“was perceived extremely negatively - the legacy of Soviet construction had an impact, when, due to violations of technology, poor quality of materials and poor performance of work, flat roofs of high-rise buildings began to leak within a couple of years.
Therefore, in private housing construction, preference was given to pitched or hipped roofs. The situation changed with the advent modern technologies and roofing materials, which made it possible to ensure durable and reliable waterproofing roofs of a house with flat roof.
Flat roofs: advantages and disadvantages
The main reason for the growing popularity of flat roofing was the popularity of modern design trends - project high-tech houses with a flat roof allows you to match the exterior and interior of the building with the style features. Flat roofing is also often used in modernism and minimalism.
However, in addition to its spectacular appearance and visual appeal, it has a number of other advantages:
- speed of roof construction - installation of a flat roof takes less time than a pitched (hipped) roof, including due to the convenience of carrying out work on a horizontal surface
- availability of maintenance - there is no need to install ladders or involve steeplejacks, all work (cleaning drains, monitoring ventilation ducts, cleaning leaves, etc.) can be done independently
- obtaining additional space by arranging a usable roof
- flat roof is ideal for installation and further operation/maintenance of various technological equipment– solar panels, wind generators, heaters, air conditioners, antennas, water collection systems.
A rather controversial issue is the cost of installing a flat roof. On the one hand, the area of such a roof is much smaller than that of a pitched roof, which means that less roofing materials will be required. Yes, and ourselves roofing materials used for flat roof construction are cheaper.
But, on the other hand, the use reinforced concrete floors(in most cases, especially when creating an exploitable roof) creates a significant load, requiring reinforcement of the foundation and load-bearing walls, especially if these are projects two-story houses with a flat roof. Which, while saving money on roof installation, leads to an overall increase in construction costs.
The issue of snow accumulating on a flat roof during the winter also remains ambiguous. Some experts tend to consider this a positive point - snow acts as an additional layer of heat insulation, thereby reducing heat loss. Others argue that snow increases the load on load-bearing elements (and, therefore, this should be provided for in the design), and its subsequent melting can cause a leak in the roof.
Types of flat roof
Projects of houses and cottages with a flat roof can have different kinds roofs:
- operated - involves the regular presence of people on the roof or the installation of heavy objects. Such a roof requires a rigid base (most often reinforced concrete), and the thermal insulation material must withstand serious static and dynamic loads and be strong in compression
- unused - does not provide for a large load, so the rigid (concrete) base can be replaced wooden joists with lathing. To service such roofs, special ladders or bridges are used to reduce the pressure and distribute it evenly over the entire roof area
- inversion - the insulation layer is located above the waterproofing layer, thereby providing it with additional protection from temperature changes, ultraviolet radiation and mechanical influences, the number of freeze/thaw cycles increases. Together, this leads to a significant increase in the service life of the roof. Most often, inversion roofs are used as functional roofs - you can put furniture on such a roof, walk on it, or break it flower beds.
Operable roof: every square centimeter is in use
The ever-increasing cost of modern housing forces us to make the most efficient use of all available space, and house designs with a flat usable roof will help with this. In fact, if we consider projects one-story houses with a flat roof, the owners have at their disposal an additional “seasonal” floor, which makes it possible, for example, to refuse verandas, thereby freeing up additional space on the site.
Decorative garden on a flat roof
Conventional hip roofs, forming an attic or attic, to a certain extent limit spatial possibilities country house. Initially they tried to solve this problem using attic floors, and over time, waterproofing technologies made it possible for houses with a flat roof to appear, and most developers now have a catalog of projects for such structures. Of course, they are somewhat unusual for our traditions, but interesting from an architectural and practical point of view.
Carefully thought out flat roof design
Advantages and disadvantages of a flat roof
It is clear that a well-equipped flat area at the top of the building can be used as a recreation area, a gym, or an original living room - its purpose depends entirely on the imagination and interests of the owners. But first of all, the roof of the house is the guarantor of the reliability, waterproofness and durability of the entire building. Therefore, a roof without slopes, like everything new, raises many questions, the main one among them: what is good about such a design and what may be wrong with it.
Arguments for horizontal roofing
- The flat roof attracts with its simplicity and time of installation. The roofing layers are laid on concrete slabs supported on Wall panels. There is no need to create a sheathing, use timber, boards, or other lumber; the surface is installed in one plane, without scaffolding or insurance. This saves time, finances, and resources.
- The horizontal plane design is reliable, durable, and does not require annual maintenance. Subject to technology and consistency construction work, proper arrangement of drainage of melt and rainwater, a long service life is guaranteed.
- High thermal insulation capacity of all roofing options.
A well-made roof allows you to even build a lawn on it.
- Saving materials, working time, and money costs by reducing area.
- Ease of installation and service various equipment (air conditioners, ventilation, antennas, solar panels);
- Attractive design of the facade of the house with a flat roof, clarity and completeness of lines.
- The ability to use the additionally created area at your own discretion - recreation, sports, hobbies, entertainment.
In general, the design of a house with a flat roof fits well into the surrounding nature, and a practical approach to the additional space created on the roof improves the quality of living and leisure activities.
Cons of a flat roof
The main and significant disadvantage horizontal design there is a danger of leakage. The snow that has accumulated over the winter melts and seeps through the smallest cracks, gradually expanding them, moistening the walls of the house. This common occurrence for roofs installed incorrectly. This drawback will not appear if all the work was carried out using technology, but whether this will be possible will not be known immediately.
The second most important disadvantage of a flat roof is the guaranteed accumulation of snow on it, which will have to be cleaned manually if you plan to go “out into the open sky” in winter.
Video description
What you should think about before creating a flat roof - in the video:
As a result, you can only trust the construction of a house with a flat roof to a developer who provides a guarantee for the work performed, plus, you must be prepared for snow removal work.
Main types of flat roofs
The unusual configuration of a flat roof is not only functional and beautiful, but also diverse. Without going into details, initially they are conditionally divided into two large groups - exploited and non-exploited. Each of them, in turn, is structurally performed using traditional (classical) or inversion technologies.
Separation by method of use
Exploited. They are used by the owners of the house as additional space in the house. To do this, it is important that the surface is strong, even and smooth. A slight slope of up to 5°, necessary for water drainage, does not interfere with free movement and is practically not felt. In most cases, a house with a serviceable roof is preferable due to its additional features.
Part of the flat roof can be transparent
Unexploited. Structurally simpler, since there is no need for a rigid base for waterproofing and rigid insulation. To maintain the roof, ladders and walkways are placed on it so as not to create an uneven load. This type of flat roof is cheaper to construct, but because of this, the estimated service life is shorter than a more complex flat roof in use.
Design differences
Any flat roof is a kind of “pie” in which hydro-, thermal- and vapor barriers alternate. In some versions, layers are also added to increase the overall strength of the coating.
Classic (traditional) flat roofing is also known as “soft”. Its peculiarity is the location of the waterproofing layer, which is placed outside. The softness of this coating is due to the bitumen-containing component of the waterproofing.
The disadvantage of this solution is that the top layer is constantly exposed to the sun's UV rays and temperature changes.
Their influence is especially destructive with the onset of frost, when at night the temperature may already be below zero, but during the day the air still warms up well. As a result, waterproofing deteriorates over time and moisture from rain and melting snow gets onto concrete base and through the cracks in the joints of the slabs into the building.
Pie classic flat roof
The roof is inverted or lightweight, designed taking into account sad experience use of classical. It has a significantly longer service life due to the inversion (turning over) of the arrangement of the “pie” layers, which eliminates the rapid failure of the waterproofing coating. Here, the concrete base is initially waterproofed, then there is a layer of durable hydrophobic (not wetted by water) insulation, on which there is already a “working” coating on which you can walk. Gravel, crushed stone or paving stones are often used as the latter. The quality of the inversion roof insulation allows you to even install a grass lawn on it or lay paving slabs.
Inversion roof pie
The beginning of everything is a project
Having decided to build a house with a flat roof, first of all you need to decide on the purpose of the roof - whether you need it to be used or not. There will be a serious difference in cost between them, because the first option provides for a reinforced foundation and load-bearing walls taking into account the weight of reinforced concrete floors (especially for two-story house).
The main purpose of drawing up a project is precisely to plan all the loads that the building will experience in order to determine the amount of materials that will be used for its construction. In addition, design helps to draw up a clear and understandable plan for the proposed work. Specialized programs are used to draw up the project, so it is strongly not recommended to take on this work yourself without having the necessary skills.
Moreover, you should not rely on your own strength if you want to get a house with a complex shape.
The main design stages are as follows:
- Drawing up a general sketch of the building. When the developer knows the linear parameters of the object being built and what materials it is planned to be built from, designers can already calculate the weight of the building, and therefore calculate the load on the foundation. In addition, the known shape of the structure makes it possible to calculate wind and snow loads, which are added to the weight of the house.
- Calculation of load-bearing structures. Here the number of beams to create the sheathing, their cross-section and length are calculated.
- Creation of a plan diagram. On it, except for the main walls, everything is drawn additional elements future design and their location is indicated.
Video description
Review of the project of a house with a flat roof from the architect on video:
Houses with a flat roof can be designed in almost any style, but the most functional and appropriate design is the high-tech style. This could be a small cubic house designed for a married couple or a large modern cottage with terraces on the ground and on the roof.
In addition to the adapted architectural and construction project, it is advisable to order a working plan, taking into account the characteristics of the house, in relation to the construction volumes. Thus, the total cost of the future home is determined.
The roof plan indicates the slopes and location of additional elements
What the plan should consider
Despite its apparent simplicity, the flat roof consists of quite large quantity various elements and each of them has certain nuances regarding selection and installation.
- Junction nodes. These are all the intersections of horizontal and vertical planes - outer sides, chimney walls, ventilation outlets, etc. The design of the junction units must ensure complete tightness of the connection, therefore it is carried out strictly according to the technology prescribed for the materials used.
Sealing of junction points
- Cornice. It is needed to protect the walls and blind areas of the building from water leakage from the roof, and simply gives the building an architecturally finished look. Depending on the climatic features region, the width of the cornice can be 0.5-1 meter.
The eaves extend to the required distance
- Drainage funnels. They are installed to remove water that collects from the entire surface of the roof in its lowest areas. The approximate number of funnels is one for every 0.75 m² of roof surface area.
Funnels for collecting water
- Aerators and weather vanes. The purpose of these elements is to remove water vapor that forms inside the coating cake.
Wind vane on a flat roof
- Lightning rod. It is made in the form of a horizontal mesh or vertical lightning rods.
Horizontal and vertical lightning rod on a flat roof
- Drainage Regulates the flow of water from the roof. It can be external or internal - the first option is cheaper and easier to operate.
The best way to drain water is through a drainage system.
We must always remember that the coordinated interaction of all components is ensured solely by the use of suitable materials and strict adherence to construction technology.
Examples of projects
When choosing a project for a future house, it is useful to pay attention not only to its architecture and dimensions, but also to the nature of the roof, the material of the floors, the structure of the roof and the possibility of using it as an addition to the total area of the house.
Video description
Some examples of projects in the video:
Two-story house in Hi-Tech style
High-tech modern house project with a flat roof warm walls from aerated concrete and ceramic blocks. Two-story, medium size (up to 150 m²), designed for arranging a used flat roof.
The stepped configuration made it possible to divide the upper space, where one part of the roof is used to house process equipment.
The design of the facade is interesting, combining smooth walls and textured finishes.
Project appearance
Layout of rooms on the first and second floor
Cottage
A small family with an average income can comfortably accommodate in a modern one-story compact house, the roof of which serves as an addition to the total area. Panoramic windows, big kitchen, the orientation of living quarters to the south, southwest maintains the warmth and comfort of the house.
The slight slope of the roof ensures the drainage of rain and melt water and does not interfere with safe movement on the roof. The estimated area of 86 m² is increased due to the exploitable roof. Monolithic flooring and PVC roof membrane guarantee a long service life of the house. The flat roof emphasizes the volume of the room and gives the entire structure a modern look.
Photo of the project modern house with flat roof
Room layout
Home for big family corresponds to ideas about modern construction. Good thermal and waterproofing of the roof allows you to create additional places for relaxation or training. Walls made of aerated concrete and monolithic floors keep rooms warm.
Despite the large area of the building (more than 300 m²), thanks to the flat roof it looks light and neat
On our website you can get acquainted with the most popular projects two-story houses from construction companies, presented at the exhibition of Low-Rise Country houses.
Cubic house
A square house with a flat roof in the cubist style for a family with two children looks stylish due to the absence of a high hip roof.
Neat, voluminous, with corner glazing two-storey house stands firmly on the site, attracting attention. The house is interesting from all sides, while the roof serves as its continuation, emphasizing the cubic architectural style. It is proposed to build such a house from sandwich panels, which provide sufficient thermal insulation and structural strength.
Cubic two-story house
Wooden two-story house
Not everyone prefers to use exclusively modern materials during construction, preferring time-tested classics. A wooden house with a flat roof is not easy correct solution From the point of view of environmental friendliness of the building, it is also simply a very beautiful design.
Extraordinarily beautiful wooden house modern layout
Any housewife will be happy with such a kitchen.
As a result, when should you choose a house with a flat roof?
All projects of houses with a flat roof are examples of beauty, conciseness and efficient use of space in modern buildings. If these aspects are primarily important, then such houses will be the right choice. The main thing during their construction is to choose a developer who will strictly adhere to the technology prescribed by the project.
Swimming pools and tennis courts, playgrounds and solariums, gardens and walking alleys, but only on the roof! Houses with an exploitable roof have such opportunities: in modern suburban construction they actively compete with traditional houses and offer additional areas for operation.
The portal site presents a selection of the most popular projects of houses with a flat roof. Their expressive, laconic architecture and the ability to expand functionality by open area on the roof will certainly resonate with owners of cramped areas and adherents of modern European design.
Project of a three-story house ""
Area 473 sq.m.
Roof type flat
Dimensions 19.8*18.7 m
Garage 2 cars
Number of bedrooms: 6
Number of bathrooms: 7
The serviceable roof of the Vesconti project is suitable for leisure of all generations. Children will be happy to organize a play area here, young people will set up a ping-pong table or organize a party, and the older generation will set up upholstered furniture for an outdoor recreation area.
Area 678 sq.m.
Roof type flat
Dimensions 26*25 m
Garage 2 cars
Number of bedrooms: 3
Number of bathrooms: 5
Project of a modern two-story villa with wood trim in a horizontal layout, open terraces and a built-in garage for two cars.
At the ground floor level, the left side of the villa is occupied by a garage with technical rooms, and the right side is occupied by the combined space of the living room and kitchen-dining room. The living room is adjacent to the staircase and distribution halls.
Three bedrooms, each with its own dressing room and bathroom, are located on the second floor. The office is also located here. Each room on the second floor has a corner panoramic window and access to an open terrace.
The villa is designed for permanent residence families of 4-5 people.
Area 468 sq.m.
Roof type flat
Garage 2 cars
Number of bedrooms: 3
Number of bathrooms: 4
Modern villa project with brick finishing, cantilevered second floor and built-in garage.
L-shaped in plan, the villa is designed to accommodate a family of 3-5 people and has a simple and convenient layout. At the ground floor level, one wing of the house is occupied by a garage for two cars and technical rooms. The other has a combined kitchen-dining room and living room with access to the terrace.
On the second floor there is an office and three bedrooms, each with its own dressing room and bathroom. The parent's bedroom with an obliquely cut loggia “hangs” in a cantilever above the living room. On the roof of the garage there is an open terrace with a solarium and a barbecue area.
Area 450 sq.m.
Roof type flat
Dimensions 23.2*15.4 m
Garage 2 cars
Number of bedrooms: 6
Number of bathrooms: 6
Norden belongs to eco-urbanism, is characterized by minimalism in decor, functionality and efficiency planning solutions. The project is sold together with a design project for all premises, including layout options for the usable roof, which occupies more than 160 sq.m. and is divided into three independent functional zones.
The project is very spacious and ideal for a large family6. There are not only 4 isolated bedrooms for the owners of the house, but also 2 rooms for staff. Everything is designed here Technical buildings- boiler room and garage for 2 cars. A spacious terrace on the first floor and a balcony with a garden on the second will allow you to save directly on the area of the purchased land plot, organizing quality outdoor recreation within the boundaries of the cottage itself.
Project of a two-story house " »
Area 486 sq.m.
Roof type flat
Garage 2 cars
Number of bedrooms: 3
Number of bathrooms: 4
Project of a two-story villa with corner panoramic windows, finishing natural stone and a built-in garage for two cars. The villa is designed for permanent residence of a family of 4-5 people.
At the ground floor level the house is divided into two parts. The right one is occupied by a garage and technical premises, the left one is a cross-shaped combined space of a hall with an internal main staircase, a living room, a fireplace room and a kitchen-dining room. The dining room has its own exit to the garden.
On the second floor there are four bedrooms united by a spacious hall, each with access to its own balcony. The bedrooms are interconnected with separate dressing rooms and bathrooms with natural light.
Area 573 sq.m.
Roof type flat
Garage 2 cars
Number of bedrooms: 4
Number of bathrooms: 5
Project of a two-story house with continuous glazing, open terraces and attached garage for two cars for a family of 4-5 people.
A one-story garage with a usable roof is attached to the main two-story volume of this house.
The presentation group of premises is located on the ground floor and opens onto a terrace running along the main volume of the building. This is a spacious hall with an internal main staircase, a living room with a double-sided fireplace and a kitchen-dining room. On the ground floor there is a guest or maid's room with a separate entrance.
Three bedrooms and an office, located on the second floor, are united by a beautifully lit hall and have access to balconies and a terrace located on the roof of the garage. The children's bedrooms are interconnected with separate bathrooms, the parents' bedroom has a dressing room and a bathroom with natural light.
Area 123 sq.m.
Roof type flat
Dimensions 16.14*12.94 m
Number of bedrooms: 3
Number of bathrooms: 2
Project of a one-story house with wood trim and beveled concrete walls, enclosing the terrace next to a group of bedrooms. The house is designed for construction on relief, has an outdoor pool and is designed to accommodate a family of 3-5 people.
The planning solution for this house involves dividing it into two parts - presentation and private. The presentation room is a spacious living room with a fireplace area and a kitchen-dining room. The kitchen has a work island and an adjacent food pantry. The presentation part of the house opens onto a terrace with a swimming pool and an outdoor solarium.
The private part consists of two children's bedrooms and a parent's bedroom, each with access to a terrace. At the same time, the parent bedroom has two opposite exits - to the side terrace, enclosed by concrete walls, and to the main one, with a swimming pool.
Project of a three-story house ""
Area 357 sq.m.
Roof type flat
Dimensions 14.7*12.9 m
Number of bedrooms: 4
Number of bathrooms: 3
The minimalism of "Alicante" will appeal to many buyers. Simple, but at the same time harmonious, this project will fit into a site even with modest dimensions. And the ergonomics of the interior makes the house functional and comfortable for a family of 5-6 people.
Area 214 sq.m.
Roof type flat
Dimensions 11.66*14.66 m
Garage 1 car space
Number of bedrooms: 5
Number of bathrooms: 3
Project of a modern two-story house with a built-in garage, decorative shutters on the facade and colored exterior lighting.
The breading solution of the house assumes that a family of 5-7 people will live in it permanently. On the ground floor level there is a spacious living room with corner fireplace and exit to the terrace. Next to it is an open kitchen-dining room with a work island, dining table and a large food pantry. At the ground floor level there is a bedroom for older family members, which can also be used as a guest room.
Three children's rooms - each with its own mini-office, but with a common dressing room and bathroom, are located on the second floor. There is also a parent's bedroom, designed as a single block with a bathroom and dressing room and having access to a balcony.
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Most often, when designing private houses, pitched roofs are used, but cottages with a flat roof, as in the photo, are much less common. In recent years after the emergence latest technologies And modern materials for covering flat roofs it is possible to create effective waterproofing, despite their unusual shape.
The presence of such a roof makes appearance a private house is exclusive and original, as it stands out against the background of buildings with hipped or pitched roofs.
Projects of cottages with a flat roof have their own characteristics, and their construction is associated with some nuances, since the roofs on them can be:
Advantages and disadvantages of a flat roof
Flat roof provides the property owner with a number of advantages, including:
The disadvantages of the structural solution of flat roofs include:
- carrying out installation with strict adherence to the technology of their waterproofing and. The slightest violation of the rules as a result of negligence or negligence results in the roof leaking if precipitation accumulates on it. Extraordinary roofing repairs will cost a considerable amount, and sometimes it is necessary to carry out a complete reconstruction of the cottage roof;
- availability in winter period on a flat surface, a large amount of snow requires (if the roof is planned to be used) regular snow removal, which can only be done manually;
- During the melting of snow, a significant load is placed on the waterproofing layer
Features of flat roofs
When developing a project for a cottage with a flat roof, regardless of the number of floors in it, the following features must be taken into account:
Creating a flat lightweight roof
If they plan to build a cottage with a flat roof with a lightweight roof, they do not plan to use it.
The procedure for constructing such a structure is as follows:
As a result of the work performed, a flat roof is obtained, which is of the lightweight type. It performs the functions assigned to it completely, but it is not able to withstand even a slight load. If you want to create a small place for rest on a flat roof, you need to build the roof using a completely different technology.
Construction of a house with a flat roof, more details in the video:
Construction of an exploitable flat roof
When designing cottages with a flat roof and a hard surface, it is assumed that the created roof will not sag under the weight of the load (read: ""). There are several ways to construct a serviceable pavement.
One of the most simple options is styling concrete slabs as a cover. For this purpose, the supporting structures must have a significant margin of safety; in addition, installation is carried out using special construction equipment. A roof made of concrete slabs must be insulated, but such work can only be done from inside the room.
Another method is the construction of a roofing floor based on metal support beams - T-bars or I-beams and channels. A boardwalk made of lumber with a minimum thickness of 22 millimeters is laid on top, and a layer of expanded clay of at least 150 millimeters is poured on top of it. The hard covering is provided by a concrete screed.
The most in a modern way For solid construction, the use of large-sized ceramic building blocks is considered. They are laid on support beams, and they provide the roof, along with mechanical strength, with fairly good sound insulation and thermal insulation characteristics. Among the advantages of such ceramic roofing blocks, one cannot fail to mention their excellent resistance to moisture. Before making a screed for such a roof, backfilling with expanded clay is not required. The disadvantages of ceramic blocks include their high cost.
Cottages are built with a flat roof of a solid type with the installation of roofing membranes (optional). They provide additional waterproofing and improve performance characteristics flat roof.
For many, flat roofing is associated with urban multi-storey buildings, faceless and monotonous. But we are ready to surprise you! A flat roof in a private house will be a pleasant discovery for you if there is not much snow in your area, but the winds are quite strong. The fact is that in winter all snow accumulations from such a roof will simply be blown away. And the main thing is that not a single strong hurricane can tear off a roof that simply does not exist! And a whole ocean of possibilities opens up before you, which you can now build above your head: a cafe, a dance floor, a mini-garden and even a whole greenhouse!
The main thing is to know about all the intricacies of constructing houses with a flat roof, and everything will work out. And now we will reveal all the secrets.
- Such a roof is much smaller in area than the most gently sloping roof. And this means savings on materials.
- Such a roof is built much faster than a gable roof, and even more so a hip roof.
- Comfort and safety of all rafter work. You still have to manage to fall from such a roof!
- Convenient subsequent repairs and replacement of roofing.
- Unlike two pitched roof, dismantling the old flat covering is usually not necessary - this is additional waterproofing and protection. The new pie is made directly from the old one, which saves a lot of time and effort.
- The ability to use the roof as an additional useful area where you can plant a flower garden, make an open terrace and even build a greenhouse.
- The ability to install transparent roof elements (with careful waterproofing), and thus create a view of the night sky.
- Opportunity to build a house with a laconic architectural form. Minimalism is at the height of fashion!
And now – about the pros and cons:
- Such a roof generously accumulates snow. After all, he now has nowhere to slide, and the snow itself often becomes the cause of leaks.
- On especially generous days, the snow will have to be removed mechanically, which often damages the roofing.
- The structure of the roof becomes more complicated: now we need gutters, which also become clogged.
- The difference is that water drains from a pitched roof quite quickly (and sometimes it does get into the under-roof space). But on a flat one it actually stands!
Monitoring the moisture content of the insulation and the general condition of the roof should be regular. - But, despite the fact that for its arrangement building materials you need much less than for a pitched roof; a flat roof is much more complex in terms of installation. Let's just say that there are many more different subtleties and nuances that are important to know about.
That is why many have fair doubts about the reliability of such a roof. But the European and overseas experience of private residential buildings with a flat roof is successful, and therefore you can safely get down to business.
Just consider these points:
- There is much more snow in Russia than in warmer European countries.
- The only thing worse than snow is the large difference between summer and winter temperatures, which not all foreign roofing materials are designed for.
And here technology decides everything!
What is a flat roof?
So, what acts as the load-bearing base of a flat roof:
- Reinforced concrete slab.
- Roofing sandwich panels.
- Reinforced steel corrugated sheet.
And thanks to the fact that they learned to make a flat roof “breathable”, i.e. with internal ventilation, it has now become possible to use completely non-breathable waterproofing - roofing felt similar to it.
Any roof that we call flat actually still has a slight slope: to one side or specifically towards the drainpipe.
Here is the simplest example of a flat roof for a private home:
Types of flat roofing: non-exploitable and inverted
Of course, unused roofs are cheaper. And the exploited ones, which are correctly called “inversion”, include additional materials.
A separate type of flat roof of a residential building is exploitable. Those. the one on which people will walk and what objects will stand. This is the same garden, or sports ground, or summer cafe. All this creates considerable loads on the roof, and therefore its design is already different from that which is intended only to protect the house from precipitation.
So, the main difference in the design of traditional and inversion roofing is that in the first, the thermal insulation layer is located under the waterproofing, which is quite logical, and in the second, it is above it. But in the second option, the waterproofing is more protected from ultraviolet rays and temperature changes. This design is more durable and functional: you can safely lay out a lawn or lay paving slabs on it.
And now in more detail.
Unused roof: standard pie
But on unused roof A person can also get up occasionally - for the same repairs, for example.
Those. in a traditional flat roof, the top layer is waterproofing, and it is this that is exposed to all mechanical and temperature loads.
A separate type of it is a roof with a pressure layer, which is designed so that a person can walk on it from time to time:
Inversion roofing: reverse pie
The standard slope of an inversion roof is 5-7%. The inversion method assumes that the thermal insulation layer is already placed on top of the waterproofing, which now also serves as a vapor barrier.
Moreover, the pie of inversion flat roofs can be very different. It all depends on what you are going to arrange on the roof: a terrace, a mini-pool (and this is not uncommon) or a garden. But the base will still be common: a monolithic screed is made, which levels the entire surface, then waterproofing is laid and the whole thing is covered with insulation. And on top is a cement-sand mixture or rubber coating.
Note that active use of the roof means frequent damage to the insulating layer, which is why moisture makes its way to the insulation and freezes in winter. Over time, the entire roofing pie deteriorates, and therefore without ventilation system A flat roof is indispensable.
Cement-sand screed is capable of even better distributing the pressure layer on the heat insulator, but it must be additionally reinforced with a mesh to prevent cracking.
Subtleties of flat roof insulation
A layer of thermal insulation for a flat roof is mandatory. For comparison: gable roof insulated only when equipment is installed underneath residential attic, and in all other cases the maximum is laid mineral wool on the attic floor. But for a flat roof, insulation is always necessary.
The fact is that without a heat-insulating layer in a flat roof, condensation will constantly appear on the ceiling in the house (such a roof will turn out to be the cold part on which water vapor will rush). And this is bad not only because repairs will have to be made, but also because the entire structure deteriorates.
You can insulate a flat roof both from the outside and from the inside - the difference is small. What is more important is how many layers of insulation a particular roof needs – one or two.
Thermal insulation materials must be attached to the base of the roof mechanically, both screws or dowels, and glue. Sometimes the fastening is not used at all if the heat insulator is located from the outside and there is pressure on it paving slabs or pebbles.
Why two layers? The fact is that the first layer of thermal insulation on a flat roof acts as insulation; it is from 70 to 200 mm thick. And the second, from 40 to 50 mm, is designed to distribute all the loads. And it is important to calculate the thickness of both layers accurately, based on the climatic characteristics of the area and the future use of the roof itself.
With double-layer insulation, all joints should be spaced apart, in a checkerboard pattern, so as not to overlap each other. Moreover, in the places where the slabs adjoin the walls and parapet, it is additionally necessary to make heat-insulating sides. A cement-sand screed can even better distribute the pressure layer on the heat insulator, but it must be additionally reinforced with a mesh to prevent cracking.
Proper drainage system
But this is already a difficult task. Flat roofs are just bad because they are completely open to rain. But everything can be solved! The main thing is to properly organize the drainage, and for convenience, we have explained this issue for you in the following schematic illustrations:
Internal ventilation device
Another important point when installing flat roofs - ventilation. The fact is that if moisture accidentally gets into the insulation, it no longer evaporates - it only accumulates. As a result, the heat-insulating material rots and the waterproofing swells. And there are many reasons for leaks: damaged waterproofing, mechanical damage to the top layer of the roof, cracks and damage from frozen water.
A wet thermal insulator is also bad because it causes bubbles and cracks to appear on a flat roof in the summer heat - all due to the active evaporation of water. As a result, the roof covering also collapses. And if moisture gets under the old screed over time, then the entire roof begins to peel off. This is why a flat roof must “breathe”.
For this purpose, so-called aerators are used. They look like simple plastic or metal pipes, covered with umbrella caps. They should be located evenly over the entire roof area, preferably at its highest points. The essence of this mechanism is that different pressures are created inside the roof and the air begins to create currents, simultaneously taking with it all the excess moisture vapor.
In practice it looks like this:
In addition, in any living space, water vapor rises up to the ceiling. Moreover, they often successfully overcome this barrier (the water molecule is very small) and end up in the insulation, which is bad for it. This is why vapor barrier is required. And not the kind that is usually used for attic insulation, but a dense one, made of high-quality polypropylene or polyethylene. The bitumen membrane is even more reliable.
Choosing a suitable roofing covering
So, what is used as a coating for such roofs?
Option #1 – bitumen and polymer-bitumen materials
Such roofs are the least expensive for owners of private houses. We are mainly talking about roofing felt and euroroofing felt. These are rolled roofing sheets, the base of which is synthetic fabric, and the sides are bitumen. As an elastic and frost-resistant material, bitumen serves as excellent protection and waterproofing.
Moreover, laying bitumen roofing on a flat roof is absolutely simple, you only need gas-burner. The rolls are easily fused together.
But such a roof has significant drawback– fragility. And another thing is that roofing felt does not breathe at all, i.e. It is vapor-tight, and therefore it is necessary to arrange ventilation for such a roof, unless you want the insulation to rot within a year:
Option #2 – liquid rubber
Such roofs have the great advantage that they do not contain any seams. As we have already said, the disadvantage of a flat roof is, first of all, that snow accumulates on it, which then causes leaks.
But there are some subtleties here. So, you only need to take two-component liquid rubber for a flat roof, preferably the highest quality one. And it is extremely important to apply this material correctly to a flat roof: evenly, avoiding unnecessary layers and saving in certain places. So, where the paint was applied unevenly, problems should be expected within 8-10 years.
Option #3 – PVC, TPO and EPDM membranes
Roofing membranes are valuable as a covering for flat roofs because they allow steam to escape. After all, no matter what kind of vapor barrier is used, moisture still, at least a little, gets into the insulation, not only from below, but also from above - after heavy rains, for example.
There are three types of membranes for installing such a roof: TPO, PVC and EPDM. The most popular is PVC membrane, which is also the most flammable. An EPDM membrane is more durable and affordable, but if mechanical damage occurs in it, nothing can be done to fix it, whereas a PVC membrane can only be melted with a hairdryer. In addition, the joints of the EPDM membrane must be glued with a special tape, which is much less reliable than soldering PVC sheets.
But the cheapest membrane in its sector is PVC. But it has such significant disadvantages as low resistance to ultraviolet rays and fear of contact with bitumen, various oils and even polystyrene foam, otherwise the service life will be significantly reduced.
Gluing EPDM membranes requires professional skills. TPO membrane, like PVC, is also welded with hot air. The best is not afraid of ultraviolet radiation, is more chemically resistant and can be laid directly on polystyrene foam or an old bitumen roof without geotextiles. But its service life is shorter than that of EPDM, so for installing a flat roof on a residential private house, we recommend using a PVC membrane.
So, a flat roof device with a PVC membrane is traditionally made like this:
- Step 1. We arrange a monolithic floor slab.
- Step 2. Place a tear-resistant vapor barrier film.
- Step 3. We make a bend from insulation or screed.
- Step 4. Place insulation. In private construction this is usually 35 density foam, and on top is 50 mm XPS, which is even stronger.
- Step 5. Now geotextiles, 300-500 g per square meter.
- Step 6. Let's move on to waterproofing - this is a PVC membrane. The insulation density is enough to allow walking on such a roof. But, if you plan to make an open terrace on the roof, then you need to continue the pie further.
- Step 7. Lay the geotextile again - now directly on the membrane.
We lay rubber tiles or reinforced screed 5-7 cm, on which we already lay paving slabs. To make a screed, you need ballast.
And such roofs are made of rubber, polymers or even foil. Unlike bitumen, they are durable, fire-resistant and adhere firmly to the base. A slight slope is achieved using expanded clay concrete or concrete screed.
How to achieve 100% waterproofing?
The main task when installing a flat roof is to make all joints and junctions as airtight as possible. After all, such a roof is most affected by moisture, hail, temperature changes and wind-blown debris. Therefore, the sealants used to seal such joints must be of high quality and resistant to any influences. This is also a kind of expense that has to be incurred.
For the same purpose of waterproofing, it is recommended to make the slope of a flat roof at least 2%. Few? In fact, this is quite enough so that all atmospheric moisture does not linger on the surface, but flows down into funnels and pipes, and from them into the septic tank, soil or sewerage system. Therefore, even at the design stage, you need to carefully think through the future drainage system.
Moreover, the drainage system itself is made both internal and external. Thus, internal drainage is made up of fittings - funnels located throughout the roof, which receive the flowing water and direct it into pipes that go through the buildings, but are isolated from the living quarters. The only disadvantage of such a system is that the pipes become clogged with small debris and leaves, for which it is advisable to equip them with special filters and periodically clean them.
External drainage systems are already attached to the outer walls of the building. These are, of course, easier to clean when they become clogged, but in cold weather they often freeze over. For this reason, it is customary to additionally supply them with electrical heating in the form of cables.
As for the material for the internal and external drainage system of a flat roof, PVC or metal is quite suitable. Both options have their pros and cons. Thus, polyvinyl chloride does not corrode, but is more brittle than metal.
To prevent gutters from freezing in winter, equip them with roofing thermal cables.
Green area on the roof: fashionable and environmentally friendly
Greenery and recreation areas are often lacking not only for residents of the “concrete jungle”, but even for owners of private houses. The whole point is that the same beautiful garden furniture It’s not always possible to leave it in the yard of the house, and beautiful rare flowers in the garden flower bed are often trampled by pets. Therefore, it is not surprising that the green area on the roof has become fashionable among cottage owners. Especially if the access to it comes directly from the bedroom and no one else can disturb your morning peace with a cup of coffee.
There has also become a fashion for some cafes to make the roof flat and put a small greenhouse on it. All the greens go straight to the table! And it’s profitable, because it’s not so easy to bring fresh dill or onions to the kitchen, and it’s economically profitable - there’s somewhere to send kitchen waste. And it is difficult to understand who borrowed this idea from whom: enterprising residents of private houses with a flat roof, or the best minds in public catering. But the fact that such an arrangement of closed ground is beneficial is a fact: rodents will not dig under the beds, insects and pests will not reach (as well as pests in the form of neighbors), and the fact that it is always a little hotter on the roof is only a plus for the same tomatoes. But the main thing is to correctly calculate the loads on such a roof during construction!
And the roofing pie is often standard: waterproofing for the ceiling, thermal insulation, geotextiles, drainage and geotextiles again. And on top you can use both soil and beds:
Or in this version for more powerful floors:
A flat roof is a huge scope for any imagination. Designers and architects love to bring to life a variety of projects for her: a garden, a greenhouse, a jogging track, a mini-beach with sun loungers, and much more. Some craftsmen even manage to make a parking lot on it!
