How to make a mansard roof of a house from a bar. Beautiful and comfortable attic: device and calculation

The attic is the room in your house that can carry the most diverse functional load: from a workshop and an office, to a bedroom and a living room. The arrangement of the attic will cost you much less than a full-fledged second floor. And the technology of its construction is more accessible for execution.
In this article, we will consider the types of attics, as well as the stages of building an attic with your own hands.

The attic is a room bounded from below by an interfloor overlap, and from above and on the sides by roof slopes. Depending on the shape of the attic slopes, there can be:

single-level symmetrical with a gable roof (a, b);
single-level symmetrical with a sloping roof (c);
single-level asymmetric (d);
two-level asymmetric (d).

Roof truss structures

If it is not there, or the distance of the wall from the edge of the attic is more than 7 m, hanging-type rafters are mounted. They are made up of the upper part of the roof slope, and below are limited by the ceiling beams of the attic.
Installation of the truss system is the first stage in the construction of the attic. Therefore, before starting its installation, it is necessary to calculate and take into account all the subtleties of this construction. For example, the possibility of arranging an attic floor instead of an existing attic space will depend on the quality of the underlying surface, on the type of foundation and its bearing capacity, as well as on the condition of the entire building as a whole.

However, first you need to familiarize yourself with the terminology presented on the construction drawings.

Stages of construction of the truss frame

First, the upper bar is laid, which can be a section of 0.1x0.1 m, and preferably 0.15x0.15 m. It is attached to the racks with special nails, iron staples or self-tapping screws. This bar is a rafter frame.

We make installation of Mauerlat. It is this element that is the "foundation" of the entire roof. It prevents the roof from tipping over in strong gusty winds, and also shifts the load from the attic to the load-bearing walls of the house. For mounting the power plate, use: boards (thickness not less than 5 cm) and bars (with a minimum section of 10x15 cm). The bars are laid out along the perimeter of the entire roof and attached to the wall with long self-tapping screws or metal brackets (or better, both at the same time). Another method of attaching the Mauerlat to the wall will not be superfluous - using a thick wire, which is pre-mounted in the top row of the brickwork of the wall. Remember that the stronger you tie the Mauerlat and the wall, the stronger the entire attic structure will be. And one more thing: under the Mauerlat bars, it is necessary to lay a layer of a waterproofing agent, and treat the boards or bars themselves with an antiseptic and waterproofing impregnation.
, which are most often purchased ready-made (although you can make them yourself if you wish). Before mounting these structural elements, it is necessary to put marks on the Mauerlat that will indicate the place where the legs are attached (the accepted distance between the legs is 15 cm). Labeling will simplify and speed up the implementation of this step.
We lay the edge rafters to the pediment. Particular attention should be paid to the fact that the edge of the front and the top of the rafters should be in one line. In addition, pay attention to the quality of the board used under the rafters: it should be without any special defects (normally no more than 3 flaws per 1 m), thickness - about 4 cm, width - about 15 cm. After the edge rafters are installed, they are connected by a level rope, along which all other rafter legs are mounted.
It's time to bring all the straps together. This is done along the top point of all rafters using a run. Then the ridge beam is installed, which, in principle, is not an obligatory element of the frame (it is erected when the roof is longer than 7 m).
Do not forget that at the stage of erecting the truss structure, you need to lay window frames under the roof windows.
If the roof is lower than 7 m, then extensions are mounted in the upper part of the rafters, which perform a dual function: they serve as ceiling beams for the future attic, strengthen the frame of the attic roof.

The rafter system is ready. It remains only to make the crate, fix the hydro-barrier material, lay a layer of insulation material, as well as roofing. Mansard roof is ready. We proceed to the internal work, which we will discuss below.

The importance of insulating mansard roofs is undeniable, because. the walls of the attic room are united with the mansard roof, or as close as possible to it. Because of this, the attic room freezes faster in winter, and heats up significantly in summer.

Mineral wool is laid in the space between the rafters. In this regard, the base sheets of insulation are cut to the size of the gaps between the rafters. Sheets of mineral wool are laid on a pre-laid layer of vapor barrier, and a layer of hydro vapor barrier is attached on top of the sheets. In this multilayer structure, air gaps are formed, located between the layers of a vapor barrier-mineral wool and mineral wool - a hydro vapor barrier. These air channels will subsequently contribute to the ventilation of the entire structure, and therefore they must be brought open in the ridge area. This will improve the quality of the insulation.

When insulating the attic, remember that the microclimate of the attic room and the comfort of your stay there will depend on the quality of insulation and the availability of ventilation.

Creating an attic - a popular type of room - with your own hands today is not difficult. Let's look at all the stages of construction, as well as the pros and cons of this design.

Peculiarities

Home is a place where we would like to surround ourselves with comfort, have the opportunity to relax with our families and work. Sometimes this becomes impossible due to lack of square meters. How to make housing spacious and comfortable? Construction technologies have stepped far ahead - resources have appeared that allow you to expand the occupied space with your own hands through extensions. But if there is not enough land, then the attic will be the most successful option!

Currently, this is a fashionable design for private houses. Back in the 17th century, the attic was conceived as a way to expand housing for the poor. And thanks to the French architect Mansard (fr. Mansard), the conversion of roofs into residential apartments has become very popular among the rich. From here, by the way, the name came - attic.

Many people ask the question: "Attic or additional floor?". It is worth clarifying right away that these are two different things. Before choosing one or another option, weigh all the pros and cons, the pros and cons, consider the purpose of your home (cottage or permanent residence), your marital status, and budget. It will be much more economical to build an attic than a full-fledged second floor.

In this article, we will tell you how to significantly transform the usable area with minimal investment. And with the implementation of all the necessary activities, you can handle it on your own.

Installation and arrangement of the attic, the facade of which is completely or partially formed by the surface of a sloping roof, is a vast scope for imagination and creativity. So much space shouldn't be wasted! A great studio, office or storage space for unnecessary things will come out here. But isn't it too wasteful to turn precious square meters into a warehouse?

Typically, attic spaces are provided to children who like to be placed on high levels, and besides, low beams often cause some inconvenience to adults. This floor is the last one, and the higher, the better the view, no doubt. The presence of pipes, the proximity to the roof, a remote balcony, a sloping ceiling - all this will become a stylish help for creating an architectural design.

An objective assessment of the specifics and knowledge of the constructive qualities of this type of superstructure give a chance that everything will work out as well as possible, the load-bearing walls and foundation of the house will not be harmed, and the dwelling will last a long time. Believe me, the attic is a very useful thing!

The most successful solution is a frame attic. Before you begin to develop a superstructure plan, you must make sure that the lower floor can withstand the additional load. After all, every person who encounters a building knows that the main building is placed on a supporting structure, which is calculated based on the entire mass of the building. Therefore, at the beginning of construction, it is necessary to make the necessary calculations, as well as check the foundation for cracks or any damage on it. If necessary, the base will need to be strengthened. At this stage, it is best to turn to professionals.

Based on how the roof is constructed, the appearance of the attic can be different. As a rule, the attic occupies the entire top floor, although sometimes there are options located on one side of the longitudinal axis of the building. It is not often possible to see attics that extend beyond the lower structures.

Most often, the roof is gable or broken. A more complex type of gable configuration is popular: the roof consists of two planes, as it were. But we will discuss each of them in more detail a little later. Windows, large or small, located on the ceiling let in many times more light than ordinary windows in the rooms on the lower floors.

When choosing a roofing, observe harmony so as not to disturb the combination of the shape of the attic floor and the roof.

You can also immediately insulate the room with SIP panels. As a result, you will get a lightweight construction, which consists of more than 50% of lightweight polystyrene foam, therefore, it does not create a load on walls and ceilings.

There are several design features that cannot be ignored.

take seriously the thermal insulation, which should be strengthened, because it is the roof that often “suffers” from frequent and sometimes strong temperature changes;
it is important to make waterproofing conscientiously, so that over time the insulation does not get wet;
between the thermal insulation layer and the roof, ventilation must be done properly.

The parameters of the truss structure should be determined by the further construction of thermal insulation, which is placed between the timber rafters and has a thickness of at least 20 cm. The rafters must be at least 25 by 25 cm.

The main indicators of wood that are important for the design of the system are flexural and compressive strength, the desired density and moisture content.

Wooden rafters, in turn, require treatment with antiseptics or fire and bioprotective structures and must have fire resistance limits.

Designers are advised to leave the attic space intact. Nevertheless, if it becomes necessary to separate rooms, then it is better to build partitions using drywall.

Consider also the disadvantages of this type of adjustment:

due to the sloping roof, unlike the usual floor, the size of the attic area will be smaller;
the height must be optimal, otherwise there will be problems with closing / opening the doors;
psychological factor: sometimes it seems to people that there is not enough air, every time you want to bend down, a person may feel discomfort;
regardless of the type of roofing and even the correct installation of sound insulation, sounds from rain will penetrate into the room;
it is important to think over the heating system correctly;
the stairs leading to the attic may be too steep and therefore unsafe.

Design options and materials

Using the advice of experts, carefully develop a future attic project. After that, prepare the design of the attic, as this is not just a certain number of square meters, but the individuality of the facade - the pride of the building. The appearance and interior depends on the methods of coating and materials for the roof.

There are several types of roofing.

Shed

The simplest option, which is a sloping area fixed on load-bearing walls. Advantages: ease of calculations and installation work, due to its low weight it is suitable for buildings on simplified foundations. Disadvantages: not the most attractive appearance, sensitivity to loads (snow).

gable

One of the most common options. Such a structure consists of two opposite slopes, which lie on the walls of the building that serve as a support and are connected at the top with a ridge. Material investments in a gable roof are quite small, while it looks aesthetically attractive. The gable roof device includes: rafters, lathing, inclined planes, mauerlat, horizontal ribs, ridge, valleys, overhangs.

broken line

The broken roof structure is a subspecies of the gable roof, but with a more complex configuration. Because of the shape and the presence of broken lines, this name came about. Such a roof gives the house solidity and solidity.

Four-sided or hip

One of the strongest and most resistant to strong winds and leaks during rainfall roofing systems, where two triangular slopes are installed instead of gables. Complex installation is a minus of this design: it requires accuracy in calculating the truss system and installing the frame. For this reason, designing is usually trusted to professionals.

Multi-forceps

Among all the designs, the most complex, but at the same time the most interesting is considered to be multi-forceps. It is characterized by the presence of several gables (from 3 or more). A big plus is the ability to cover several rooms with one level. But in general, this type of attic works mainly on the architectural style and design.

The attic part is divided into two types. She may be:

single-level- a fairly practical option in execution that does not require complex development and serious calculations;
two-level- This is a building that is difficult to erect, the project of which is created immediately together with the house.

Current building technologies make it possible to make different types of balconies in the attic. To select the desired design, you should consider the design features of the lower floor. And it doesn't matter if the balcony was already included in the plan, it can be done at the end of all stages of construction.

The most successful location option is from the side of the end. In this case, the balcony will resemble a loggia. It is erected together with the attic, which allows you to use part of the roof as a canopy, and the ceiling of the floor as a floor.

Another type of construction is the option when the balcony is located in the roof part. At the stage of roofing, part of the building is left uncovered so that a balcony can be equipped there.

Drawings and calculation

The main parameter when planning the attic floor is the ceiling level, the optimal height of which should be at least 2.5 m. Make a drawing before direct construction, evaluate everything and indicate accurate calculations so that everything can be built accurately. The most ideal option is a broken gable roof, but then as many bearing supports as possible should be installed for sufficient reliability, since this type of roof increases the pressure on the walls.

Do not forget to include the ventilation system in the calculations, as well as windows and furnace heating pipes, if any.

The height of the superstructure itself has no limit, but the lower ends must be at least 90 cm.

The plan should contain all the information about the shape features, geometric dimensions and slope angles of the slopes.

After the exact calculation of the mansard roof truss system is completed, all the necessary materials should be purchased and the roof should be prepared. Only after that, you can start building.

Do-it-yourself attic manufacturing steps

It is very important to choose the design and style of the interior at the initial stage, as well as decide on the materials for decoration. You should listen to the opinion of professional designers who advise using only high-quality raw materials. We will guide you step by step through all stages of construction.

Roof

So, the first stage is the development of a project for a new future roof in an old room. It does not matter whether it is single-pitched, double-pitched or broken, without a doubt the appearance of the result will directly depend on the structural properties of the roof, as well as the raw materials used. Make a diagram in different perspectives to better understand how to place the elements of the truss system. The most important thing is to accurately calculate the height of the roof ridge, because the size of the area under it depends on it.

We take the height of the ridge about 3.5 m - with the independent construction of the frame, which allows you to straighten up to your full height.

It is important to remember that in order to build a frame with your own hands, you must be aware of the existence of two types of truss systems: inclined and hanging. They differ from each other by the method of attaching nodes to the walls.

In houses where there is no load-bearing wall, the mechanism of hanging rafters will be used, which will be held only on the walls of the house and connected to each other with nails or screws using corner plates. In this case, the width of a single-span building, where this particular type of rafters is assumed, cannot exceed 6 m. If the parameters of the house are larger, for example, when the span width exceeds 9 m, then more struts have to be done.

In two-span houses, where there is only an average supporting wall, layered rafters are made. In this case, the three base points (two on the outer walls of the house and one on the inside) depend on the width of the building: more than 10 m - one support, and with a width of about 15 m, two supports will be needed. The rafters are attached to each other with the help of corner plates. The crate itself is made of slats or boards.

Steam and thermal insulation are key steps in creating an attic. A membrane-type film is laid on top of the crate, which will protect against moisture penetration, and glass wool is laid on the inside for insulation.

The next stage is the installation of the roof, interior processing and design of walls and partitions, as well as the installation of windows.

As we have already mentioned above, the most successful will be the use of metal tiles or corrugated board as a material for roofing.

floors

First, take care of sound and thermal insulation from the floor below. This task can be accomplished in several ways: backfilling of expanded clay or laying mineral wool slabs. Both methods involve protection from moisture with hydrofilms. Also pay attention to the wooden floors. Here, the insulation is performed with dressing of the seams of the insulation and beams.

Choose the flooring of your choice. It can be ceramic, parquet or laminate.

Window

Loft windows are quite a labor intensive but worthwhile process, so consider if you can do it yourself. In fact, they do not differ much from facade ones, but there is one serious difference - a special type of opening. In addition, during installation, you will have to disassemble the metal tile, while trying to maintain waterproofing. But this is not scary, because it is thanks to the windows that the room becomes much lighter and more spacious!

It is very important to know that if snow and ice are not cleared regularly, the window may be subject to temperature changes, so it is important to select models according to the climate in which you live.

Heating selection

For a comfortable stay and use of the premises, you also need to take care of heating the attic. It should not only maintain and retain heat inside, but also be safe and economical.

It is necessary to take into account all the details at the initial stages of design. We bring to your attention several methods of heating the attic floor.

Fireplace. Efficient, comfortable and completely safe way.
If your house already has a heating system on the ground floor, then you only need to install additional pipes and batteries.

Installation of an independent heating system only for the attic - the most correct solution. It is possible to install absolutely any heating boilers, while observing the necessary safety measures. But more convenient - turbocharged gas boilers that do not require a separate room. They are wall mounted and very easy to use.
"Warm floor". To create a comfortable microclimate in the room, you can install underfloor heating. This can be done both with your own hands and with the help of specialists. In any case, this is a fairly economical option.

An important point is the proper arrangement of ventilation. Only in this way will attic heating work well.

Warming and ventilation

Since the attic has the largest area of contact with the street, compared to the lower floors, its insulation should be taken very carefully. Today the market offers a variety of insulating materials. However, when solving this problem regarding full-fledged thermal insulation and vapor barrier for the house, do not forget about the main conditions, and then this will not only reduce heat loss and heating costs at home, but also protect the ceiling and walls from dampness, rot and sputum, the formation of frost on the roof . The choice of materials for the "roofing pie" must be carried out in accordance with the requirements of SNiP.

When you choose a finish in a store, focus primarily on the characteristics of your home. For example, where it is hot in summer and frosty in winter, the insulation must be resistant to external circumstances. Therefore, one of the main conditions will be thickness. The colder, the denser it should be, and, conversely, if you live in the south, where the temperature practically does not drop below zero in winter, you can choose a thinner material.

The most versatile and most budgetary - based on mineral wool, polystyrene foam is used less often. Sometimes it is possible to use a heat-insulating layer consisting of modern filling agents or materials in the form of a liquid sprayed onto the walls and solidifying into a solid form. In all these cases, the roof will come out no less stable.

With the correct assembly of the “roofing pie”, the design of which consists of metal tiles or corrugated board, lathing, waterproofing membrane, truss system, properly equipped ventilation of the under-roof space is sure to extend the life of your roof. Never play the lottery "will carry it - will not carry it", but "wind it on your mustache" the advice of experts.

To create a beautiful and cozy living space, you can use wood as a finishing material from the inside, various types of composite panels, HPL panels (or HPL in Russian - high pressure laminate). No less popular is the attic, decorated with your own hands using drywall sheets (gypsum plasterboard).

Roofing should be made of lightweight materials: corrugated board, metal tiles and similar materials that can lighten the weight of the mechanism, taking into account the load that will be transferred to an existing building.

To begin with - before altering the attic - you need to make drawings and draw up an estimate. This way you will see in advance what difficulties you will face.

It is not easy to develop a plan for a mansard roof alone: certain knowledge and skills in designing and carrying out specific calculations are important here. You can’t make mistakes: then the structure of the building will be unreliable, and besides, it can damage the overall building. Although if the idea is not too complicated, then you can do it yourself.

Everything must be included in the estimate: from the beginning of construction to the design of the premises.

Partitions

One of the simplest tasks that you can definitely handle with your own hands is the installation of interior partitions. Usually, drywall and metal profiles are used for these purposes. Everything is done quickly and at minimal cost.

The design is simple: a frame, and gypsum boards are attached to it. At the end, the lining of the partition is made. To do this, you can use lining, block house, imitation timber or even plywood with wallpaper - a matter of taste.

Finishing work

After warming the attic, you should think about finishing. Of course, it all depends on how you will use this room. The peculiar geometry provides excellent prospects for creative design solutions. Immediately, we note that the finishing process is a complex of tasks, each of which has its own function. Let's take a closer look at finishing materials.

The most popular material plastic lining. Advantages: uniqueness, budget, environmental friendliness. The installation of the board can be different: diagonally or in a circle, horizontal or vertical. Of the minuses, it is worth noting fragility and, perhaps, weak resistance to negative factors.

Not the most expensive material plywood sheet. Covering the walls with them is quite easy. It also has excellent sound and heat insulating properties; no pre-leveling of the surface is required before installation.
Finishing the attic with drywall will allow you to embody the most original design solutions: with its help you can create false ceilings, arches and even columns. At the same time, this material easily absorbs moisture, which is its negative side. But if you choose a special type that is resistant to moisture, then this finish will last you a very long time.

So, let's sum up and summarize the above.

To design a beautiful and high-quality attic you will need:

careful design of the future extension;
strengthening load-bearing walls and foundations;
roof removal;
erection of the frame (it will be easy enough for you to assemble it with your own hands);
roof insulation, waterproofing;
window installation;
interior decoration and insulation.

With excessive savings, as practice shows, the house can eventually turn out to be of poor quality and unattractive. Therefore, choose materials wisely, take into account the recommendations of experts, consult relatives and friends, as well as those who already have similar experience.

If you want to maximize the usable area of the house without spending fabulous money, you should definitely consider projects with an attic. The experience of developers suggests that this is the best way to plan economy class housing, because one square meter of living space in it costs several times cheaper than in two-story buildings. There is a misconception that the attic is suitable only for seasonal use in the warm season.

However, it is erroneous, since a well-insulated sloping mansard roof perfectly retains heat in winter, its temperature regime is no less comfortable than in heated rooms on the ground floor.

Even without additional thermal insulation, the attic is a kind of "air cushion" that maintains the optimum temperature inside the house.

A sloping mansard roof is considered a technically complex structure, and it is advised to entrust its construction to a professional team. Nevertheless, a person who is familiar with roofing works using the example of a traditional gable roof is quite capable of overpowering its construction with his own hands, with the help of two auxiliary workers, assistants. The main thing to understand is that this is a process that requires a serious approach, which is reckless to start without preliminary calculations.

Varieties of mansard roofs

Attic - a heated or cold space under the roof, which is used as a living space. According to building codes, in the attic it is necessary to equip windows for natural light and ceilings of sufficient height for a person.

Rooms under the roof, in which these conditions are not met, are called the attic. The following types of roofs are suitable for the attic device:

broken roof

Installation of a mansard roof suitable for habitation provides for mandatory thermal insulation, organization of natural light with the help of dormers or vertical windows and forced ventilation.

Benefits of a broken structure

Of course, the attic can even be equipped by building an ordinary triangular roof with your own hands. But due to the steepness of the slopes, in order for the ceiling to learn, the height of such a roof must be very large. This is not economical, and also impractical, because a roof with a variable angle of slopes allows you to more effectively manage the available space.

The flatter top makes the ceilings appear higher. According to building codes, if the distance from the floor to the ridge connection is less than 2.5-2.7 meters, the room is not considered residential, it cannot be called an attic, it is rather just an attic. The sloping roof design has the following advantages:

Possibility to build higher ceilings.
High level of protection against atmospheric precipitation, wind.
Light snow removal from slopes.
Helps to keep warm.
Rational use of roof space.

Construction stages

Create a project

When drafting a broken mansard roof for do-it-yourself construction, it is better to draw up drawings with different projections, which will comprehensively show the location of its elements. Based on the length and width of the house, you need to determine the size of the attic room, as well as the roof. First of all, the geometry of the slopes is built:

In order for the project calculations to be correct, it is important to accurately make primary measurements, as well as maintain scale. Computer programs can facilitate the design, into which it is enough to enter the dimensions of the building and the desired type of roof, they perform the rest of the work automatically. If there is no access to such software, it is better to use ready-made projects.

Calculation of the truss system

Rafters are the main supporting elements of a broken mansard roof, a kind of its backbone. They are subjected to enormous loads, so they are subject to special requirements.

The choice of the section of the rafter legs is not random, but in accordance with the installation step, the distance between the supports, the values of wind and snow loads. If the first three indicators can be easily determined from the drawn up drawing, then the last two need special explanation.

The territory of Russia is divided into 8 zones with different snow loads. For each specific roof, this value is adjusted by the angle of inclination of its slopes. Since the slope of the slopes is different, two indicators are calculated, respectively, the upper and lower rafters can have a different section.
There is also zoning for wind load, which also includes 8 zones. With the help of a coefficient that takes into account the height of the building, amendments are made to the tabular value of this indicator.
The values of these two indicators are summed to determine the total load. Numbers should be rounded up to provide a small margin of safety. Based on them, according to the reference tables, the required section of the boards is determined.

Mauerlat installation

The beginning of work on the equipment of a broken mansard roof - the installation of a mauerlat, a durable beam measuring 100x100 mm or 150x150 mm. It is fixed at the end of the side outer walls.

Its main task is to distribute the weight of the roof structure, transfer it to the foundation, as well as protect the slopes from tipping over. Mauerlat is laid on the upper part of the wall along a pre-laid waterproofing, which is used as a roofing material folded in half or several layers of a special film.

Fastening is carried out using metal studs, they must be placed in a concrete screed. If we are talking about the reconstruction of the roof with our own hands, it is mounted with anchor bolts to the wall to a depth of 15-17 cm.

For timber, as well as log houses, wooden dowels are used. Please note that the installation is flush.

Assembling the truss system

Assembly truss system of a broken mansard roof happens in the following order:

The fulfillment of the above points forms one truss truss. In the same way, the rest are installed in increments of 60-120 cm.

Waterproofing and roofing

When the do-it-yourself installation work is completed, you need to organize its waterproofing. This requires a waterproofing film or membrane, which is usually produced in the form of a roll.

Fasteners are selected depending on the type of material. For tiles, galvanized self-tapping screws with rubber heads are used, which are deformed in the process of twisting in such a way that they waterproof the hole.

In order to speed up the process, you can use a screwdriver. Shinglas or ondulin is fixed with nails 100 mm long. After the completion of the roofing work, gables and overhangs of the mansard sloping roof are drawn up.

Summing up, we can say that a broken mansard roof will help to expand the area of \u200b\u200bthe house with your own hands. You can build it with your own hands, however, this will require special skills and costs, which, no doubt, will pay for themselves.

Video instruction

A house with an attic is not only an additional living space, but also a respectable view of the entire building. Even if the room under the roof is made unheated and is used only in the summer, it still creates a powerful "air cushion" that helps to retain heat inside the entire capital building.

And about, then - read on our portal.

Attic project

When drawing up a scheme for building an attic, it is best to do this in different projections in order to see and understand the placement of all elements of the truss system. It is very important to correctly calculate the height of the roof ridge, since the size of the area under it will directly depend on it.

When drawing up a scheme-project for the construction of a mansard roof, you need to calculate the height of the ridge, the ceiling and the total area of \u200b\u200bthe room.

The minimum height from the floor to the ridge should be 2.5-2.7 m, if this distance is less, then the room is not an attic, it can only be called an attic. This parameter is set by the norms of SNIP.

In order for all elements to be drawn accurately and have the desired location in the overall system, it is necessary to start from a figure with right angles, that is, a rectangle or square - a section of the created attic room. Based on the sides (height and width of the future room), it will be almost impossible to make a mistake with the angles at which roof slopes are located, with the location of the ridge, rafters and all retaining elements. Determining these parameters, they must immediately be entered into the drawing.

First you need to find the middle of the width of the front wall. Starting from this point, the parameters of the height of the ridge, the future ceiling of the attic, the location of the rack-walls and the size of the cornice overhang are determined.

Due to the fact that each of the structures has a certain number of connecting nodes that have different configurations, it would be nice to draw each of these ligaments separately in order to understand their features of conjugation among themselves of all elements connecting at this point.

Any truss system consists of basic elements and additional ones, which may not be in every design. The main components of the mansard roof are.

Floor beams, which are the basis for the rest of the elements of the truss system. They are laid on the main walls of the building.
Rafter leg, straight in a gable roof system or consisting of two sections - in a broken pattern. In this case, the upper rafter is called the ridge rafter, as it forms the highest point of the roof - and the rafters that form the walls of the attic are called side rafters.
A ridge board or beam is an indispensable element for a gable roof, but is not always used when constructing a broken roof model.
Mauerlat - a powerful bar, fixed to the main side walls of the building. Rafter legs are installed on this element.
Racks are supporting elements necessary to strengthen a gable and broken structure. In the latter case, a ridge and side rafters are attached to it, and in the first case, the stand is a reliable support for a long rafter. In addition, the racks serve as a frame for insulation and sheathing of the attic walls.
Diagonal braces or bevels additionally hold the posts or stringers and rafters together, making the structure more durable.
Attic floor beams are used in all attic options - they connect the racks, and they are also the frame for the ceiling device.
Interrafter runs are installed in a broken form of the roof for structural rigidity.

To be sure that the prepared project is developed correctly, you need to show it to a specialist. Only he can determine whether the attic parameters are correctly selected for the width and length of the walls of the building.

Video: professional mansard roof calculation using special software

Parameters of materials for the construction of a mansard roof

If the graphic project is ready, then, starting from the dimensions marked on it, you can calculate the amount of materials needed to build a mansard roof. Materials must be selected according to their characteristics, which must meet the requirements of fire and environmental safety. For wood, it is necessary to provide special treatment with fire retardants, which will reduce the combustibility of the material. So, for the construction you will need:

Boards for rafter legs. Their cross section is selected according to the results of special calculations - this will be discussed in more detail below.
A beam having a cross section of 100 × 150 or 150 × 200 mm - for floor beams, depending on the chosen truss system and the width between the bearing walls, as well as for purlins, diagonal legs or valleys - if they are provided for by the design.
Beam with a section of 100 × 150 mm or 150 × 150 mm for laying Mauerlat.
For racks, a beam of 100 × 100 or 150 × 150 mm is usually used.
Unedged board for subflooring and some fasteners.
Annealed steel wire with a diameter of 3-4 mm - for fastening together some parts.
Nails, bolts, staples of various sizes, corners of various configurations and other fasteners.
Metal sheet with a thickness of at least 1 mm - for cutting overlays.
Lumber for battens and counter battens for roofing material - depending on the type of roofing chosen.
- for thermal insulation of the roof.
Waterproofing and vapor barrier membranes.
Roofing material and fasteners for it.

What section are required rafters

Rafters are roofing elements that will perceive the main external loads, therefore, the requirements for their cross section are very special.

The size of the required lumber will depend on many parameters - on the step between the rafter legs, on the length of these legs between the support points, on the snow and wind load that falls on them.

The geometric parameters of the design of the truss system are easy to determine in the drawing. But with the rest of the parameters - you will have to refer to the reference material and carry out some calculations.

Snow load is not the same for different regions of our country. The figure below shows a map on which the entire territory of Russia is divided into zones according to the intensity of the snow load.

There are eight such zones in total (the last, eighth, is more likely to be extreme, and it can not be considered for the construction of a mansard roof).

Now you can accurately determine the snow load, which will depend on the angle of the roof slope. For this, there is the following formula:

S = Sg × μ

Sg- tabular value - see the map and the table attached to it

μ — correction factor depending on the steepness of the roof slope.

If the slope angle is less 25° then μ=1.0
With a steepness from 25 to 60 ° - μ=0.7
If the roof is steeper than 60 °, then it is considered that the snow does not linger on it, and the snow load is not taken into account at all.

It is characteristic that if the mansard roof has a broken structure, then for its different sections the load can have different values.

The angle of the roof slope can always be determined either by a protractor - according to the drawing, or by a simple ratio of the height and base of the triangle (usually - half the width of the span):

The wind load also mainly depends on the region of construction of the building and on the characteristics of its environment and roof height.

And again, for the calculation, the initial data on the map and the table attached to it are first determined:

The calculation for a particular building will be carried out according to the formula:

Wp = W × k × c

W- tabular value, depending on the region

k- coefficient taking into account the height of the building and its location (see table)

The following zones are indicated in the table with letters:

zone A - open areas, steppes, forest-steppes, deserts, tundra or forest-tundra, open to the winds of the coast of the seas, large lakes and reservoirs.
zone B - urban areas, wooded areas, areas with frequent obstacles to the wind, relief or artificial, at least 10 meters high.
zone AT- dense urban development with an average height of buildings above 25 meters.

with- coefficient depending on the predominant wind direction (wind rose of the region) and on the angle of inclination of the roof slopes.

With this coefficient, the situation is somewhat more complicated, since the wind can have a double effect on the roof slopes. So, it has a direct, overturning effect directly on the roof slopes. But at small angles, the aerodynamic effect of the wind takes on special significance - it tries to raise the slope plane due to the emerging lifting forces.

In the drawings, diagrams and tables attached to them, the sections of the roof that are subject to maximum wind loads are indicated, and the corresponding coefficients for calculation are indicated.

It is characteristic that at slope angles up to 30 degrees (and this is quite possible in the section of ridge rafters), the coefficients are indicated both with a plus sign and negative, that is, directed upwards. They somewhat extinguish the frontal wind load (this is taken into account in the calculations), and in order to level the effect of lifting forces, it will be necessary to carefully fix the truss system and roofing material in this area using additional connections, for example, using annealed steel wire.

After the wind and snow loads are calculated, they can be summed up, and, taking into account the design features of the system being created, determine the cross section of the boards for the rafters.

Please note that the data are given for the most commonly used coniferous material (pine, spruce, cedar or larch). The table shows the maximum length of the rafters between the support points, the cross section of the board depending on the grade of the material, and the step between the rafters.

The value of the total load is indicated in kPa (Kilopascals). It is not difficult to bring this value into more familiar kilograms per square meter. With quite acceptable rounding, you can accept: 1 kPa ≈ 100 kg/m².

The dimensions of the board along its section are rounded up to the standard sizes of sawn timber.

	rafter section (mm)	Distance between adjacent rafters (mm)
		300	600	900	300	600	900
		1.0 kPa			1.5 kPa
higher	40×89	3.22	2.92	2.55	2.81	2.55	2.23
	40×140	5.06	4.60	4.02	4.42	4.02	3.54
	50×184	6.65	6.05	5.28	5.81	5.28	4.61
	50×235	8.50	7.72	6.74	7.42	6.74	5.89
	50×286	10.34	9.40	8.21	9.03	8.21	7.17
1 or 2	40×89	3.11	2.83	2.47	2.72	2.47	2.16
	40×140	4.90	4.45	3.89	4.28	3.89	3.40
	50×184	6.44	5.85	5.11	5.62	5.11	4.41
	50×235	8.22	7.47	6.50	7.18	6.52	5.39
	50×286	10.00	9.06	7.40	8.74	7.66	6.25
3	40×89	3.06	2.78	2.31	2.67	2.39	1.95
	40×140	4.67	4.04	3.30	3.95	3.42	2.79
	50×184	5.68	4.92	4.02	4.80	4.16	3.40
	50×235	6.95	6.02	4.91	5.87	5.08	4.15
	50×286	8.06	6.98	6.70	6.81	5.90	4.82
total snow and wind load		2.0 kPa			2.5 kPa
higher	40×89	4.02	3.65	3.19	3.73	3.39	2.96
	40×140	5.28	4.80	4.19	4.90	4.45	3.89
	50×184	6.74	6.13	5.35	6.26	5.69	4.97
	50×235	8.21	7.46	6.52	7.62	6.92	5.90
	50×286	2.47	2.24	1.96	2.29	2.08	1.82
1 or 2	40×89	3.89	3.53	3.08	3.61	3.28	2.86
	40×140	5.11	4.64	3.89	4.74	4.31	3.52
	50×184	6.52	5.82	4.75	6.06	5.27	4.30
	50×235	7.80	6.76	5.52	7.06	6.11	4.99
	50×286	2.43	2.11	1.72	2.21	1.91	1.56
3	40×89	3.48	3.01	2.46	3.15	2.73	2.23
	40×140	4.23	3.67	2.99	3.83	3.32	2.71
	50×184	5.18	4.48	3.66	4.68	4.06	3.31
	50×235	6.01	5.20	4.25	5.43	4.71	3.84
	50×286	6.52	5.82	4.75	6.06	5.27	4.30

Instruments

Naturally, during work, one cannot do without tools, the list of which includes:

Electric drill, screwdriver.
Building level and plumb line, tape measure, square.
Axe, chisel, chisel, hammer
Circular saw, jigsaw, hacksaw.
Carpentry knife.

Installation will be accelerated if the tools for work are of high quality, and the work is carried out with competent mentors, with assistants, carefully and in stages.

Installation steps

It is necessary to strictly observe the sequence of work - only under this condition the design will turn out to be reliable and durable.

Mauerlat mount

The installation of any truss system begins with fixing a powerful supporting structure at the end of the side walls of the structure. timber - Mauerlat on which it will be convenient to install rafter legs. Mauerlat is made from a high-quality bar with a cross section of at least 100 × 150 mm. It must be laid on the roofing material waterproofing laid along the upper end of the wall (regardless of the material).

Due to the Mauerlat, the load will be evenly distributed along the walls and transferred to the foundation of the building.

The Mauerlat is fixed to the wall with metal studs, which are pre-embedded in a concrete belt or a crown running along the upper edge of the wall, or with anchor bolts with a diameter of 12 mm. They must go deep into the wall by at least 150 — 170 mm. If the Mauerlat is installed on a wooden wall, then the bars are attached to it with the help of wooden dowels.

Installation of the truss structure

Installation of the truss system begins with the installation of floor beams. They can be mounted on the Mauerlat from above if the beams are planned to be taken out of the perimeter of the building and thereby increase the attic area. In this design, the rafter legs are fixed to the floor beams.

Floor beams fixed on top of the Mauerlat (Fig. A)

Otherwise, they may fit into waterproofed walls and fastened with corners or staples to the inner edge of the Mauerlat. This option is used when the rafter legs are planned to be fixed directly to the Mauerlat.

Another option - only rafter legs are attached to the Mauerlat

Next, you need to find the middle of the floor beam, since this mark will become a guideline for determining the location of the support posts and the ridge.
Racks should be located at the same distance from the marked middle of the floor beam. In the future, they will begin to determine the location of the walls of the attic room, that is, its width.
Bars for racks should have a cross section equal to the size of the floor beams. Construction sites are attached to the beams with the help of special corners and wooden linings. However, to begin with, they are first baited with nails, then carefully leveled with the help of a building level and a plumb line, and only then they are fixed thoroughly, with the expectation of future loads.

When the first pair of racks is installed, they are fastened together from above with a bar, which is called a puff. This puff is also connected to the racks using special metal corners.

After fixing the puff, you get a U-shaped design. Layered rafters are installed on it on the sides, which are attached to the floor beam with their second end or are laid on the Mauerlat.
A special notch (groove) is cut out on the installed supports for the timber or in the rafters. With its use the rafters are tightly installed on the mauerlat beam, and fastened with metal brackets.

For structural rigidity, struts can be additionally installed from the base of the rack to the middle of the installed side rafter. If this seems not enough, and saving material is not in the foreground, then you can strengthen the overall design with additional racks and contractions (they are indicated in the drawing in Fig. A by translucent lines).
Further, the middle is calculated on the puff - a headstock will be attached to this place, supporting the ridge connection of the upper hanging subsystem of the rafters.
The next step is to install ridge rafters, which can be fastened together with different connections - this can be a metal lining or powerful bolts with metal plates or washers.

After their installation, a headstock is attached to the ridge and the middle of the puff.
Having completed work on one part of the truss system, you need to make all the rest according to the same principle. The distance between adjacent rafters in such a system should be no more than 900 — 950 mm, but the interval of 600 mm will probably still be optimal - this will give both the necessary rigidity and stability of the structure, and will be convenient for insulation using standard mineral wool mats. True, this makes the structure heavier and requires more materials.

First, the side parts of the complete system are installed, and then the intermediate ones. Between themselves, they are connected by runs, which are installed between the upper ends of the racks and act as spacers. Thus, a rigid structure of the attic rafters will be obtained, in which the frame for wall cladding will already be ready.

Prices for various types of fasteners for rafters

Fasteners for rafters

Mansard roof waterproofing

When the truss system is built, you can proceed to finishing it and their accompanying materials.

The first coating to be fixed immediately on top of the rafters will be waterproofing and windproof film. it is attached to the rafters with staples and a stapler, starting from the eaves. Cloths are overlapped by 150 — 200 mm, and then the joints are glued with waterproof tape.
On top of the waterproofing, a counter-lattice is stuffed onto the rafters, which will more reliably fix the film on the surface and create the necessary ventilation distance between the windproof and roofing material. The counter-lattice is usually made of boards with a width of 100 — 150 mm and 50 thick — 70 mm.

A crate is fixed perpendicular to the counter-lattice, on which the roofing material will then be laid. The step between the rails must be calculated depending on the type and size of the sheet roofing material, taking into account the overlap required for it.
If a soft roof is chosen, then plywood sheets are most often fixed to the counter-lattice.

Roofing installation

Roofing material is fixed on the prepared crate or plywood. Its installation usually starts from the roof eaves and runs in order, from one of the edges - depending on the type of roof. Roofing sheets are mounted with an overlap. If a metal profile or metal tile is used for coating, then such material is fixed with special self-tapping screws with elastic gaskets. Fasteners are usually matched in color to the roofing material.

The most difficult thing in covering a mansard sloping roof is the transition from layered side rafters to hanging ridge rafters. There may be certain difficulties in the event that ledges are provided on the roof for roofing over balconies or windows.

In addition, if a chimney pipe enters the roof, it requires a separate opening inside the rafter system and the insulation layer, and on the roof, a reliable waterproofing device around the pipe.

How and what is better to cover the roof, you can find out in detail on our portal, there is a whole section in which you can find answers to many questions, including recommendations for reliable insulation of the attic room.

Prices for popular types of corrugated board

Decking

Video: a detailed video tutorial on building a mansard roof

It should be noted that the work on the construction of any roof, and even more so complex as an attic, is not only responsible, but also quite dangerous, it requires special, increased security measures. If there is no experience in carrying out such construction processes, then it is better to entrust their implementation to professionals or to perform all actions under the supervision of an experienced craftsman, and with the utmost care and accuracy.

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