DIY broken roof. DIY sloping roof: drawings, calculations, photos, videos How to build a sloping roof step by step instructions

Particular importance has recently been attached to increasing the functionality of buildings while maintaining an attractive appearance. These goals are precisely served by a do-it-yourself sloping roof, which allows you to additionally create living space by organizing an attic space with maximum comfort. A sloping roof is a type of roof that is one of the most difficult to design and build. However, it doesn't this type roofing is less popular.

Sloping roof concept

Roofs are called broken because of their shape and the large number of broken lines. At its core, a sloping roof is a type of gable roof, which allows you to get on the attic floor large area living space. But for many developers, organizing additional space is not very important; they simply like this roof shape better than the traditional gable roof.

Another advantage of building a sloping roof lies in the possibility of obtaining on the attic floor high ceiling. That is, such a structure can be made higher than an ordinary gable structure, which often cannot withstand wind loads due to too steep angles of inclination. Such opportunities are provided by a fracture on the slope: the upper part, which is more vulnerable due to the perception of wind load, has a slight slope, but the lower part drops sharply down.

Sloping roof device

The hipped sloping roof is the most popular, because it is this design that ideally combines the low complexity of constructing rafter systems and the maximum efficient use living space. With this approach, with a minimal investment of money, you can additionally get full-fledged rooms that are completely suitable for living at any time.

The installation of a sloping roof implies the presence of fairly large rafter structures, but since it is customary to use a modular installation method during its construction, the entire system can be assembled without the use of complex lifting equipment. The posts and rafters are cut at a certain angle where the slopes break. To fasten the components of the entire system, plywood “kerchiefs” are used, which have a thickness of no more than 2 centimeters.

Similar design a hipped roof is great for houses with relatively small dimensions, where it is not possible to broken roof complex shape. And for large buildings they usually create a slightly different rafter system.

Types of sloping roofs

There are several types of sloping roofs depending on the number of slopes: single-pitch, double-pitch, three- and four-pitch. As a rule, the comfort of living in a house, as well as the reliability of the building, depend on this parameter.

The sloping roof includes 2 broken slopes. A pitched roof is a kind of inclined plane fixed to walls of varying heights. This solution is the most common, because it involves creating a fairly simple rafter system.

A gable roof consists of 2 slopes directed in diametrically opposite directions. This type of attic organization is also very popular. And all because this type of roofing is of very high quality in use. Vaulted roofs are usually typical for residential buildings rectangular shape.

The three-pitched sloping roof at the end has 1 vertical wall, and the second end is made with the same profile breaks as the side slopes of the roof. This design is lighter due to the absence of one main wall. In addition, a gable roof is installed when the attic roof is connected to the roof of another part of the residential building.

The hipped roof has broken profiles along all 4 slopes of the wall. This is the most difficult option for sloping roofs from a technical point of view. But they are the lightest in weight.

However, if it is important for the developer, then you can make a heptagon. But sloping roof projects with such a profile break are used extremely rarely in practice due to the difficulties that arise in the installation of rafters and installation of the roof covering.

Not only houses, but also balconies (loggias) in an apartment can have a roof, including a panoramic one. Entrust installation better for specialists. Unique glazing of balconies with roofs of any complexity.

Sloping roof shape

The shapes of a sloping roof can be completely different. Such roofs in most cases have the shape of a parabola and are most often found in private rectangular houses. The slopes have a trapezoidal shape along the long sides and triangular shape in short Often, drawings of a sloping roof and its rafter system are much more complex, and diagonal rafters appear in them.

Semi-hip structures are considered a type of hipped sloping roof. The half-hip is a kind of end slope; the end of a gable roof does not cut it off entirely, but only its lower and upper parts.

The roof at the bottom has the shape of a trapezoid, and at the top - a triangle. TO hip roofs include such varieties as conical, domed and pyramidal structures. Such sloping roofs are often installed for buildings of round and polygonal shape.

Construction of a sloping roof

Despite all the complexity of a sloping roof, the structure can be built with your own hands. Having decided on the dimensions of the product and the layout of the sloping roof, you can begin its construction. Attic structures have many features that distinguish them from other roofs. If installed incorrectly, the roof may leak, have poor ventilation, and rainwater, ice and snow may accumulate on top.

Material selection

It is recommended to make the rafter structure for a sloping roof from wooden materials, which helps to significantly lighten the supporting structure. In this option, the use of reinforced concrete structures and metal profiles not advisable.

To form a rafter structure, a wooden beam is required, which has optimal humidity. Wood is predominantly used for construction coniferous species as inexpensive and the most soft material. To form the sheathing you need an edged board.

The lighter the weight of the roof, the more reliable the entire broken roof will ultimately be. Such materials include metal tiles, soft roofs, galvanized iron and reed sheets. The connection of rafter structures is made using metal brackets and brackets secured with self-tapping screws.

Size calculation

Before building a sloping roof, a fairly accurate calculation should be made. The slightest errors in the distribution of loads can provoke poor-quality creation of a supporting structure that will not support the entire weight of the roof and rafter legs. To make the calculation correctly, you need to have on hand: a roof design project, a calculator and a tape measure.

Accurately measure all the dimensions of the sloping roof and transfer them to the sketch. It is better to divide a roof of such a plan into several different geometric shapes - trapezoids, rectangles and triangles. Next, measure the area of ​​each figure, and by summing them up you can find out total area mansard roof.

So that during the construction process you do not encounter a shortage roofing material, you need to produce it detailed calculations. This will also help you save money without overpaying for extra material. You already know the total area of ​​the roof, so you can easily calculate how much sheets of roofing material will be needed to construct it. When calculating, you need to take into account all the subtleties roof frame and the presence of cornices with skates.

Wood protection

Before making a sloping roof and forming rafters, it is recommended to protect the wood from excessive dampness and take care to prevent processes that support combustion. To do this, it is necessary to treat all structures with antiseptics and fire-fighting compounds before installation.

In the arsenal of protective equipment today there are many compounds that prevent rotting wooden structures. Apply the compounds in several layers using a wide brush so that they penetrate as deeply as possible into the wood. When working with similar active substances It is worth protecting your hands and respiratory organs with a mask and special gloves.

Location of floor beams

Before you start placing floor beams, you should definitely watch a video about a do-it-yourself sloping roof. Then install the wall plate and floor beams. Select the cross-section of the floor beams as 100 by 200 millimeters. Along the two lines of the rack, align the outer beams of the timber strictly vertically, then tighten the laces and install the intermediate ones.

A distance of no more than 3 meters is allowed between them. All racks are usually secured with temporary spacers. The height of the racks is selected 10 centimeters more than the planned height of the ceilings in the rooms.

I would like to note that when they do new roof on an old house, often when looking from above at the laid out floor beams, a strict rectangle does not appear. In order to facilitate the work, it is necessary to place the racks in such a way that they necessarily form a rectangle.

Side wall frame

Place the purlins from the board on top of the posts and install the remaining posts. The resulting structures will serve as the future frame of the side walls of the attic. Install and attach tie rods to the purlins. It is customary to place a temporary support under each of them in the middle of the span, so that when installing the rafters of the upper slopes, you can safely walk on the strings and not be afraid that they will break.

After installing all the ties, fasten them on top with a board, and the structure will become more rigid as a result. Following the instructions on how to properly build a sloping roof, you should install the side rafters and plugs for the insulation, after which you can begin installing the rafters of the upper slopes.

Installation of the upper slopes

First you need to make a rafter template. Take required trim boards and secure it temporarily on the outer crossbar in vertical position. One of the upper corners of the board must exactly coincide with the geometric center of the sloping roof. Make 2 rafters according to the template and install them, securing them with a brace.

Next you need to install all the other rafters. If you are interested in how to build a sloping roof according to traditional version, then remember that it is enough to install 4 struts on the roof - 2 in different directions. Temporarily fasten the remaining pairs until the sheathing is created with an inch board. According to the drawing, hangers are sewn on, which prevent the ties from sagging when you remove the temporary supports.

After this, you need to install the pediment frame and sheathe it, make cornices, sheathing, gable ebbs and overhangs. Next comes the turn of roofing work. After connecting all structural elements, they need to be further processed to prevent the harmful effects of moisture.

Waterproofing and roof insulation

To create a comfortable atmosphere in the attic space and reduce energy costs for heating the room, it is worth taking care of waterproofing the roof. It is preferable to use a special “roofing pie”, which allows you to create optimal humidity. You can find out what it looks like by watching a video about a sloping roof.

First install a special roofing or waterproofing film on the sheathing. Place any insulation on top of it - bulk, rolled or in mats. Place a layer of roofing felt on it, which must be attached to the sheathing using dowels. Then the second row of sheathing is placed.

Roofing

After the sloping roof is made, and construction works The insulation and waterproofing of the roof is completed, it’s time to select the roofing material. Regardless of the fact that the roof of a sloping roof has several angles of inclination in its design, it is customary to install the roofing material using conventional technology.

The sheathing system is applied to special counter-battens, which allow for natural ventilation of the roof. When organizing the sheathing, you need to ensure strict compliance geometric dimensions in order to facilitate the installation of roofing material, which should be carried out in accordance with the requirements of SNiP and technology recommended by manufacturers.

It is not advisable to cover such roofs with copper tiles or iron, because the room becomes very stuffy and hot in summer, despite the presence large quantity windows After installing the roof, you can begin installing gutters.

Roof drains

When installing a sloping roof, drainage is absolutely necessary. Their purpose lies in draining water that flows from the roof from the foundation and walls of the building. The lifespan of a house without drainage will be extremely short. Drains for a sloping roof can be made of plastic, non-ferrous metals or galvanized steel. Some manufacturers cover such drainage systems with special polymer coatings, increasing the resistance of the material to corrosion.

Today you can also find plastic drainage systems on sale, which differ low level cost, low weight, low noise level under wind load, various color and design options. Modern plastic systems for water drainage are resistant to temperature changes.

Of course, in the photo of broken roofs, drainage systems made of non-ferrous metals - copper, aluminum or titanium - look more attractive. Moreover, they are characterized high level corrosion resistance. But their cost is too high for the average developer.

Installation of roof windows

Without natural light the attic will not become a full-fledged living room. It is necessary to install skylights that have special frames that are subject to fairly stringent requirements. Since such structures are usually installed in the roof, their design must imply excellent waterproofing, because they are subject to heavy loads from precipitation.

Dormer windows are usually made of PVC or wood. Double-glazed windows for such structures must be energy-saving; they are covered with a special film that can protect them from damage and dirt. The window opening mechanism should also be convenient, because they are quite difficult to clean.

Attic glazing is characterized by its own characteristics. The window area with vertical lighting should be 1/8 of the roof area. This ratio with built-in windows reaches 1/10. Windows can be installed in one or several rows, they can be combined.

An important point during installation skylights the sealing of the slopes protrudes - they protrude slightly above the surface of the sloping roof. It is advisable to install special spacer bars that should be located between the vapor barrier film and the drywall. This will prevent condensation and create the required air flow. The vapor barrier film itself should be installed along the entire contour of the attic and windows; there should be no extra holes or cracks in it.

Thus, the construction sloping roof- a rather complex technological operation, and if you do not have the appropriate skills, you should entrust this work to specialists. But if you are determined, our recommendations and instructions, which cover the question of how to properly make a sloping roof, will help you independently implement the project and allow you to build a beautiful sloping roof with minimal investment.

A sloping or mansard roof is one of the popular and common types of roofing. It is particularly effective and convenient when the attic involves the arrangement of a living room. The break in the slopes provides significant additional space, with the upper level serving as a roof, and the lower level becoming the walls for the room.

A house with a sloping roof is quite common in our country. This type of roofing is widely used both for covering private houses and dacha construction. Frame house often happens with a sloping roof. This is explained by the peculiarity that the frame structure does not involve the construction big house, and the attic roof helps to make maximum use of the space on the second floor to create another living room in the country house.

A broken roof is quite simple to construct, although it requires special calculations during its design. With some experience, you can build it yourself. In this article we will look at how to build a sloping roof with your own hands.

In this article

Design

A sloping roof requires preliminary calculation of all elements. Design is carried out in two stages:

The rafter system of a house with a sloping roof is calculated taking into account the weight of the finishing coating. Calculation required quantity roofing is done by calculating the roof area. This roof consists of four planes in the form of rectangles, its area will be equal to the sum of their areas.

It is important not to forget to add 15% to the resulting number to form joints of the roofing material and unforeseen situations.

Having calculated the area of ​​the roofing material, it is not difficult to find out its weight and, in accordance with this, design the rafter system as capable of holding this roofing material. In addition to the weight of the roof itself, when designing a rafter system it is necessary to take into account:

• Lots of other elements roofing pie: insulation, insulating materials, lathing;
• The length of the rafter legs, the pitch of the rafter system and sheathing;
• The slope of the roof slopes, the height of the ridge;
• Temporary loads on the roof, such as the weight of builders, roof windows (if they are planned), various fences and abutments.

Choosing the slope angle of roof slopes is one of important points design, which is based on a number of factors:

• Type of roofing;
• Wind load and precipitation intensity of a particular region.

Classic angles of inclination of slopes of a sloping roof are located within the range of 35-45° for upper tier and 60° for the lower one.

It must be taken into account that if the under-roof space is used for a living room, then the height of the ridge cannot be less than 2.5 m.

If you plan to add an extension to a house with a sloping roof, we recommend adding this to your plan in advance. As a rule, such extensions are covered pitched roof, which is like a continuation of one of the lower slopes of the roof.

If the design of the house requires a roof with a balcony, then it is advisable to extend the roofing so that the balcony is under its slopes and is not subject to the destructive effects of precipitation.

Selection of materials

After completing the calculation work, you can begin to select materials for constructing the roof. Broken roofs suggest enough standard approach to the formation of the roofing pie and selection building materials:

• The Mauerlat and purlins are made of strong thick beams with a section of 200*200 and 50*100 mm, respectively;
• Rafter legs are formed from beams 50*200 mm;
• To create counter-lattice and sheathing, boards with a smaller section of 50*50 or 20*90 mm will be used;
• To create a warm room under the roof, you will need 200 mm thick insulation, as well as hydro- and vapor barrier materials.

A broken roof and its strength depend not only on the accuracy of the calculations made and the choice of building materials, but also on the quality of the wood. We recommend choosing beams and boards of coniferous trees with a moisture content of no more than 20-22% without cracks and knots.

Before the beginning installation work All wooden elements They must be coated twice with special antiseptic solutions that protect the wood from rot and pests. A roof constructed from such materials will be durable, solid and will last for decades.

It is important to decide on the roofing material before starting installation work, since a number of important features of the rafter system, such as the pitch of rafters and sheathing, depend on its type. Mansard roofing is compatible with any type of roof, as it has a fairly simple geometry and does not result in a large waste of materials.

Installation

So, how to make a sloping roof? Construction mansard roof on its own requires compliance with a number of rules. Let's take a closer look at how to build this type of roof, such as a sloping roof, step by step with your own hands.

Installation of the Mauerlat and rafter system

The Mauerlat beam is attached along the top of the walls to specially prepared studs. The optimal pitch between studs is approximately 2 meters. The Mauerlat bars are additionally secured to the walls with a wire tie. To protect the walls from moisture, it is necessary to lay a layer of roofing material under the Mauerlat.

The next step is to lay the floor beams, which will serve as the frame for the vertical posts of the rafter system. The beams can be laid on a mauerlat secured with iron corners or in pre-made recesses in the masonry walls.

When laying beams, it is important to maintain a horizontal level.

Installation of the rafter system begins with vertical rafters with level control. Next, purlins secured with iron corners are placed on the racks. The parallel racks are fastened together with ties, which can be reinforced with struts for additional support.

The lower tier of rafters is supported by a mauerlat and purlin. The rafters are pre-cut at an angle and secured to the support with plates. Strengthening the lower rafter legs is done with struts, the lower edge of which is installed at an angle on the beam, and the upper edge is mounted to the rafter with a bolt.

The upper rafters are also pre-cut according to the template. At the top they are connected by boards or plates, and bottom are inserted into the purlin with fastening with corners. The rafter legs are additionally strengthened with a stand to the place where the rafters are fastened and tightened.

Insulation, lathing and roofing

After installing the rafter system, roof insulation work is carried out. Waterproofing with an overlap is laid on the rafters from the outside roll material 10-15 cm. The material is attached to the rafter legs with nails. Next, the work moves under the roof. Layers of mineral wool are laid between the rafters and covered vapor barrier material. The entire structure is sewn up from the inside with construction cardboard for finishing the interior.

From the outside, a counter batten is placed on the waterproofing layer and then lathing with a pitch corresponding to the type of roofing material chosen.

The roofing material is laid in accordance with the installation rules for the selected type of roof, but in general terms it repeats the basic rules: laying from the bottom of the slope to the top.

We figured out how to make a sloping roof on our own. By following our instructions, you will receive a strong and reliable roof that will delight you with its efficiency and convenience for many years.

Broken roofs belong to the category of popular and most effective roofing structures. The construction and arrangement of such a roof requires the contractor to have certain skills in performing the necessary calculations and relevant measures.

However, having understood the basic provisions of the manual, it will be possible to cope with the arrangement of such a roofing structure on your own without the involvement of third-party specialists, which will allow you to save significantly.

A sloping roof is perfect for situations where it is planned to equip a residential attic. IN in this case the under-roof room will have fairly high ceilings.

It is somewhat more difficult to erect a sloping roof than an ordinary one- or gable structure, however, as you already know, there are no impossible tasks.

Broken roofs look best on buildings that have a square shape. If your house is narrow and long, there will be practically no benefit from the attic, and therefore from the roof structure in question.

Any roofing structure, and the broken line is no exception, are calculated in two stages. When performing the first calculation, the required amount of finishing material is established, and the second calculation is intended to establish the load-bearing capacity of the rafters.

Drawing - dimensions of the attic roof

The first calculation is performed using the geometric dimensions of the roofing system. Calculating the load-bearing capacity of the rafter system is somewhat more complicated. When performing it, you need to take into account the following indicators:

Having received all the listed data, you will be able to calculate the rafter system using the appropriate formulas or special programs, which is simpler, faster and more convenient.

Based on the calculation results, you will determine whether the sections are suitable structural elements specifically to your roofing structure. If necessary, the characteristics of the sheathing and rafter legs can be changed. You can also replace the roofing material.

For maximum convenience create 3D model future broken roof structure with the parameters you have chosen. Special programs will help you with this.

What to build a roof from?

After completing all calculations and preparing the necessary project documentation, you will know what the cross-section of the elements of the roof truss system should be, what kind of sheathing is best to install and what roofing material is suitable specifically for your case.

Go buy the necessary equipment.

First of all, buy timber for arranging the mauerlat, as well as beams or boards for installing sheathing and edged board for the rafter system. Rafters can also be made from timber.

Perfect fit coniferous wood. It is important that the moisture content of the material does not exceed 20-22%. The material should not have large knots. Traces of damage by bugs and bluish spots should also be absent.

Consider the fact that the strength, reliability and durability of the broken roofing structure directly depends on the quality of the wood.

Before using the purchased material for its intended purpose, be sure to treat it with an antiseptic. Special means will protect the material from rotting. Also, periodic treatment with antiseptics will need to be carried out throughout the entire period of use of the roofing structure.

In addition to antiseptics, all wood must be treated with fire retardants - these are special fire-fighting agents.

Process the material outdoors or in a well-ventilated area. Be sure to wear protective gloves and a respirator. The mentioned products are applied in a double layer. For application it is most convenient to use a sprayer; ordinary brushes are also suitable.

After applying the impregnations, let them dry completely, and only then proceed to other planned activities.

Also, to equip a broken roof structure, you will need fasteners - screws, plates, bolts, etc.

Additionally, purchase suitable materials for waterproofing, insulation and vapor barrier of the structure, as well as finishing roofing material.

The procedure for constructing a roof

The arrangement of the structure in question is carried out in several simple steps.

First step

Secure the Mauerlat to the upper strapping beam.

Second step

Install the rafters as required by your design drawings. Pre-cut templates for connecting the rafter elements with the support beam (mauerlat).

Third step

Expose vertical racks and secure them to the floor beams. They will take over the function of the frame of the walls of the future under-roof room.

At the top, tie the posts together using purlins. These elements will simultaneously take on the functions of tie-downs for the upper rafter elements and ceiling beams for the attic space.

Perform further work according to the requirements of your project. In this case, be sure to take into account that the rafters, due to which a vertical roof slope is formed and the tightening of the upper rafter legs with the Mauerlat is ensured, must be layered. The upper rafters in the design of such a roof will be of the hanging type.

For additional rigidity of hanging rafter legs, provide fixation on the headstocks. They must be connected to tie rods that serve as beams for the ceiling of the attic floor.

If necessary, install spacers and struts. All listed structural fasteners should be initially marked on your roof drawings.

On the outer rafters located at the ends of the house, install additional frames to accommodate gables, doorways and double-glazed windows.

Insulation work and finishing

Finally, all that remains is to install the necessary insulating materials. First fasten to the frame of the roof structure vapor barrier film, laying it along the rafter legs and securing it with a stapler. Attach the film with an overlap, without excessive sagging.

Install the timber sheathing. Select the lathing pitch individually in accordance with the characteristics of the selected finishing coating. In some situations, a metal profile is used to arrange the sheathing, but the option using wooden beam is the most common.

Lay down thermal insulation material(preferably mineral wool) between the rafter elements. Place the insulation in a spacer. From the attic side, additionally secure the insulation with lathing. In the future, the final internal coating will be attached to it.

Lay waterproofing material. The principles of installation and fastening are the same as in the case of a vapor barrier membrane. Proceed with laying the finishing material on top of the installed moisture insulation. The slopes of the design under consideration are based on a broken profile, therefore finishing coat Installation should begin from the bottom.

At the junctions of the roof slopes, lay the top row of finishing material so that it overlaps the lower tier and creates a kind of canopy over it.

Laying roofing on an attic roof

Finally, it is necessary to install various additional elements of the roof structure such as gutters, fences, etc.

A finished broken roof structure, created on our own, is in no way inferior to similar buildings equipped with the help of professionals.

Good luck!

Video - Do-it-yourself sloping roof

The popularity of sloping roofs is due to the cost-effectiveness of construction and the ability to rationally use attic space. They are used to organize insulated and non-insulated attics. The technology for constructing roofing structures with variable slope angles differs from the traditional gable scheme.

Because those who want to acquire attic floor To successfully prove yourself in the field of a roofer, you need to know how the rafter system of a sloping roof is structured and how the dimensions of the materials for its construction are calculated.

The most striking and expressive representative of the class of sloping roofs is a pentagonal structure with a clear difference in the angles of inclination of the slopes. Even without delving into the specifics of its construction, one can understand that it is made of two tiers stacked on top of each other. In the lower solid tier there is an attic, which gave the second name to broken roofs. The less voluminous top tier, crowning the lower part, determines the shape of the structure in the ridge area.

Briefly about the specifics of the rafter structure

The rafter frame for both parts of the attic roof is constructed according to the rules dictated by the usual one. The lower part of the sloping roof frame is built by installing layered rafter legs. In the construction of the upper part, both layered and hanging rafters can be used. The bottom of the layered rafters has the right to rest on the mauerlat or on the floor beams. The support for the top is most often a wooden frame, which at the same time plays the role of a frame for one of the walls of the attic. The design of the upper tier is focused mainly on ease of use for the performer.

According to tradition, the angle of inclination of the slopes of the lower part of the sloping roof is much steeper than the upper one. They create a break - a clear indicator of application broken technology in roof construction. However, the steepness of the upper and lower parts of the slopes may be equal, which is why the broken structure will look like an ordinary gable. But they are installed using the standard method for sloping roofs, because the frame of the lower tier must ensure the possibility of organizing the usable space. Those. the rafter system must have necessary elements with a given load-bearing capacity for constructing the walls and ceiling of an insulated or cold attic.

Types of loads and their combination

We will not give the intricate formulas according to which the sloping roof truss system is calculated by the designers of construction enterprises. The builders know them without us. Those who decide to build one or two roofs on a suburban area do not need such fundamental information at all. There are plenty of programs on the Internet that perform complex mathematical operations in a couple of seconds to calculate the cross-section of rafters, supports and beams. Let’s better understand what data will be required to be entered into the program, as well as what types of loads on the floor, rafters of the upper and lower tier should be taken into account.

Download the program itself here -(you only need Excel to work). Further we will give examples of working specifically with it.

Why are limits needed?

Each element of the sloping roof truss system will be affected by different kinds loads The sum of the loads should not lead to deformations and damage requiring mandatory repairs. Bearing structures According to the rules, they are calculated taking into account two limit values, these are:

• Ultimate strength is a condition, exceeding which leads to destruction. building structure, to loss of endurance or stability.
• Limiting deformation is a condition, the excess of which leads to unacceptable deflections, as a result of which not only the geometry of the structure changes, but the nodal joints are disrupted.

For both types of these limit states, designers make calculations. An independent roofer does not need these subtleties too much. The calculation programs available on the Internet with their formulas already take into account the limits. They are entered into the calculation algorithm in the form of signal values ​​of the type:

• N tr. strength - the size of an element of the rafter system, a decrease in which will lead to a loss of strength.
• N tr. deflection is the size of an element, the reduction of which will lead to threatening deformation.

When turning to automatic computing help, you need to pay close attention to such values. This is an extreme minimum indicating that actual design values ​​should be higher.

The list of loads acting on the roof includes the weight of winter precipitation, wind force, dead weight, the weight of furniture and people using the attic. Loads can act simultaneously, alternately or in any combination such as snow + furniture + people; snow + wind, etc. Calculations are carried out to the maximum in an effort to provide for the likelihood of exposure to the greatest load.

How to determine the weight of snow cover

To determine the weight of the snow cover, you do not need any special knowledge. It is carried out by determining whether the construction site belongs to a specific “snow region”. We found a region on the map with a number assigned to it, then looked at the sign to see how much snow would press on the horizontal surface.

For the rafters of the upper and lower tier of a sloping roof, the snow weight indicators will be different. The slopes of a sloping roof in most cases are unequal in angle of inclination. In solid precipitation more possibilities linger and lie on the closer to the gently sloping top than on the steep slopes of the lower part. It should be taken into account that on slopes with a steepness of up to 30º, the weight of snow is taken equal to one unit of the average value accepted in the region based on long-term observations of the weather service. It is believed that on slopes with a steepness of 60º or more, snow does not linger at all, i.e. equal to zero. The value of the snow weight in the interval between the indicated slopes is found by interpolation. For example, if the angle of inclination is 45º, then the table indicator should be multiplied by a factor of 0.5, for 50º by 0.33, etc.

How to find wind load

Wind load is needed to calculate the stability of the rafter system. To determine it, we again use a zoning map, but this time compiled from wind pressure values. This indicator is necessary for the rafters of both tiers of the roof, because a gusty wind can tear off and carry away the flat part, and simply overturn the steep part. Information about wind strength determined from the map is corrected by multiplying by a coefficient developed for different types terrain.

In regions with high wind loads, the frequency of attaching rafter legs to the walls increases, i.e. they are fastened with wire twists more often than not. For stability, the number of wind connections increases - struts, supports, boards or slats nailed to three or more rafters. Their weight must be taken into account when calculating total weight roofing structure.

Roof weight load

The weight of the roof is a prefabricated characteristic with individual parameters. Essentially, this is the mass of the roofing pie of a specific insulated or cold design with a certain type of covering and a continuous or sparse lathing specially arranged for the covering. It is calculated per meter of roofing area.

The average weights of coatings can be found on the plate. It should be taken into account that when using embossed roofing materials, the weight of the snow cover should be increased by 10%. For example, if you are making corrugated sheeting with a large wave, you should remember that the snow cover in the recesses can accumulate and lie for a long time.

The weight of the lathing depends on the type of coating. Device soft roof requires continuous flooring made of boards, sheets of moisture-resistant plywood or OSB boards. Profiled sheet metal, slate, clay tiles mounted on bars installed at a certain pitch. The weight of the sheathing will increase due to the installation of diagonal wind ties in regions with high wind loads. The weight of insulation and the rafter system itself with struts, supports, purlins and other elements is also calculated individually.

For preliminary calculations, there are approximate average indicators:

• weight of wooden lathing from 10 to 12 kg/m²;
• weight of layered rafter legs with a run from 5 to 10 kg/m²;
• the weight of the hanging legs of the truss is from 10 to 15 kg/m².

The readings calculated using the programs should not differ too much from the figures given. For insulated attics, the list of loads should be supplemented with the weight of the sheathing. In the case of using insulation with a thermal conductivity coefficient slightly different from 0.04 W/m×°C, its mass can be neglected.

We showed where and how to find values ​​to enter into calculation systems. All other information for the mathematical determination of the cross-section of rafters, beams, and supports is entered according to the design data. If the settlement system warns that “the condition is not met” or is not provided load bearing capacity, the dimensions of the elements should be increased.

Construction of a broken rafter system

Before you begin constructing a rafter system for a future sloping roof, you need to make a project and make calculations of the structural elements. We will assume that the design stage has been completed.

Let's consider one of the typical examples of constructing an attic with two tiers of layered rafters installed above a brick frame. We will attach the rafter system to the mauerlat - a wooden frame made of 150x200mm timber, laid flush with the inner perimeter of the walls. A row of bricks is laid along the outer edge of the box, masking the Mauerlat and removing part of the thrust load. The upper plane of the mauerlat should be 2-3 cm higher than the brick trim.

Installation of floor beams

We begin the construction of the floor by installing the outer beams, the extension of which determines the width eaves overhangs. Next, along a cord stretched between the outer beams, we install intermediate elements with a step equal to the distance between the rafter legs. For insulated roofs, it is recommended to make the pitch equal to the width of the thermal insulation slab, so that the insulation fits tightly in the space between the rafters intended for it. For non-insulated structures, the pitch is calculated so that a whole number of roof trusses with equal distances between them fit.

The size of the timber for the construction of the floor is 100×200mm. When laying beams, we level their upper plane if it is not possible to align them strictly to the horizon. Leveling is carried out by lifting the Mauerlat or placing wood chips under the beam. After attaching the beams to the Mauerlat, we attach a short beam to their end, so that they form a plane for the end eaves overhangs. The spacing between short beams doesn't matter, maybe 1m or so.

Construction of attic walls

We mark on the arranged ceiling the lines for the location of a number of supports for the rafter legs of the lower tier. Along with their supporting function, they play the role of a frame for the walls of the attic.

We proceed as follows:

• We install corner supports, for the manufacture of which we use 100x150mm timber 10cm longer than the final height of the attic ceiling. We check the verticality of the supports with a plumb line; we will fasten them only after we are convinced that the installation is perfect. For stability, we fix their position with temporary braces. By analogy, we install supports in the middle of the gable walls.
• We connect the corner supports with string to indicate the installation location of the intermediate posts. For the manufacture of intermediate supports, a material of 50×150mm with a height equal to the corner supports is suitable.
• On top of two rows of supports we lay purlins made from 50x150mm boards. Temporary spacers will no longer be needed; the constructed walls of the future attic are stable even without them.
• We install a board edgewise on the purlins; it will form the ceiling of the attic.
• We lay a 25x150mm board on top of the ceiling of the attic under construction. It does not need to be installed along the axis of the building. It is better to lay it parallel, 20-30 cm away from the axis.

The result of the efforts made is finished frame attics and supports for installing the upper tier of rafter legs.

Installation of rafters of the lower tier

The rafters of the lower tier of a sloping roof are manufactured and installed using the standard layered method:

• We apply a 25x150mm board of the required length to the end of the structure being constructed and, in fact, mark the lines of the upper and lower cuts with a pencil. This is a template that can be used to make all rafters of the lower tier, if there are no deviations in the geometry of the rafter system.
• If there are doubts about the perfection of the previous work, install only the outer legs and stretch the lace between them. Using the template, we make only the top cut on the remaining rafters. We will mark the bottom line after the fact, aligning the top plane of the workpiece with the cord guide.
• We install the rafter legs. We fasten them to the floor beams with staples or metal corners, and at the top to the purlins with two or three nails.

It happens that to cover the entire length of the lower slope, one board is not enough. In such situations, the rafter is assembled from two short boards, sewn together with a piece of material of a similar cross-section, 1 m or more in length. True, it is still advisable to order lumber of the required length, so as not to weaken the structure with stitched sections.

Installation of rafter legs of the upper slopes

To manufacture and install the upper rafters, you must first mark the central axis. To do this, the inch piece should be nailed to the outermost ceiling board of the attic strictly vertically. One of the trimming edges must exactly match the one indicated in the diagram central axis sloping roof rafter system, further:

• We try on an inch to the end to make a template and mark the cut lines on it, the top of which we draw straight along the axis marked by the cut.
• We make a pair of rafter legs for the upper slopes according to the template. If we have no doubt about the geometry of the constructed frame, we make several blanks at once. Otherwise, we do the same as with our lower brothers.
• We install the first pair of rafters, calling for the assistance of two pairs of working hands. You can’t handle the installation alone, because they don’t have an upper support. To prevent the newly erected roof truss from falling, we support it with a strut.
• We install the remaining trusses of the upper tier. We support them with struts every 3-4 pieces. The angle of inclination of the struts must be more than 45º. The direction of their tilt should be alternated.

Please note that in order to prevent stretching and sagging of the attic ceiling boards, each upper roof truss must be equipped with a board suspension of approximately 25x150mm.

The photo selection will familiarize you with the specifics of the nodal connections of the truss system of a broken-type roof:

Along the ridge line and the break lines of the slopes, the sheathing is made continuous, regardless of the designed type and pitch of its installation. Two boards are nailed across the direction of the rafter legs with a gap of 2-3mm between them. A similar continuous flooring is installed in the valleys, if any, around the roof windows and openings for the passage of the chimney pipe. In the case of using soft types of roofing coverings, the sheathing is arranged continuous over the entire area of ​​the slopes.

If the thickness of the insulation is equal to or greater than the width of the rafters, a counter-lattice is installed in front of the sheathing, constructed by installing a spacer bar. It is necessary to form a gap between the waterproofing and the roofing material. Nail the spacer bar from the outside of the system to the rafter edge. If the thickness of the thermal insulation boards allows you to leave a ventilation gap without remote tricks, there is no need to install a distance bar. It is also not needed in the construction of an uninsulated roof.

Upon completion of the installation of the rafter system, the cornices and gable walls, called gables in wooden house construction, are sheathed. Short overhangs adjacent to the gable walls are built, after which it is time to lay the roofing.

Video selection for self-builders

For those wishing to visualize the process of constructing a sloping roof, three videos with step by step production works:

It is impossible to consider all options for constructing truss structures for sloping roofs in one article. Roofing types, architectural parameters, and regions vary. There are many nuances that apply to specific construction conditions. However, the examples we have given perfectly demonstrate the general technological principle. This information about calculation rules and construction schemes should help both home craftsmen and owners supervising the work of a hired team. Leave your questions, if any, in the comments.

Using all possible space, giving the house originality and significantly reducing heat loss through the roof - these are the tasks that the attic solves. If there is a certain margin of safety at the foundation, in this way you can turn cottage in two-level. Another attractive thing is that you can build an attic roof with your own hands even without special construction skills. It is important not to make a mistake with the choice of materials and do everything according to the rules.

Windows on a regular floor are located in the walls. In attics there are no or almost no walls. They are replaced by a roof. That’s why windows are made special: they not only must let in sufficient light, but also withstand wind and snow loads, which are much greater on the roof than on the walls.

Dormer windows

When planning an attic, you should take into account the recommendations of SNiP. They recommend making the window area no less than 10% of the floor area. So if the attic is divided into several rooms, each should have a window.

Of all the methods shown in the photo for installing skylights with an attic, the easiest to implement is inclined installation. In this case, it is necessary to ensure the proper degree of waterproofing of the junction, and also to use special models with reinforced frames and reinforced glass - the load on the surface can be significant.

Advantages of a sloping roof window:

• more light, less sharp boundaries of light and shadow;
• the roof surface remains flat, its relief is not complicated;
• relatively easy installation.

When planning such a window, it is necessary to remember that its area increases with increasing angle of inclination. At what height is it more convenient to install such a window and how its height increases in centimeters depending on the inclination, look at the photo.

The steeper the slope relative to the floor, the smaller the window height should be.

The width of the window frame should be 4-6 cm less than the pitch between the rafters. Then it can be easily installed without disturbing the structure of the frame. If the window is wider, it is necessary to make a reinforced beam above it and calculate the load.

If you need to have a larger window, it is easier to place two narrow ones side by side. They look no worse than one big one, and there will be fewer problems.

When installing a dormer window, the roof geometry becomes more complicated: a valley appears on top and on the sides. Because of this, the rafter system becomes more complex both during planning and during assembly. The complexity of laying the roof covering also increases. All valleys are the places where leaks are most likely to occur. Therefore, everything needs to be done very carefully. In regions with a lot of snow, it is advisable to install snow guards over such windows so that they are not blown away in the event of a sudden meltdown.

Installation of a vertical dormer window in an attic roof

The advantage of such a window: you can stand near it full height. But they let in less light, the terrain becomes more complex and the roof becomes more problematic.

A recessed window is usually used if there is access to a balcony through it. In other cases, this method of arrangement is not the best option: little light gets in, the shadows turn out to be very deep, which is tiring for the eye, the geometry also becomes more complex, although not to the same extent as in the previous version.

The easiest way is to make a window at the end of the attic. In this case, a reinforced frame or reinforced glass is not needed. Just high-quality glass is quite enough. This option is most often seen on country attics: this is the most inexpensive option, which you can easily implement with your own hands.

Rafter system

When independently building private houses with an attic, they usually choose a broken roof. It allows you to get a room of significant area, larger than under a gable.

With the same width of the base (of the house), the attic space under a sloping roof is larger than under a regular gable roof. The rafter system is becoming more complex, but gable roof with an attic under a sloping roof is still more popular

The design of the sloping mansard roof is such that the overhangs can be lowered quite low, giving the house interesting view. But the long overhang of the roof serves not only a decorative role. They also cover the upper part of the wall from precipitation and divert the bulk of the water away from the foundation. Although when planning you need to keep in mind that in strong winds they increase windage. Because of this, it is necessary to use more powerful boards and beams. Therefore, the size of the roof overhang is chosen based on several considerations, the main one of which is weather conditions.

Tilt angle

Depends on the roofing material, but most of all - on the region and weather conditions. The classic version is shown in the figure: the lower slopes in relation to the plane of the attic floor are inclined by 60°, the upper slopes by 30°. Based on these data and the parameters of your building, you can calculate all lengths. Just take into account that according to SNiP, the ceiling height in the attic cannot be less than 2 m. Then, by definition, this is an attic. A person will feel comfortable if the ceiling is raised to a height of at least 2.2-2.3 m. Based on this, according to the rules of geometry, calculate the required lengths.

At classic version the load from precipitation on the side surfaces may not be taken into account. Precipitation can only be retained on the upper part, the angle of inclination of which is less than 45°.

In general, the inclination of the side surfaces usually varies between 45° and up to 80°. The steeper the slope, the greater the windage it has, this must be taken into account: in regions with strong winds It is better to make flatter roofs. Then wind loads will be perceived much better.

Types of rafter systems for sloping roofs

The design of a sloping mansard roof is one of the options for the rafter system (the most common)

To make the frame of a sloping roof with your own hands, they most often use pine lumber, grade no lower than 2. The choice of cross-section of timber and boards depends on the size of the roof, the selected roofing covering (its weight), wind and snow loads in the region, and the pitch of rafter installation. All these parameters are taken into account in the calculation. The methodology is prescribed in SNiP 2.08.01-89 and TKP 45-5.05-146-2009.

One of the options for constructing a frame with hanging rafters

The figure above shows a drawing of a frame with hanging rafters. It can only be implemented if the base of the upper triangle is no more than 4.5 meters (in this case, this is the width of the attic room). If more, you will have to make layered rafters, which should rest on the load-bearing wall in the middle (the attic will be divided into two parts by a row of beams).

Another version of the upper part is shown in the photo below (the picture is clickable). In this case, the side rafters are reinforced with struts. They significantly increase the rigidity of the system.

There is a second way to achieve a similar effect - to establish contractions - in the figure they are only outlined with barely visible lines. The length of the side rafter leg is divided into three, and contractions are established in these places. They will be needed if the roof covering will have a significant weight.

Option for installing a sloping roof truss system - with struts that increase the rigidity of the system

For a small building, the roof frame can be generally simple: at the top there are two hanging rafters, a tie rod, floor beams, racks and side rafters (pictured below).

Construction of a rafter system for a broken mansard roof for small house

How to calculate a sloping roof

The attic sloping roof of a small house (no more than 6-7 meters wide) has been built so many times that, based on experience, we can say what materials should be used. Many parameters are dependent on other materials. For example, the installation step of the rafters is tied to the parameters of the insulation. To ensure that there is as little waste as possible during insulation and installation is simpler, it is necessary that the distance from one rack to another be slightly less than the width of the insulation (by 20-30 mm). So, if you are going to use mineral wool, its width is 60 cm. Then the racks need to be installed so that the clearance between two adjacent ones is 57-58 cm and no more.

The width of the board for the rafter leg is again determined based on the insulation. For central Russia required thickness basalt wool is 200-250 mm. That's not all. In order for the thermal insulation to dry, a ventilation gap of 20-30 mm is required (without it, condensation will gradually rot the wood and render the mineral wool unusable). In total, it turns out that the minimum width of the rafter leg should be 230 mm. The thickness of the board is at least 50 mm. This is in regions with light winds and not very heavy snowfalls. To summarize, for all rafters - ridge and side - a board of 230 * 50 mm is required.

If lumber with such characteristics turns out to be too expensive, it will be possible to do the insulation in two directions: partly along the rafters, partly, filling the sheathing, across. You can lay a minimum of 100 mm of basalt wool, therefore you can take a standard board 50 * 150 mm and leave a 50 mm ventilation gap, or order a non-standard 130 * 50 mm. It's up to you to see which is more profitable for the money.

For racks and beams, it is better to take a beam of at least 80 * 80 mm, better - 100 * 100 mm. Especially in areas with difficult weather conditions— in case of heavy snowfalls or strong winds.

Order a more accurate calculation from specialists. This is a long process consisting of collecting loads from the roofing material, the structural elements themselves, wind and snow loads. After which a certain formula elements are being selected. More detailed information For information on how the calculation is carried out, see the following video.

Do-it-yourself mansard roof: installation procedure

The design of the Mauerlat on mansard roofs is no different from the standard version. If or logs, you can use the upper crown as a mauerlat. It is only pre-treated with impregnation with high protective properties.

If the wall is made of foam blocks, a reinforced monolithic belt. On brick wall or made of shell rock or other similar materials, the construction of such a belt is not necessary. Waterproofing is laid in two layers on the wall, and on top is a timber treated with an antiseptic - 150 * 150 mm or a log. It is secured with embedded studs.

When assembling all elements, long nails are used - at least 150 mm long. In the most critical places, it is better to connect three or more elements using bolts or studs with double-sided threads. It is advisable to strengthen all joints with steel plates or corners.

First way

Installation of attic roof rafters is done in two ways. First: they assemble the parts on the ground, then lift them up in finished form. There, the outer structures, which will become pediments, are put up first. They are placed vertically and secured. It is often more convenient to secure them with long bars nailed to the wall (temporary). The following assembled structures are inserted into the prepared recesses in the Mauerlat (they are made at the required pitch). They are positioned strictly vertically and carefully secured. If necessary, additional temporary spacers are installed to fix them in the desired position. Side beams are installed.

How to build a sloping roof in this way and assemble the nodes, see the video below.

Second way

The second method - the construction of a sloping roof is carried out sequentially by assembling elements directly on site. This method is more convenient if the structure is large and when assembled it can only be lifted using special equipment(faucet).

First, the floor beams are laid. Stands and ties are attached to them, and temporary spacers are installed to hold them in the vertical direction. Next, the upper and side rafter legs are assembled, and the tie rods and jibs are installed.

During installation, the following sequence of actions is observed: first, install and align desired position extreme elements are securely fastened. If necessary, use temporary spacers. A fishing line, rope, and cord are stretched between them, which will serve as a guide for the installation of all subsequent elements. This simple move allows you to get the ideal geometry (don’t forget to check the slope angle, verticality or horizontality).

On top of the racks, tie-downs are attached - bars, to which the side rafters are then fixed and onto which the tie-down of the upper triangle is installed. The ties are secured using metal corners. Since the beams are long, they sag. This is later eliminated - after installing the upper rafter legs - with the help of vertical beams of fixed or adjustable height. And temporarily they can be supported with racks (so as not to pull the entire system).

To make it easier to maintain the desired angle when installing the side rafter legs, templates are made according to which cuts are made. But since the geometry of buildings built with your own hands is rarely ideal, adjustments may be necessary. To check the resulting angle of inclination, another template is knocked down from several boards, which is used to check the correct installation.

If the standard length of lumber - 6 meters - is not enough, either order the required length (expensive) or increase it. When building up, two boards measuring at least 0.6 meters (30 cm on each side of the joint) are nailed to the joint. They are nailed on both sides or bolts are used.

A reliable way to build rafters. The length of the “patch” is at least 60 cm

After installing the side rafters, all that remains is to install the top ones. A template is also made for them, pre-cut on the ground, and installed on top.

The top part can be made in different ways. Its structure depends on the width of the base. How to make it, look at the photo below.

Since the structure of the attic sloping roof does not provide for the presence of a ridge, a beam is placed in the middle to tighten it, to which the slopes are attached, fixing the triangle in the required position.

Nodes and their drawings

When installing a rafter system, questions may arise regarding the assembly of nodes—the intersections and connections of several structural elements. In the photo you see drawings of key connections.

The second option for connecting the side layered rafters and the upper triangle. Bolts are used for more secure fastening.

How to make a do-it-yourself fastening of the upper tee and rafter leg on an attic roof

Methods for attaching rafter legs to the mauerlat or, as in this case, to the side beam are shown in the figure below. To make it easier to install heavy element, a persistent board (bar) is nailed to the rafter from below, which limits its movement: the board rests against the edge and does not allow it to sink lower.