall. To avoid the formation of gaps, the corner blocks are sawn through.

The reinforcement frame is assembled using 12 mm reinforcement, which is tied with 6 mm jumpers. Threaded anchors are attached to the frame placed inside the gutter. They must take a certain spatial position, which is controlled using a stretched fishing line or cord. The anchors are placed at right angles to the mauerlat as close as possible to the top beam.

Fastening points should be located along the entire perimeter of the wall. Their number directly depends on the number of rafters: at a minimum there should be the same or more. The fastenings must be positioned in such a way as to avoid contact with the rafters in the future. In order to reduce financial costs it is possible to fill not a solid armored belt around the entire perimeter of the wall, but only individual concrete pads.

After the reinforcement cage together with anchor bolts will be placed in a pre-formed trench and concrete will be poured. To form monolithic design The filling process cannot be interrupted. Work must be carried out continuously along the outer wall. The gutter must be filled with concrete in one pass.

After the concrete has completely dried, the anchors will be securely fixed in the specified spatial position. At the same time very it is important to ensure their precise positioning during the solidification of the solution.

As soon as the concrete gains the necessary strength, the beams are laid on the concrete belt and anchors, which should be inside the holes pre-drilled in the wood. Then the nuts are tightened to secure the beams.

To determine the location of the holes in the timber, it is first laid on top of the bolts, and then force impact sufficient to cause dents in the wood. In these places holes are drilled for anchors.