Mansard roof with hanging rafters. Do-it-yourself mansard roof - drawings. Roofing materials and their fastening

Attic called the roof, under which the living rooms are equipped. The shape of the mansard roof can be different, but most often the attic is equipped under a gable roof. Most rational decision, allowing you to get the maximum usable area of \u200b\u200ba residential attic, is a mansard roof with a broken slope line.

The stages of building a mansard roof with your own hands are in many ways similar to the construction of a regular one, as well as the names of the elements that make up its frame. These include:

Mauerlat - a support beam that transfers the load from the rafters to the walls of the building;
Floor beams - boards that form the attic floor and the ceiling of the lower floor;
Racks - vertical supports supporting the truss system;
Runs - horizontal supports for rafters;
Rigel - transverse horizontal elements that pull the roof slopes together, otherwise they are called puffs;
Rafters - boards that form the main contour of the roof;
Suspension - a suspension rack that supports puffs and redistributes the load between the rafters;
Sheathing - boards or sheets of plywood designed for laying roofing over them and transferring the load to the rafter system;
Filly - boards fixed along the axis at the bottom of the rafters and designed to form a roof overhang.

The cross section of the roof elements is determined by calculation, the article presents the most commonly used materials in private construction.

The device of a broken mansard roof and its differences

As already mentioned, a roof with broken slopes is somewhat different from a simple one. gable roof. The difference lies in the shape of the opposite slopes: they are not a straight line, but consist of two slopes connected at an obtuse angle. The roof can be either symmetrical or have different shape opposite slopes - it depends on the project.

Thanks to the broken shape, the usable volume of the attic space is significantly increased. The lower part of the rafters is usually set at an angle of about 60 degrees to the horizontal, and the support posts supporting these rafters act as a frame. internal walls. The upper part of the rafters is most often installed at a slight angle, from 15 to 45 degrees - this allows you to save materials, but maintain the functionality of the roof and its resistance to snow loads.

Vertical racks resting on floor beams, purlins and puffs connecting them form a parallelepiped that limits the internal dimensions of the attic. To give the structure additional rigidity, struts are installed between the floor beams and the lower rafters. After installing the upper rafters, to strengthen the truss and eliminate the sagging of the crossbars, hanging supports - grandmas are installed. To further strengthen the lower rafters, they are pulled together with racks using contractions. The elements are fastened with nails and bolts or studs.

Calculation of the dimensions of the mansard roof

The main condition for a comfortable attic device is the height of the ceilings - it should not be lower than 2.5 meters. To ensure such a height of the room, the break line of the mansard roof must be at a height of at least 2.8 meters, taking into account the thickness of the insulation layer and the inner lining of the attic, as well as the thickness of the finishing floors.

Before you start buying materials and building a roof, you need to draw detailed drawing, which will indicate dimensions houses, the line of slopes and the height of the attic.

Drawing - mansard roof dimensions

The technology of erecting a broken mansard roof

Install the Mauerlat around the perimeter of the house. In wooden buildings, the upper beam or log serves as the Mauerlat. In stone - brick or block - structures, the Mauerlat beam is attached to studs or anchors fixed in the walls during masonry at a distance of no more than 2 meters. The Mauerlat is leveled along the inner plane of the wall, the wall remaining outside is later laid with decorative masonry. Mauerlat timber from dry softwood usually has a section of 100 or 150 mm. Saw off the beam of the desired length, straighten the anchor studs if necessary and lay the beam on top of them. Lightly tapping with a hammer. Dents from the studs remain on the beam, a hole of the required diameter is drilled through them. You can also mark the beam with a tape measure, but the probability of error in this case is higher. Laid on the wall roll waterproofing, you can use the usual roofing material in two layers. Mauerlat is put on the studs and the nuts are tightened.
For floor beams, coniferous timber with a section of 100x200 mm is usually used. Floor beams are placed either on top of the Mauerlat with an exit beyond the plane of the walls by 0.3-0.5 meters, or in specially designed pockets in the masonry. In the first case, the beams are fixed with corners and self-tapping screws. To make the floors even, the beams are laid in strict sequence: first, the extreme ones in level, then, pulling the cord, they align the intermediate ones along them. The step of the floor beams is usually from 50 to 100 cm, but the most convenient step is 60 cm, which allows you to lay the insulation boards without trimming. To equalize the height of the beams, they are hemmed or board linings are used. If the beams are placed in special pockets in the masonry, their ends must be processed coated waterproofing and wrapped with ruberoid. Align them in the same way.
Racks are installed on the extreme floor beams. The end posts are made of timber 100x150 mm, the height and installation line of the posts is determined according to a previously prepared drawing. Racks are leveled using a level and a plumb line and temporarily fixed with jibs in perpendicular directions - along and across the axis of the roof. This will allow you to install the racks without deviations in any direction. The jibs are made from any board and nailed. A cord is pulled between the extreme drains and the rest of the racks are set along it with a step equal to the step of the floor beams, that is, for each beam. All racks are fixed in the same way as the extreme ones. You should end up with two rows of uprights of the same height, running parallel to each other.
Runs from a board 50x150 mm are laid and fixed on racks, runs are fixed on nails 150 mm and on corners using self-tapping screws. Crossbars from a 50x200 mm board are placed on the runs with the narrow side down - this will increase their rigidity. Since there will be no load on the crossbar during operation, this section of the board is quite enough, however, in order to exclude their deflection and increase reliability during installation, when installing the crossbars, temporary supports from the board are placed under them no thinner than 25 mm. On top of the crossbar, they are fastened with one or two boards - also temporarily, before the installation of the rafters. At the same time, the boards should not be placed in the middle of the puff - there they will interfere with further installation, but retreating about 30 cm. After installing the racks, girders and crossbars, you get a rigid structure that limits interior spaces attic. To increase its strength, it is subsequently fixed with struts and contractions.
Installed from a board 50x150 mm. First, a template is made from a 25x150 mm board - it is easier and faster to process. A board of the required length is applied to the upper run, washed down the shape directly on the board and cut out. A template is applied to the run at the installation sites of the rafters, and if it matches everywhere, then the upper part of all rafters can be made according to the template. The lower part, which rests on the Mauerlat next to the floor beams, is cut out in place each time. The rafters are fixed with the help of corners and self-tapping screws and on nails.
To perform the upper rafters, it is necessary to mark the center of the roof. This can be done with a temporary stand nailed to the Mauerlat and an extreme tightening from the end of the roof so that one edge of the board runs along the center line of the roof. The rafters are aligned along this edge. Next, prepare a template from a board 25x150 mm, applying it to the edge installed board at the right level and to the run on which the lower rafters rest. Mark the top and bottom cuts and cut out the template. Apply it alternately to both sides of the roof, checking how accurately its center is marked. If the rows of racks are made in parallel, then there should be no problems with installing the upper rafters - they will all have the same size.
Execute according to the template required amount rafter legs. The rafters are installed on the girders and connected in the upper part with the help of overhead metal plates or board scraps for self-tapping screws. In the run, the rafters rest on the cuts and are fixed on the corners. In order for the rafters to stand straight, they are fixed with the help of struts installed with the lower end on puffs. So put all the rafters. fasten hanging racks- pieces of board 25x150 mm. The upper edge of the board is fixed at the junction of the rafters, the lower edge - to the puff.
They put struts under the lower rafters from a board of 50x150 mm, resting them with their lower oblique cut against the floor beam and fixing them on the corners, and the upper edge is attached to the side of the rafter leg, nailed to one or two nails, after which a through hole is drilled and fixed to a bolt or stud . After installing the lower struts, remove all temporary supports and racks.
Gables are sewn up, leaving door and window openings. If the floor beams are laid in the pockets of the walls, fillies are attached to the lower rafters - boards that continue the line of the rafters and form a roof overhang. When laying floors on top of the Mauerlat, the beams already protrude to the required distance, and there is no need for fillies.
corresponding to the type of roofing - solid or sparse. Waterproofing is placed on the crate and the roofing is installed, for example,.

A sloping mansard roof usually does not need insulation - only the walls and ceiling of the attic are insulated. The air space formed under the rafters ensures good ventilation of the attic, reduces the heating of the attic rooms in summer and provides additional thermal insulation in winter. Therefore, when sewing gables, it is important to leave ventilation windows in the upper part of the roof, above the floors of the attic floor.

Video - instructions for building a mansard roof

The construction of the attic is a very important process that is carried out both at the design stage of the entire house and after its construction. This room provides its owners with additional square meters of living space. On the features of the construction of the attic, we will consider further.

Attic construction: project and its development

The attic is a rather difficult part of the building to build. It is preferable to design it at the stage of building the house itself. Because, the construction of a residential attic already on a finished building is not always possible. First of all, due to the fact that the attic room has a considerable weight, and therefore loads the foundation.

The construction of the attic consists of a certain kind of stages, such as:

attic construction blueprints;
dismantling of old roofing materials, in the event that the attic is being built on an already finished building;
strengthening the walls on the upper floor, strengthening the foundation, if necessary;
erection of the walls of the attic room;
roof construction, its insulation, waterproofing and finishing;
installation window structures;
internal finishing works.

Compliance with all technological nuances in the construction of the attic will allow you to get a reliable and durable building.

The first and most important stage is the drafting of an attic room. At this stage, one should take into account such features as the size of the room, the material used in its construction, the roof and the level of its slope, and many other nuances.

There are three ways to design an attic. The first is the most budgetary, drawing up a project manually. However, this operation requires minimal design experience. The second way is to use ready-made project documentation, however, it’s not a fact that someone’s attic project is completely suitable for your home, so you still have to make some adjustments to it. The third way is to contact specialized organizations that, in the shortest possible time, will help you draw up an attic project for you, which is ideal for your home.

In the process of independent design, one should take into account the wall loads on the building, its appearance and finishing materials used both inside and outside the premises. In addition, it is imperative to take into account the load from the building on the foundation, it may need to be strengthened. If the attic is too heavy, then there is a risk of deformation or cracks in the house.

Experts will help you choose the best building materials, which, on the one hand, will ensure the durability of the attic in operation, and on the other hand, will help reduce its load on the base of the entire building.

In addition, after drawing up the project, it should be coordinated with special state institutions. In the presence of a competent project, this process will pass quite quickly.

Do-it-yourself attic construction in the house

We suggest that you familiarize yourself with the option of building an attic in an already built and commissioned residential building. In this case, the first step is to dismantle the old roof. Thus, it will be possible to expand the under-roof space, and increase the safety of the building under construction.

To dismantle the roof, it is not necessary to hire specialists, all work can be done by hand. To do this, you must first get rid of the external roofing finishing material. Next, you need to completely remove the crate and truss system.

After that, it is necessary to strengthen the walls on the adjacent floor, since the attic will exert a certain pressure on them. The design features of the attic put pressure not only on the surface of the base of the building, but also on its walls. Therefore, first of all, before the construction of the attic, it is necessary to strengthen the walls that lie close to it. To do this, you should use special calculations, according to which this process is performed and the level of strength of old walls is determined.

The next stage is the insulation and waterproofing of the attic floor, which is also the ceiling on the previous floor. With the help of this action, it will be possible to ensure a healthy atmosphere in the room. To insulate the attic, you can use various heat-insulating materials in the form of foam, mineral wool etc.

Attic construction photo:

This is followed by the process of building walls in the attic room. The walls are made in relation to the project developed in advance. Most often, wood or timber is used to build walls. To insulate the attic, it is recommended to use mineral wool or expanded polystyrene. Choosing material for external and interior decoration walls, try to give preference to materials with a high level of fire safety.

The next process is the construction of the roof. In this case, the calculation right angle roof slope is very important. Since too sloping roof will adversely affect the usability of the attic space. Please note that the roof must be properly waterproofed, since if there are the slightest leaks on its surface, moisture enters the attic.

In addition, the shape of the roof should be as simple as possible, the presence of broken and curly elements will only complicate the process of their construction. Also important is the issue of insulation of the attic. For these purposes, various types of Construction Materials. When choosing a heater for the attic, try to give preference to materials that do not absorb moisture, are resistant to frost, temperature extremes and rodents. In addition, the heat-insulating material should not allow heat to pass from the room.

It is best to focus on internal thermal insulation work. To form it, follow a series of steps:

install the finish in the form of a plasterboard or plywood base;
form a layer of vapor barrier; special films are used for these purposes;
lay insulating material - perfect solution- mineral wool;
ensure proper waterproofing of the roof with a special kind of membranes;
lay the outer finishing roofing material.

To build a roof, you will also need to install a truss system, mount a crate, the installation step of which depends on the type of roofing material. After the installation of the roof is completed, the windows should be mounted.

In order to provide high-quality lighting in the room, several windows should be installed in it, the size of which directly depends on the size of the attic itself. The window in the attic ceiling must be of high quality. It must be resistant to precipitation, wind, temperature changes. In addition, with the help of window structures, high-quality ventilation of the attic is provided.

Further actions for the construction of the attic are associated with the conduct of internal finishing works, organization of heating, decoration and design of the premises. Strict adherence to all recommendations for the construction of the attic will help ensure the long-term operation of this room.

Frame attic construction technology

Frame attic - perfect solution for any house, garage and even a bath. Among the advantages of frame-type attics, we note:

ease of construction, so it does not load the main building, there is no need for additional strengthening of the walls and base;
affordable cost of the attic - in comparison with its stone options;
high level of thermal insulation and sound insulation;
the possibility of building an attic of almost any shape and configuration;
ease of construction work, since the materials for the construction are quite light and no special equipment is required to raise them to the surface of the house.

construction frame attic allows you to get a finished building with excellent heat and sound insulation performance. In addition, the roof will remain intact, and the usable area of the premises will increase significantly.

A simpler process is the construction of an attic on a building that has not yet been erected. The construction of an attic on an already finished house requires the dismantling of the old roofing. Work should begin by studying the characteristics of the soil on the site and determining bearing capacity foundation. If the foundation is not able to withstand the attic, then it will be necessary to carry out a number of works aimed at strengthening it.

Next, you should examine the walls of the house for their susceptibility to additional loads. In this case, if necessary, it is necessary to strengthen the walls. After that, the old roof is dismantled and the ceiling is strengthened.

Construction wooden attic consists of the following steps:

production of a frame system;
wall installation;
performance of attic wall insulation;
installation work related to the installation of the roof;
attic finishing with roofing materials and roof insulation;
interior decoration of the attic.

In addition, the construction of the attic involves the installation of window and door structures, manufacturing and installation of stairs, etc.

In order to carry out the construction of an attic from a bar, it is necessary to prepare an edged board, plywood, self-tapping screws and the bar itself. The frame structure should be comfortable in height for the movement of an average person. Optimal value the height of the attic is at least two meters. The height of the ridge zone should be about 350 cm.

The easiest way is to assemble the frame on the ground, and then raise it to the roof. The top beam or frame frame will act as a hearth in the attic. For fixation frame structure on the surface of the house use special plates or plywood. Thus, it is possible to obtain a special platform. The knots and quality of fastening depends on the material from which the walls of the attic are made. Self-tapping screws are used to connect the timber in the upper part of the structure. After manufacturing frame walls the roof should be thermally insulated and waterproofed. After that, external and internal wall cladding is performed, windows and doors are mounted, internal finishing work is carried out.

When planning an attic, you should carefully analyze the general condition of the main building. The attic can be one room or will consist of several rooms. At the design stage, the design and shape of windows, as well as their location, should also be taken into account.

The attic should be built from lightweight, but at the same time durable materials. Since the materials should easily rise to the roof and exert a minimum load on the base of the building.

Most optimal materials for the construction of an attic - a tree or a steel profile. An attic made of stone or concrete will load the main building. Roofing materials should also be lightweight, but at the same time durable and reliable. It is preferable to use shingles or piece metal for roofing. We recommend using plasterboard for interior wall decoration and for leveling them.

Since the attic is located above the main building, it is more comes into contact with cold air. Therefore, it is necessary to ensure proper thermal insulation of this room. The heated air in the room should not penetrate through the insulation. In addition, in order to prevent moisture from entering the room, it is necessary to ensure its waterproofing.

In relation to the design features of the attic, it consists of a system of rafters, which is installed in compliance with a step of sixty centimeters. To fill the gaps between the rafter system, it is recommended to install heat-insulating materials such as mineral wool inside them. It is possible to lay insulation in one, two or even three layers. To calculate the total thickness of the thermal insulation material, the total heat loss coefficient in the room should be taken into account. To protect the roof from the inside of the room, a vapor barrier should be installed. Next, you should finish the roof with drywall, lining or finishing panels.

Do not forget to leave a ventilation gap, the main function of which will be to get rid of excess moisture in the under-roof space. The width of this gap depends on the type of roofing material. A vapor-permeable wind protection should be installed on the outside of the thermal insulation material.

An excellent vapor barrier material is polyethylene film, glassine or roofing material. The insulation is laid with an overlap of 15 cm. Construction tape is used to glue the seams. Please note that foil waterproofing is laid with a foil coating inside the room. Thus, the foil will reflect the heat that comes from the room.

Attic construction video:

As experienced builders say, an attic can be equipped in a house if there is a roof. The type of roof affects how much this measure will increase the usable area, whether it is comfortable to use this room and what complexity of work will be required. Common types of roofs for arranging a residential under-roof space are gable and straight and broken slopes.

The mansard roof rafter system is designed in such a way as to free up space in the center, where the height of the ceilings reaches an acceptable height, placing the bulk of the supporting elements at the edges. This article will tell you what the roof frame consists of, how to choose best option construction and proper installation.

Types of truss systems

Starting to design truss system for a mansard roof, pay attention to the layout of the house. Based on the types of supports, choose suitable option devices:

Layered. This type of truss frame is suitable for houses in which a load-bearing partition passes in the middle. Then the weight of the roof structure is distributed between it and the outer walls of the structure. This is an easy and rational way to organize the frame, but it is suitable if the distance between the outer walls and the inner support does not exceed 7 m.
Hanging. This type is used when there are no load-bearing partitions or columns inside, which are used to transfer the weight of the roof onto them. Hanging rafters are supported by a Mauerlat and a ridge run. For roofs up to 50 sq. m, with a small weight of the roof, the simplest configuration is used, consisting of rafter legs and a horizontal puff. To block a large structure, this structure is strengthened with racks, fights, struts. These elements increase the stability of the roof, but "eat up" the usable area of the attic. The permissible distance between the walls of the structure for hanging rafters is 14 m.
Combined. A mixed type of truss system is used when supporting columns are installed in the house instead of a supporting partition in the middle. It turns out that part of the rafters can be leaned on columns, and the rest can be mounted as hanging ones. This method is quite often used for arranging mansard roofs, as it allows the use of fewer auxiliary elements, reducing the load on the foundation and not cluttering up the roof space.

Please note that the attic installation must be planned at the project creation stage, because the type, weight and design of the truss system are necessary for calculating the foundation. If the decision to build a mansard roof arose at the final stage of construction, it is necessary to recalculate the mass of the house, taking into account new data, in order to check whether the foundation can withstand the additional load, especially if the site has complex soil and a small distance between the surface and groundwater.

Calculation of the elements of the truss system

According to building codes, a room is called residential if the height from the floor to the ridge is at least 2.5 m and there are sources of natural light, that is, windows. Therefore, the main parameter of the mansard roof that needs to be calculated is the angle of inclination of its slopes. The catch is that if you lay a slight slope, then the height of the ceilings in the attic will be lower than allowed by the rules. And, if you make covered slopes, the roof will turn out to be very heavy, expensive and unstable. Therefore, it is used, the slopes of which change the slope, its upper rafters have an acute angle of 30 degrees, and the lower ones - 60 degrees.

Tilt angle and ceiling height

An important stage in the design of a mansard roof is the calculation of the cross section of the elements of the truss system. The easiest way to find out the recommended size is in the reference tables with calculated values that take into account the length, the distance between adjacent elements, the type and quality of the material. However, if the roof is of a non-standard size, it is necessary to perform a calculation based on the calculation of the total load from the weight of the roof, which falls on the truss system. The calculation scheme also takes into account temporary loads in the form of a mass of fallen snow, which are reflected in the climatic coefficient characterizing the nature of the weather at the construction site.

To create a mansard roof truss system, wood is used, but this is not advisable in all cases, since in order for the rafters to cope with the load, it is necessary to increase the cross section of the lumber used, which further increases the weight of the structure. To break out of this vicious cycle, it is necessary to abandon wood in favor of stronger metal rafters.

Construction of the truss system

The components of the mansard roof truss frame are no different from the construction of other types pitched roofs. It includes:

In most cases, the elements of the truss system are made of high quality wood. To avoid deformation during operation, it must be dried to a moisture content of 15-18%, treated with antiseptic impregnation of deep penetration and flame retardant if you plan to bring the chimney to the roof.

Assembly sequence

The assembly of the truss system is best done using experienced craftsman, since even lifting heavy, long bars is problematic. It is not recommended to engage in installation in rain and snow, as the moisture content of the wood will increase during operation. The build process usually looks like this:

Reliability of the truss system mansard roof depends, first of all, on the correctness of the calculations, therefore, if you are not sure of your engineering abilities, it is better to use a typical project created by a professional architect.

Video instruction

A modern mansard roof is a great opportunity to significantly expand the living space of your home without any hassle. But, if you involve builders in the work, then this can cost a pretty penny. It is quite understandable that each of us thought about the question of whether it is possible to do everything on our own without experience. We assure you that a do-it-yourself mansard roof is more than real. We provide you with comprehensive instructions.

Currently the best option- broken attic. It is quite spacious and can really become a full-fledged living space with a large area. Naturally, for this you need to make accurate calculations.

Building a mansard roof will require you to consider many factors before. Let's list the main ones.

Video about the mansard roof of the house with your own hands

It is quite clear that the smaller the angle of inclination, the more usable space will be in your attic. But it is far from always necessary to strive for the most gently sloping placement. Here are some features of the choice:

If your house is located in a temperate area, where it is often windy and snow is rare, then you can safely make a roof with a slight slope;
If snowfalls and downpours are common in your area, a sloping roof should be discarded;
Do not forget that you need to take care of high-quality heat, sound and waterproofing. The attic is such a living space, like the rest of the rooms in your house;
The best roofing materials are tiles or slate. Many mistakenly put a metal coating, but with the advent of cold weather they face problems of heat conservation in the attic. Please note that the materials must be fireproof and moisture resistant. The roof always consists of wooden elements. In order to better preserve, it is recommended to treat all such surfaces with an antifungal solution;
An outdoor staircase for the attic will significantly save space in the house. An internal staircase is a much more convenient option, but it also takes up a lot of space. Great if you take care of installing a ceiling ladder. She practically does not take up space. As an alternative, you can install spiral staircase, but its convenience is often questioned.

An outdoor staircase for the attic will significantly save space in the house

To get started you will need wooden beams 10x10 cm in section. They are applied over waterproofing. The best material for her is roofing material or roofing felt, which is sold in rolls. Working with them is quite convenient and you do not need any additional skills. If your ceiling is also made of wood, then there is no need to lay an additional beam under the main beams.
The next step is to install the racks on the beams. The same bar with a section of 10x10 cm will suit you. These racks are a kind of skeleton of the walls of your attic. In order for them to fully fulfill their functions, they must be placed no further than two meters from each other. Make sure each one is perfectly level. We recommend checking each with a level and, if necessary, filing in the right places. When the racks are installed, they must be sheathed on both sides. For the inside, a great option is drywall or ordinary plywood, for the outside - slab. It is important not to forget at this stage to lay the insulation between the racks. Each rack is separately fixed with spikes and staples. So that at the same time they do not lean, we recommend that they be properly fixed with temporary braces.
Next, lay the top beam. Its cross section should be the same as in the previous paragraphs. You can fix it the way you want. But make sure that the beams are held firmly and firmly.

Each rack is individually secured with spikes and staples

Now you need to install the Mauerlat. This is a kind of support for the rafter leg, which is located at the bottom of the structure. For Mauerlat, you will need a beam with a section of 40x40 cm or a board with the same thickness. Thanks to the Mauerlat, high strength of the roof rafters to the walls will be ensured. It allows you to redirect the weight of the roof directly onto the walls. More than 40 cm cross section is optional. All the same, the Mauerlat lies directly on the wall and the load on it is relatively small. Just remember to put waterproofing under it, otherwise it will start to rot over time.
A well-mounted mauerlat protects your roof from the effects of wind, snow mass in winter and other loads. Therefore, make sure that it is fixed carefully. To do this, you can use a wire with a diameter of up to 5 mm. It is best to choose annealed wire, which is just designed for strapping. In order to make the walls more durable, the wire is embedded directly into them.
Now you need to install rafter legs. Make markings on the rafter frame and Mauerlat in places where the rafters will be installed. Usually the step is 1-1.2 m. For rafters, a board with a section of 4-5 cm and a width of 15 cm is suitable for you. Choose only perfectly flat boards. It is better to overpay a little money for them, but be sure that a do-it-yourself residential attic will not cause you to collapse the attic roof.

For rafters, a board with a section of 4-5 cm and a width of 15 cm is suitable for you

Rafter legs should rest on the ridge beam. If your attic has a large area, then the weight of its roof will be large. Therefore, the beam is an indispensable structural element. It is not needed only if the length of the rafter is less than eight meters. In this case, you can do with the usual stretch marks.
Filly installation. Produce it in the same way as the rafters. To simplify the process, start with the two extremes, pull the twine between them and align with it when installing the next ones.
Now it is necessary to nail the hem board to the fillies. It will become an obstacle to wind and almost any precipitation.
Before you make a mansard roof, you must consider where the windows will be installed. Remember that their area should occupy at least 12-13% of the area of the side walls. Where you decide to put windows, you need to strengthen the rafters. To do this, install the cross bars. They will take on the role of the lower and upper parts of the opening, where the window frame will be installed and attached.

Before you make a mansard roof, you must consider where the windows will be installed.

When the previous ten points are completed, you need to carefully double-check everything that has been done. Already at this stage, you will understand how to make a roof with an attic without any problems, but you always need to play it safe. Especially if you are doing it for the first time.

Carefully go through all the rafters and beams with a level, check whether they really hold tightly and securely, whether there is insulation everywhere, whether problem areas need to be finalized. It will be better if you ask one of the more experienced builders to assess with a trained eye whether everything is really done the way it should. Remember that the roof in your house must be safe and strong. But if everything is fine and the design is held securely, you can proceed to further work:

You have already created the roof skeleton. Now you need to nail the battens to the rafters. The pitch depends on which roofing material you choose for your roof.
When the crate is installed, a hydrobarrier must be installed on it. In most cases, plain plastic film works best for this. It is inexpensive, qualitatively protects the attic from moisture ingress and is easily attached with construction brackets. The main thing to remember is that the layers of the film must be laid from the bottom up with the layers overlapping each other.
A heat-insulating layer must be placed on top of the film. One of the best materials, which serves for these purposes - mineral wool. It is lightweight, retains heat well and is completely safe for your health, unlike many other heat-insulating materials. In addition, it effectively prevents the spread of rodents in your home.

On top of the film it is necessary to put a heat-insulating layer

When you get to the roof, proceed in the same way as in the case of plastic wrap. The roofing ball also lies from the bottom up, and the elements are superimposed on each other. Make sure that in those places where there is a break in the roof, the upper ball of the roof protrudes above the lower one. It is very important. Otherwise, with the slightest rain, your roof will leak, and the structure will gradually rot.
The installation of the ridge should take place in such a way that its design completely excludes the possibility of rain falling under the roof of your roof.

Completion of installation

The main part of the work has come to an end. It is recommended to make mansard roofs multi-layered so that they provide the best heat, noise and waterproofing of the entire attic. Do not forget also that the attic must "breathe". modern windows and doors are an essential element of any such roof.

If you have not fully decided on the installation of stairs, then for a start it is better to install an external one. It will be cheaper and easier that way. In any case, if you feel that this option does not suit you, you can make a staircase indoors at any time, sacrificing space in the house.

Video about a gable roof

Now you know how to build a mansard roof according to all the rules and not resort to the help of an expensive team of builders. Be patient, choose quality materials and tool, and then follow our instructions. Good luck!

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 gable system roof or consisting of two departments - 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.
beams attic floor are used in all variants of the attic - 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 selected rafter system and the width between bearing walls, as well as for runs, 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 different 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 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 broken structure, then for different parts of it, 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 specific 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 IN- 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 special meaning takes on the aerodynamic effect of the wind - it tries to raise the plane of the slope 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 very 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 design features created system, 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 maximum length rafters between support points, the section of the board depending on the grade of the material, and on the step between the rafters.

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

The dimensions of the board according to its section are rounded up to standard sizes lumber in a big way.

	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

Tools

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 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 chosen soft roof, 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 used for coverage metallic profile or metal tile, 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 the attic broken roof- this 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.