We are developing a scheme for a single-pitched roof truss system for self-erection. The device of the rafter system of a pitched roof Hanging rafters of a pitched roof

The shed roof rafter system is a simple structure. It attracts with its reliability and economical material consumption. The erection of a pitched roof is permissible on our own and is carried out in a short time.

It is popular for garages, outbuildings and sheds. Residential buildings are less often covered with a roof with one slope, but such options are found in the embodiment of the original architectural ideas of building a building. With all the simplicity of the structure, work on the creation of the roof is a very crucial stage and requires adherence to technology.

The scheme of the rafter system for a small building is quite simple: inclined rafters, laid on the Mauerlat, overlap the distance between the end walls. The span of the building in this case is no more than 4.5 m. The slope of the slope forms the difference in the height of the opposite walls. It can be provided in two ways:

install on one of the walls special supports under the upper edges of the rafters;
when maintaining the masonry of supporting structures, one should be performed above the other.
When orienting the slope, the low part of the roof is directed towards the constant winds, this will ensure the stability of the frame to high loads.

The function of the rafter frame is to redistribute the constant and emerging loads on the roof between the load-bearing walls. Its constituent elements are:

mauerlat - a bar at the base of the structure, connecting it to the walls of the structure;
rafters - a board or timber that forms the basis of the frame;
struts, racks, benches - elements that reinforce the structure with a span of 6 to 9 m;
lathing - slats, stuffed at a certain technology distance, are the basis for the roofing and strengthen the rafter system.

A single-pitched design has less windage than systems with a large number of slopes, but when designing it, the weight of the snow cover must be taken into account. This is especially true for roofs with a small slope angle of 8-10 degrees. When creating drawings, the location and size of all elements of the rafter system, as well as the installation diagrams of the frame nodes, are noted.

The distance between the rafters of a pitched roof is recommended in the range of 60-80 cm, this allows you to ensure sufficient strength for any coating used. The presence of overhangs 25-40 cm long on each side of the building guarantees the drainage of rainwater from its walls, excluding their erosion.

Advantages of a pitched roof

Lumber consumption is significantly reduced compared to more complex structures.
The cost of construction is reduced.
A wide range of roofing materials as a topcoat.
Installation of the rafter system can be done independently, within a short time.

How is the angle of inclination determined?

The slope of the slope is one of the main parameters of the roof. The intensity of the load on the rafters directly depends on this indicator. The main selection criteria:

The amount of precipitation in the region.
Roofing type.

A large angle promotes unimpeded snow melting, but leads to additional material consumption. A slight slope reduces wind exposure, but requires frequent snow removal from the roof. The optimal angle is also associated with the type of roofing; for each material there is a recommended parameter in degrees:

metal tile - 25;
slate, ondulin - 20;
roofing material and other roll materials - from 5 to 10;
corrugated board - 20;
natural tiles - 35.

Preparation of lumber before installation

The operating time and reliability of the roof depends on the quality of the lumber used in the construction of the frame. The use of dry coniferous timber is recommended. The wood must be free from knots and damage. Before installation, it undergoes mandatory treatment with an antiseptic and fire retardant, these compounds protect against decay and fire. The size of the bar depends on several factors:

span length;
the amount of load on the roof (snow, wind, etc.);
slope angle.

The cross-section of boards for rafters is 50 × 150 mm, 60 × 180 mm, a bar for a Mauerlat is 150 × 150 mm, for a lathing is 50 × 50 mm.

Stages of installing the rafter system

The construction of the frame begins with the installation of the Mauerlat. Before installation on the walls, the timber is wrapped with roofing material for waterproofing. The base is fastened to the studs laid down during the laying or with the help of anchor bolts.

Installation of rafters is carried out on a fixed Mauerlat. For a solid fixation, it is necessary to make cuts on the boards. To ensure that all inserts have the same size, they are made according to a template. The upper part is cut with a bevel, which allows the rafters to bend. The bottom notch serves as a solid support for the Mauerlat.

The roof rafters are fastened with nails and corners screwed on with self-tapping screws. It is possible to simplify the installation of the frame by installing the extreme rafters and stretching a rope between them, which defines the plane.

With a run length of more than 4.5 m, a brace is installed at an angle of 45 degrees, one edge of it rests against the rafter, and the second against the Mauerlat.

The end of the installation will be the stuffing of the crate. Its bars are located perpendicular to the frame, the fastening step depends on the finish coating. A continuous crate is made for rolled material. For covering, moisture-resistant plywood or OSB boards are used.
After installing the rafter system, a waterproofing sheet is laid and the roof is insulated. The final stage of work is the installation of the roof covering.

A pitched roof is not so often used for arranging the roof of private houses, although the structure itself and its installation are much simpler than a gable. It is believed that this type of roof does not retain heat well enough in the house, therefore, it is more often used in the construction of country houses and sheds. However, it should be noted that it is quite possible to make this structure warm and even arrange an additional room under it, if the thermal insulation is installed correctly.

A do-it-yourself gable roof is made according to preliminary drawings made on the basis of the calculations performed. This is especially important in cases where it is planned to make a living space under it.

The main advantages and disadvantages of the design

The advantages of this design include the following:

Saving money on the purchase of building materials.
Simplicity of construction, and hence of installation.
Low weight, compared to the gable version - less load is placed on the walls.
High resistance to wind and load from snow accumulated on the roof.
The structure can be erected in a different angular range - from 5 to 45º.
The sloping roof, made at a slight angle, allows you to install a hot water tank or solar panels on it, as well as arrange a place for rest.
Such a structure can be covered with any of the existing roofing materials, of course, taking into account the conditions of its operation and the angle of inclination.

Naturally, like any design, a pitched roof has its drawbacks, which you also need to know when choosing this option:

A roof with one slope requires more serious insulation than, since there is not so much space under it that creates an air gap. Without the provision of reliable thermal insulation in the summer months, the attic space will be very hot, and in the winter months it will cool down, and in either case it will transfer the temperature to the house. However, if you correctly calculate and install all the elements, then this disadvantage can be avoided.
If the overlap is done immediately under the roof, arranged at a small angle, then the house loses not only the upper air layer, but also the attic, which means that the opportunity to arrange an additional room - this can be considered the second design flaw. But, if the attic space is planned a little differently, then this disadvantage can also be dealt with.

Another drawback of a single-pitched roof refers only to a structure with a slight slope of 5-10º - it is a poor descent of snow masses from it. So, in case of a large accumulation of snow, the roof will have to be cleaned manually or a heated roof system should be made using a heating cable.

Prices for heating cables and accessories

Heating cable and accessories

Video: a small country house with a pitched roof

Calculation of the structure of a pitched roof

If a decision is made to arrange a pitched roof, then first you need to make the calculations and make sure they are correct, having personally seen the preliminary result on the drawing. Only in this case can you get exactly the option that is ideal for a particular building and its residents.

In order to draw up such a scheme, you will need to determine the following parameters:

The total width of the structure and the length of the spans between the load-bearing walls.
The estimated angle of inclination of the ramp.
The total length of the roof.
Desired roofing material.
The height and width of the load-bearing walls.

If the roof is planned for a country house or, then it is enough to make the front wall of the building slightly higher than the rear one to a certain height in order to deduce the angle of the slope.

- The internal distance between the walls will determine how much the rafters should be strengthened and how many beams are required.

- Before executing the drawing, it is necessary to decide whether it is planned to arrange a living room in the attic room - the angle of inclination of the slope and the height of the gable to be erected will depend on this decision.

- Also, the angle will depend on how much you plan to make the trump card To to the lynx in front and behind the structure.

- In addition, you need to decide on the location of the veranda or terrace, since the roof can cover it in front or behind the house.

- The above factors directly affect the length, and the total length of the building - on their number.

- The rafters are laid across the structure at a distance of 500 to 800 mm from each other. The wider the building, the longer and more massive the rafters should be. Their cross-section varies from 80 × 150 mm and above. For example, if the rafters are fixed over a span of 6-7 meters, then the size in the cross-section of the rafters should be at least 110 × 200 mm.

- For the manufacture of rafters, high-quality, well-dried lumber is selected that does not have cracks and large knots, especially in the areas of their connection with other parts. made from thick boards or timber.

- When the length of the workpieces is not enough due to the large width of the structure, they have to be joined. The connection of two parts of the rafters into a single piece is recommended to be placed on the support beams or, if they consist of boards, one of them should be at least 500 mm on top of the other.

- Sometimes the rafters are even made up of three parts. In this case, the central part of the rafter extends to the extreme ones also at a distance of 500 mm.

- So that over time the rafters do not sag, they are propped up and fixed with various elements of the rafter system - struts, crossbars and racks. Such additional details are used if the span width exceeds a distance of 5 meters.

The cross-sectional dimensions of these reinforcing elements should be at least 50 × 100 mm, and for gaskets and beds — 100 × 150 mm.

- With a span of 12 m, a stand must be installed in the middle of the floor beam, which also serves to support the rafter leg.

- If the length between the opposite walls exceeds 12 m, then, in addition to the rack, additional rafter legs are installed - they will give rigidity to the flooring.

- With a distance between the load-bearing walls of 15 meters or more, there should be at least two racks, and each of the rafter legs is installed as close as possible to the middle of the rafter span between the gable wall and stanchion... Additionally, in the center of the structure, the racks are fastened together with a scraper bar - this distance should be one third of the width of the structure.

- At whatever angle the pitched roof is arranged, the rafters are laid on, fixed on the walls and on the pediment.

The diagrams show options for supports in rafter systems, with spans of different sizes between the walls. You can easily navigate by them, drawing up a project diagram for a specific building.

The roof drawing should contain all the necessary information about all the dimensions of the structural elements and the distances between them. Having such a scheme at hand, it will be easy for it do work, therefore, the drawing must be made very carefully and accurately.

Calculation of the angle of the roof slope

It is calculated based on the fact that the roof has the shape of a triangle, with one corner always right. This angle is formed by the legs of the floor beams and the pediment part of the structure, and the rafters in this figure play the role of the hypotenuse.

In the figure shown, the following conventions are used:

— Lc- the length of the rafter leg;

— Lbc- the height of the gable from the floor beams to the intersection with the roof plane;

— Lsd- the width of the house;

— A- the selected or calculated angle of inclination of the slope.

If you recall the basic school course of gas metering and arm yourself with a calculator, then it will not be difficult to calculate all the parameters of the future roof based on the initial values. The width of the building is easy to measure, and either the desired gable height or the selected roof slope angle can act as the second parameter.

So, if the width of the building and the planned height of the pediment are taken as a basis, then the slope angle is easy to calculate with the formula:

TgA = Lbc: Lсд

If the selected angle of the roof slope is taken as the basis for calculations, then the height of the pediment will be equal to:

Lbc =TgA× Lsd

Lc = Lsd: СosA

At the same time, do not forget that the length of the rafter, calculated in this way, is only up to the intersection with the plane of the walls, excluding the canopies on the front and back of the building.

The slope of the slope angle is selected depending on some criteria, one of which is the selected type of roofing material, since for each of them it is recommended to choose a certain value or parameter as close as possible to it, for example:

- Decking requires a slope of at least 8º.

- When changing metal tiles, you can make a roof with a slope of 30º.

- For slate, an angle of 20-30 ° is well suited.

- For rolled roofing materials, such as roofing felt, as well as other soft roofs, a slope angle of 5-7 ° is recommended, but not less.

If the roof does not have a heating system, and the building is located in a region where there is a lot of precipitation in winter, then a shed roof, arranged at an angle of 40-45 °, would be the best option, no matter what kind of roofing material it is covered with.

In addition to the above data, you need to understand what types of rafter systems are.

Types of rafter systems on a pitched roof

When arranging a pitched roof, it can be performed in one of three options, the choice of which depends on the type and size of the structure:

The hanging system is installed in rare cases when there are no capital partitions between the main load-bearing walls. When building such a roof, for the convenience of work, a temporary flooring of boards is laid on the floor beams. On this basis, the trusses of the truss system are assembled. In order for the hanging system to be reliable, the parallel walls on which the floor beams will be laid must be brought out to the same height. If necessary, this type of construction is used in houses built from any types of materials used in construction.

If a room is planned in the attic, then ventilation is arranged as for a living room.

If the structure will only play the role of an attic, then ventilation should be strengthened, since the room will not be heated. Ventilation in this case should function effectively so that moisture does not accumulate here and dampness and mold do not appear, which will eventually appear in the house.

Roof rafter systems are distinguished by the fact that they are installed in buildings with internal capital partitions, which become additional supports for floor beams.

In layered systems, the rafters are rigidly installed on the gable wall, on which in advance installed mauerlat, and their lower edge can be fixed both rigid and sliding mounts. Such structures of a pitched roof are mainly used to cover brick or stone houses.

For the rigidity of the structure, additional spacers are installed. There are several systems for their installation, depending on how much free space should be in the attic, the slope angle of the slope and the massiveness of the rafters.

The sliding rafter system is mainly used for log cabins, as it avoids deformation of the roof structure if the house shrinks. When installing this type of roof, the rafters are rigidly fixed on the pediment wall, on the Mauerlat, and their lower part is attached to the Mauerlat exclusively with sliding fasteners, which, when the walls of the house vibrate, allow the rafters to take a comfortable position.

Shed roof installation

Having specified v all the necessary nuances, making calculations, drawing up a roof drawing and purchasing in required for work materials, you can proceed with the installation of the structure.

To make the work easier and safer, the building must be immediately covered with attic beams. They are laid on strips of roofing material waterproofing, laid on the walls. The beams are placed at the same distance from each other as the rafters will be installed in the future - it usually ranges from 500 to 800 mm.

Timber prices

On the rear lower wall of the building, along its entire length, on top of the floor beams, a Mauerlat is laid from a massive bar.
Further, a flooring of boards should be laid on the beams - it will be safe to walk on it and it will be more convenient to continue the construction of the structure.

The next stage is the erection of the pediment wall, it is built from the same material as the entire building, or from another, lighter one. For example, if the building is made of bricks, then the pediment can be raised from bars and planks.
Floor beams, previously closed with waterproofing, are embedded in the wall. The pediment is raised to the height provided in the drawing.
On the pediment wall, as well as on the opposite one, the Mauerlat timber is fixed.
Further, markings are made on the lower wall, and fasteners are screwed on for installing the rafters.
On the rafters, for their rigid attachment, according to the drawing, grooves are cut with which they will be put on on mauerlat on the top wall and the bottom, if provided.

Then they are fixed with special corners and fasteners. On the pediment, the rafters are screwed tightly, while on the lower Mauerlat they can be installed in sliding mounts, depending on the type of construction chosen.

There is a sequence of cutting the rafters: first, the extreme elements of the entire rafter system are installed, then a cord is pulled over them, which will become the level for the rest of the parts. Distance betweenrafters must comply distance between floor beams.
The installed rafters for stability are connected to the floor beams with racks, struts and other elements, which were discussed above. They are fastened with metal brackets and corners, which adds rigidity to the structure.

If it is necessary to lengthen the rafters beyond the level of the walls, "fillets" are mounted to them

If it was supposed to extend the roof for the device of the terrace, or veranda, then additional boards, which are called "filly", are additionally attached to the rafters.

Video: the process of building a layered shed roof

Prices for various types of fasteners for rafters

Fasteners for rafters

After completing the installation of the rafter system, it is necessary to move on to insulation measures, since a pitched roof especially needs thermal insulation, even if an ordinary attic is located under the roof.

Suitable for this , descriptions of which can be found on our website by clicking on the link.

The lathing device for the roof or the continuous sheathing of the roof is carried out taking into account the selected roofing material - each of them has its own technology for such work.

Video: solid cladding of a single-pitched garage roof with boards

The device of any roof is a responsible and time-consuming process, and because of work at height it is also quite dangerous. Therefore, without experience in the construction craft, it is better to entrust the installation to masters who know their business, since an unsuccessfully built base for the roof threatens that the walls of the house will also be subject to deformation.

6 main types of rafter systems

	Name	Rating
#1		⭐ 100 / 100
#2	Tent rafter system	⭐ 100 / 100
#3		⭐ 100 / 100
#4		⭐ 99 / 100
#5		⭐ 99 / 100
#6		⭐ 98 / 100

Gable rafter systems are the most popular for single-story private houses. They look neat, fit well into any style of construction, are reliable and can be used, depending on the angle of their slope, to equip an attic for living rooms, utility rooms, or simply to create an air gap that keeps heat in a building.

high reliability;
simplicity of design;
a gable roof with an angle of inclination of more than 50 degrees is practically not afraid of snow drifts, a large snow cap will not form on it.

for buildings with a hipped roof, gables are not provided, which greatly reduces the consumption of materials and work for the construction of gables and filing of overhangs;
a roof of this type has excellent aerodynamic properties, strong winds are not afraid of it, and the design features will not allow precipitation to fall into the attic;
the surface of such a roof is warmed up by the sun's rays from several sides at once; on sunny days, the room under an uninsulated roof will be warmer;
the slopes of such a roof are located at a certain angle, which helps to drain rainwater and melting snow from the roof.

hipped roof is quite difficult to design and build;
the structure of this roof is replete with a large number of joints, beams and rafters, it is necessary to strictly monitor the reliability of all nodes and joints, in order to avoid loss of rigidity and plane shape when erecting a roof;
large waste when using most roofing coatings (especially metal tiles).

Lomanes are called attic rafter systems, which are used in cases where it is planned to equip a living space in the attic space, since this structure forms the most spacious area of future rooms. Each of the two slopes of the broken rafter system consists of two planes - top and side.

additional living quarters;
an attic is cheaper than building a full-fledged second floor or expanding the perimeter of housing;
the appearance of a private house with a sloping roof is superior to that of a classic gable roof.

the inability to create a spacious room in the attic, because the height of the walls is limited by the roof;
heat and waterproofing will be carried out using more complex techniques and using special materials;
Skylights increase the requirements for roofing and accumulate more snow on them.

The multi-slope rafter system can be called the most complex of all existing ones, since it often includes different forms of roofs - it can be gable and single-slope, hip-roof, hip or half-hip in various combinations. This option is chosen for houses with a complex internal layout, and in recent years there are more and more of them.

reliable, durable and solid construction;
due to the large slope of the roof, the risk of stagnant melt water and precipitation is reduced to zero;
fits perfectly with any architectural form;
the presence of a balanced rafter system.

the complexity of the installation work;
the device of a large number of valleys;
high consumption of building and roofing materials;
complex care and maintenance of the structure.

Hip roofs have four slopes, with the pediment sides having a triangular flat shape, and the side slopes of the structure - trapezoidal. It is the triangular slope that is called the hip - it joins the trapezoidal plane at a certain angle.

does not undergo deformation;
snow does not linger;
will perfectly withstand strong winds, for regions where hurricanes and tornadoes are not uncommon - a big plus;
places of eaves overhangs are less exposed to destruction.

differs in a higher cost than gable;
the design turns out to be complex, usually the construction of a hip roof is trusted by specialists, and this is again additional costs;
equipping an attic under a hip roof is a difficult task, often simply insoluble.

As the name implies, this roof has one slope. If the building is small in size and is completely built of brick or concrete, then the rafters of the structure are laid on the front load-bearing high and on the rear low wall. If the distance between the facade of the building and the rear wall is six or more meters, then retaining posts are installed between the front and rear walls.

profitability (almost double the savings in sawn and roofing materials compared to a gable roof);
low weight of the roof (makes it possible to erect it on buildings with a lightweight foundation without the use of lifting equipment);
the possibility of arranging a pitched roof on large houses;
maintainability (ease of movement on the roof, especially at small angles of inclination);

high dependence on snow loads (requires correct calculations of sections of structural elements during design);
reinforced heat and waterproofing of the roof (important for small angles of inclination);
unsightly appearance, which requires increased attention to the quality of facade work and the use of modern roofing materials.

Unlike the gable version, the gable roof is used in the construction of residential buildings much less often, one might even say reluctantly. First of all, because of the external angularity and excessive simplicity. A residential building under such a roof does not look very attractive. An exception may be the author's design projects for cottages with several multi-level single-pitched roofs, they look very beautiful, but they are quite complex and require considerable effort in practical implementation.

What is the peculiarity of a pitched roof

Such a system is simpler and more affordable to make with your own hands, it is quite simple to assemble it for a garage or warehouse. Often, a pitched roof is the simplest and most effective solution for arranging simple auxiliary or utility rooms, for example, for making a roof on a brick extension to a house.

The advantages of a gable roof include the following positions:

The weight from the rafters and power trusses in the roof frame does not create bursting forces, as is the case with gable options;
The rafters of a single-pitched roof, even with a large roof span, do not require the use of a massive and thick beam, as for more complex two and four-pitched options. The main part of the load is transferred by the rafter system to the floor beams and walls of the building using struts, racks or load-bearing support trusses made of a conventional 50th plank;
The use of a pitched roof often becomes the only possible option if you need to add an extension to the main wall of the house, as in the photo, or even make a roof over the balcony.

For your information! In some cases, problems associated with asymmetry and significant side load on the roof caused by strong winds from the high gable can be avoided. To do this, it is enough to install a small, 60-70 cm inclined canopy on the leeward side.

Due to the minimum requirements for the quality and size of lumber, from which the shed roof rafter system is built, the simple installation of rafters and a roofing package, this method of arranging the roof is almost indispensable for the construction of any auxiliary buildings.

Features of the use of a pitched roof

In addition to the listed advantages and simplicity of the device, the single-pitched rafter system has its own specifics, which should be taken into account when planning the roof parameters:

Advice! The most preferable way of arranging a pitched roof would be the option of an extension to the main wall of the finished building.

Shed roof rafters

There are three main ways to install roof rafters. According to the configuration of the construction of the rafters, they have a lot in common, the main difference lies in the way of compensating for the vertical loads on the rafter.

Installation of a rafter system from short beams

With a span not exceeding 4.5 m, the rafters can be made from a bar or board with a section of 50x100 mm and installed with support on the upper and lower row of the Mauerlat. If the Mauerlat is laid in a niche below the upper edge of the wall, then the upper edge of the rafters is cut vertically, and the support surface of the board is cut with an angle to support it on the Mauerlat bar. In this case, the joint between the end of the rafter and the wall surface must be closed with an overhead cornice element.

If the rafter rests on the Mauerlat, laid on the upper plane of the wall, in this case the edge of the rafter beam is also sawn under the support on the timber, but the vertical cut of the end is made under the plane of the wall. After leveling the roof rafters, the vertical plane of the cut is closed with a film and sewn up with a board. In both cases, the rafter beams are sewn with staples or steel tape directly to the Mauerlat board.

The lower edge of the rafter can be installed with an emphasis on the masonry of the wall. To equip the overhang, "filly" can be sewn to the rafters, and the beam itself is abutted against the corner of the Mauerlat and fixed with a wire loop on the inner surface of the walls or ceiling board. Usually, this option is used for roofing made of corrugated board or bituminous tiles, as in the figure.

Roof device made of long rafters

A more complex option for assembling a shed roof is a system with a long span. With a ceiling length of up to 6 meters, it is enough to support the rafter beams with additional supports. The rafter leg is attached to the rafter board with a steel plate and self-tapping screws without a tie-in.

For spans longer than six meters, at least one intermediate support is required on the inner wall or a reinforced beam in the ceiling. With a large span, there may be two or three intermediate posts. In this case, in the transverse direction to the roof slope under the rafters, an additional run beam is laid, leveling the roof plane. Each run is installed on a vertical stand and reinforced with rafter legs and grappling.

Installation of a simple truss system on transverse truss frames

The most common scheme for constructing a frame from prefabricated rafters is the option with the support of rafter beams on prefabricated trusses. In previous versions, the installation and fastening of the shed roof rafters was carried out on the basis of two walls of different heights. This gave certain advantages. Due to the high rigidity and strength of the brick walls, there were no problems associated with the occurrence of shear lateral forces when arranging the roof; therefore, the shed roof structure was configured only for vertical loads.

In practice, such ideal conditions arise only when an extension is made to a finished brick wall of a capital building. Much more often it is required to assemble a pitched roof on a brick or cinder block box of a garage or bath with the same height of all walls. In this case, the roof rafter system will be more vulnerable to shear force from wind load.

In this version, for the assembly of the roof frame, layered rafter beams are used, laid on two prefabricated trusses or frames. One of them is combined with the main pediment of the building, the second truss is installed in the middle, on the main inner wall of the building. The entire roof structure is installed on a 50 mm board laid with a harness that acts as a Mauerlat. The board is attached to the brick of the wall with wire, steel tape and fence dowels. The result is a strong and flexible enough mount.

First, a first support frame is made. The first truss is assembled from vertical racks fixed to the base of the Mauerlat with spacer metal corners. This is the most laborious and crucial moment of work, it is required to align the upper support bar of the frame strictly horizontally, it depends on how smooth the roof slope will turn out.

Before proceeding with the assembly of the second frame, it is necessary to assemble two reference rafter beams on the ground. As usual, long rafters are made by splicing two short ones with padding over the halves of a third piece. Both rafters are laid out along the edges, with one end on the first truss, with the other end on the Mauerlat board from the opposite side, and carefully adjust the angle of inclination of both rafters.

Further, focusing on the height of the installed reference rafters, a second support frame-frame is assembled, located in the central part of the box. At the next stage, the pediment of the first frame is sewn up with a board, spacer beams and wind boards are installed, as in the photo. This will ensure high rigidity of both frames, even in strong frontal winds. This is the specificity of creating a roof on frames of increased rigidity.

The rafters are attached to the harness board with steel brackets and wire loops. If desired, you can use a bolted connection as a fastener for the rafter system. One of the advantages of layered rafters is that they can be easily spliced using two shorter planks. Most often, the two parts of the rafter are laid on the supporting truss-frames, after which the two halves are simply knocked together with nails. Each of the rafters is carefully aligned at two points - the middle support frame and the lowest point of support on the harness. Next, it remains to hammer in 100 mm nails, the laid and adjusted rafter beams.

Before performing the lathing, the side gables of the roof are sewn up with a board. This gives the entire structure the necessary rigidity and strength. Some of the rafters are made in the form of lower and upper overhangs. The end surfaces of the rafter boards are knocked out with a cornice board and the lower part of the cornice is sewn up with clapboard. At the next stage, it is necessary to tie the rafters with sheathing boards, they are laid on the beams and nailed in a checkerboard pattern. It remains to lay the ceiling and roofing material.

Various assembly options for mounting rafters on a pitched roof

In addition to the above variant of assembling the frame for a pitched roof, in practice, simpler and more affordable ways of attaching the rafter system are often used.

For example, when assembling a garden house from a bar, it is enough to simply lay the rafter beams with a certain pitch on the pediment and the upper beam of the back wall of the house. In this case, the rafters, in addition to the supporting structure for the roof, play the role of a stiffening element for the whole house.

It is quite simple to assemble a shed roof structure for a wooden extension to a house from a bar. The upper edge of the slope is installed on a beam, which rests on vertical posts nailed to the wall of the house. It can be seen from the photo that the lower support beam for the roof rafters is installed on vertical posts, the whole structure is made in the form of a frame with additional frontal stiffeners. Each of the rafters has a cut under the supporting surface of the bearing beams.

In some cases, for example, when attaching a garage to a main wall, you can use the ends of the ceiling beams to fasten the rafters, as in the photo. In this case, the rafter is rigidly attached with a pair of steel corners to the protruding end part of the beam.

The alluring simplicity of a single slope roof inspires thoughts of the opportunity to prove themselves in the field of a successful builder. The construction of an unpretentious structure consists in the banal laying of rafter legs on the supporting walls. No complicated knots, tricky and numerous joints. However, even in the simplest carpentry business, there are tricks that require thorough study. The future performer needs to know firmly how the shed roofs are fastened in order to exclude deformation and damage to the elements of the frame system.

Traditional "wooden" troubles

The scheme of the rafter frame of a pitched roof is simple to the limit. It is a row of parallel-laid planks or beams resting on the edges on two walls of different heights. To install and fasten the rafter legs to the building structure, a transitional element made of wood is used.

Depending on the type of the equipped box and the material of the walls, the function of the transition element is performed by:

Mauerlat. In a pitched roof scheme, these are two separately laid wooden beams, completing concrete or brick walls.
Upper piping of the frame structure. A belt of double stitched planks or beams installed on top of the frame racks.
The upper crown of the foot, folded from a bar or log.

The rafter legs and the elements in contact with them are made of wood, which has the property of changing its own dimensions following fluctuations in the humidity background and temperature drops. In spring and autumn, especially during the rainy period, the length of the rafter legs will be slightly longer than in dry summers and frosty winters.

Imagine what would happen if the rafter rigidly fixed at the top and bottom increases in size. There will be gaps in the waterproofing, the fasteners will loosen, the slate sheets will move, the metal tile will move. In addition, the deflection and swelling of the roof frame will certainly affect its wear resistance.

However, changes in the linear dimensions of the rafters are not at all the main hitch of wooden rafter systems. An unpleasant surprise, if not taken into account, will be the draft of the newly built box.

It manifests itself most vividly near wooden walls, but structures made of concrete and brick are also very characteristic. Recall that pitched roofs rest on walls of different heights. Without calculations, you can understand that they will sag by different amounts. Those. there is a threat that, due to the difference in the subsidence of the walls, the new roof will not just change the slope angle. There will be a possibility of a violation of the nodes with extremely negative destructive consequences.

Despite the simplicity of pitched roofs and the direction of laying the rafters close to the horizontal, the listed risks should not be forgotten. The nodes used in fastening the rafter legs of a pitched roof must take into account the "whims" of the wood.

The work of the developer of his own project of a shed roof is to find the right solution to three important tasks, according to which:

It must be possible to move the wooden parts relative to each other.
All probable causes of poor connections should be ruled out.
It is necessary to provide the rafters with the opportunity to adapt to the consequences of wall subsidence so that they can take a stable position.

The rafter legs of single-pitched roofs erected above walls of equal height are classified as layered. The hanging type is used if the box being equipped has walls of equal height and the ramp is formed by rafter triangles.

With the fastening of triangles, everything is clear: with the horizontal side they are installed on a strapping or Mauerlat, have a maximum docking area with supporting elements, and are fixed in the usual way.

With layered rafter legs, everything is much more complicated. They are installed at an angle to the supporting elements. Without processing and preparation for installation, the rafters have only two unreliable points of contact with the strapping or Mauerlat.

No matter how powerful the fastener is, two points are not enough for a solid fit of the part. Even with a slight impact, such a slope will simply slide down along with a solid crate and a multi-layer roofing cake. However, there are methods invented by ancient builders to avoid such troubles.

In order to prevent unwanted movements, the contact area of the rafters and the supporting element is increased; for this, the following is performed:

Selection of cuttings. These are cuts in the shape of a triangle or a triangle with a tooth. Saw them exclusively on the rafters, so as not to weaken the bearing Mauerlat.
Washed down the upper or lower edge of the rafter leg, thereby creating a support platform that increases stability. It is performed strictly vertically or horizontally.

Depending on the type and place of sawing or trimming, cuts and saws can limit or not restrict the movement of a wooden part. The restrictions are considered relative, because there are no absolutely rigid fastenings in the construction of pitched roofs. Experts classify the knots used according to the degrees of freedom: from one to four.

In the construction of roofs with one slope, most often appear:

One-degree-of-freedom attachments are virtually fixed joints that allow the rafter to pivot slightly around the attachment point.
Attachment nodes with two degrees of freedom - connections that provide the ability to rotate around the fastener and slight horizontal displacement.
Three DOFs are connections that allow horizontal and vertical rotation and displacement.

The presence of degrees of freedom does not at all mean that the rafter can freely rotate and move in the area of the node. They are fastened quite rigidly, because they have to hold the crate, corrugated board or other type of covering, snow cover.

The connection will show its own capabilities only if the load is exceeded. Then the rafter legs will just move and take a new position, and the system will remain intact.

Any scheme of a shed roof visually depicts the presence of at least two connecting nodes. Let's divide them conditionally into upper and lower ones. In the construction of truss roofs, the rule applies: if one of the nodes is fixed rigidly, then the second should have more opportunities for movement.

Projecting and simplifying the technological principle, we can say: if the fastenings in the upper nodes of the pitched roof are made rigidly, then the lower connections should be more free in order to ensure the possibility of displacement when pressure is exceeded. And vice versa: if the lower mount is practically motionless, then at the top of the rafter you need to provide some kind of reserve for movement and rotation.

Details about the nodes of the pitched roof

After getting acquainted with the theoretical side of the question of fastening the rafters of a pitched roof, you can proceed to practical research of the demanded nodal schemes. Note that most projects of systems with a single slope are designed for the installation of rafters that form overhangs due to their own length. However, when overlapping large spans, it happens that there is not enough standard lumber dimensions. In these cases, filly are sewn to the rafters, creating an overhang. They are installed on the side of the installed leg and do not affect the principle of forming a knot at all.

The second reason for using fillies in the formation of overhangs is too weighty rafters, which are very difficult to lift and install. The third prerequisite lies in the peculiarities of the nodal bindings: if the lower heel is installed on a slider with a cut-off edge.

No. 1: Support at the top and hinge-movable bottom

A scheme with a rigidly fixed top and a relatively movable bottom is used in the construction of roofs over extensions, in the construction of objects with a steep roof and a significant difference between the heights of the supporting walls.

Simply put, where the upper edge of the rafter rests against a wooden beam, the purlin or wall of the main building is not left with space for movement. The lower knot in such situations is calculated on a slider, which allows it to move slightly.

Algorithm for the classic version with the top resting on the girder:

We install the purlin frame supports. On the strapping of the frame building from opposite sides, we install supports sewn from three pieces of board 25 × 100. The middle segment should be 75mm shorter than the outer ones in order to form a kind of notch.
We build a purlin frame. We put a board 25 × 150 of the required length into the recess.
We apply a 25 × 100 board of arbitrary length to the end of the future roof, but more than the diagonal drawn from the top of the running frame to the strapping, by about 30 cm. Mark the vertical line of the upper cut, outlining the adjacent edge of the run. We mark the line of the bottom cut and the vertical for trimming the edge of the rafter.
We cut out the rafter according to the marks, try it on in fact, correct the cuts if necessary.
According to the made template, we cut out and mount the rafter legs.

We select the type of fastener based on the expected load. It is more convenient to fix the top with corners, the bottom - with corners, twisting no more than three self-tapping screws in them, or sliding supports. If necessary, the lower knot can be stabilized - sew a support block to the rafter leg from below.

The junction with the purlin can be designed a little differently: the rafters are laid on the beam using a cut. Here the groove is selected strictly according to the size of the material. But if it is necessary to increase the degree of freedom, the horizontal wall of the cut is beveled at an insignificant angle, and the lower unit is equipped with a sewing bar.

No. 2: Top and bottom hinge-fixed

The scheme is applicable when arranging boxes, the walls of which have already undergone intensive shrinkage. Suitable for detached objects. The upper knot is made in the form of a triangular cut, the lower one is in the form of a gash with a tooth resting on the Mauerlat.

The construction process of a shed rafter system:

We install the blank board with an edge on the Mauerlat beams anywhere on the roof.
Lay a well-cut piece of board flat on the lower Mauerlat. We put it so that the extreme edge coincides with the inner edge of the Mauerlat. Having outlined the trim, we get the outline of the lower attachment point.
We transfer the cut to the area of the upper cut and outline it, because the lower heel of the rafter will decrease by this amount.
A workpiece with knots drawn and then sawn out will serve as a template. Using it, we make the number of legs specified by the project.
We install the rafters. We fix it at the bottom with staples or pins, at the top with corners.

If it is necessary to increase the degree of freedom, by analogy with the previous method, the vertical edge of the upper cut will need to be slightly beveled. The angle of the cut will then turn out to be not 90º, but 95 - 97º. Experienced carpenters make simple cuts directly on site, turning the workpiece upside down. Beginner performers should not be imitated in the early stages.

The rafter pattern is used in roof construction only when there is no doubt about the geometric characteristics of the box. In the opposite situations, the rafters are tried on and made piece by piece. First, the extreme elements of the system are installed, then ordinary legs along the lace stretched between them.

One of the variations on the theme of two hinge-fixed nodes involves the device of a vertical gash at the top and notches with a tooth at the bottom. Work on their arrangement is carried out as follows:

We install the blank board on the Mauerlat so that its lower corner is directly above the outer edge of the timber.
At the top, using a piece of board, mark the vertical line of the cut (x) and measure its length.
We transfer the length of the upper cut to the area of the lower node. We set aside the length of the cut (x) upward vertically from the inner upper edge of the Mauerlat.
Draw a horizontal line from the resulting point. The result is a notch with a tooth.
We cut out the nodes along the marks, set them in place, fasten them with corners, duplicate the lower nodes with brackets.

As the dimension (x) increases, the slope of the roof will increase, while decreasing it will decrease.

No. 3: Free top and hinged-fixed bottom

The ideal scheme for the construction of a pitched roof with rafters, the edges of which protrude beyond the walls. After some adjustment, it can be used in the arrangement of outbuildings.

We install the workpiece with an edge on the upper and lower Mauerlat beams with the removal of the edges outside the walls. Here you need an assistant to hold the board over the canopy.
We apply a template - a cut-off piece of board sequentially to the lower and upper Mauerlat so that the outer edge of the template coincides with the outer edge of the beams. We mark the lines of the upcoming cuts.
We select the cuts according to the outlined lines. Slightly beveled the vertical wall of the upper cut.
We install the rafter, fix it at the top with nails or corners, at the bottom with staples.
We make and install the rest of the rafters in the same way.

It is clear that mobility with its antagonist is a relative concept. However, you cannot treat them with coolness. It is required to take into account the degree of freedom of the node both during the design period and when choosing fasteners. Lack of mobility of the structure will lead to deformation, excess will contribute to instability.

No. 4: Mobility of both attachment points

A scheme with two movable nodes can be used if both fasteners have no more than two degrees of freedom. Those. horizontal mixing excludes top and bottom limiters.

Consider an example in which the rafters of an extension are laid at the top into niches cut into the wall. This means that horizontal displacement is excluded, rotation and some movement along the vertical are possible. The bottom is planted with cuttings, but in the horizontal direction it is limited by metal corners.

Actions of the builder of the "shed" step by step:

Preparing the object for work. We put a Mauerlat made of 100 × 150 timber on the brick wall of the extension. We put it on the wide side closer to the inner edge of the wall. We fasten with anchors every 80cm. In the main wall of the building at the design height, we cut grooves for the upper heels of the rafters. The depth of the cuttings is 12cm, the step between them is 70cm. If you don't want to mess around with gouging, you can use metal brackets screwed to the wall.
We make a rafter leg template. We set the blank board with the upper edge in the groove, with the lower edge on the Mauerlat. Departing from the bottom corners of the workpiece 10 cm in the horizontal direction, draw two triangular cuts.
According to the indications of the template, we make rafters. We install them, fix the position with metal corners.

The device method is valid for overlapping spans up to 4.5 m. If you need to block a larger span, the rafters will need a support group as part of the struts.

No. 5: Rigid attachment to the inclined harness

The method is used in frame construction, because it is possible to lay the support element at an angle only on racks cut at an angle. Either the racks of the frame itself, or a cantilever-running structure installed on the box, are sawn obliquely. In principle, the latter option is quite suitable for the construction of a pitched roof on concrete and brick walls.

Stages of the device of a shed roof along an inclined strapping:

Putting together the structure that creates the slope of the roof. On the gable side of the frame building, we mount short racks with the upper edge cut at an angle.
On the inclined top of the racks, we lay the board in one row for small outbuildings, in two for more serious houses.
We equip the end sides of the roof with frames in the shape of a right-angled triangle, the hypotenuse of which should repeat the slope line.
We apply the rafter to the end of the roof to mark the line of the lower cut.
We make the required number of rafter legs according to the template. We install them on the harness, fix the position of the elements with metal corners.

Without a shadow of a doubt, we will classify the latter method as the simplest category. Of all the methods of attaching the rafters to the harness and beams of the shed roof Mauerlat, this one is most conducive to attempts at independent implementation.

Final fastening work

After installing the entire row of rafter legs, we check the design position of the elements, the distance between them. We apply an arbitrary board flat to the frame of the slope, identify flaws and correct flaws. Then we fasten the rafters with staples or bundles to the walls through one in regions with medium and low wind activity. We fix each leg in areas of high wind load.

Fillets, if planned for installation, are made of material half the size of the rafter legs. Sew them on the side to the rafter. The length of the sewn-on section is on average 60-80cm.

Video for a visual study of the process

The presented methods and schemes for fastening the rafters of a pitched roof have been tested by practice. They are used most often in their "pure form". However, some adjustments according to specific specifications are not excluded.

The guarantee of the durability of a residential-type house or any other purpose will be a safe and durable roof. The quality of installation is based on the correct selection of materials, fasteners and the technology of joining structural units.

Whatever the roof, it presupposes the presence of several basic elements, among them the rafter frame, the sheathing and the roofing package can be distinguished. As for the rafter system, it is the main supporting element of the roof, which is also sometimes called the skeleton. The lathing is the ribs on which the covering material is installed. The varieties of rafter systems can be reduced to two main classes, among them hanging rafters and those called layered.

Hanging rafters

If you need to fasten the rafters to the Mauerlat, then it is important to know that the first of them can be hanging. They are formed by a triangular rigid connection of the structure, which looks like trusses. They include timber and rafter boards. In this case, the puffs are removed to the Mauerlat. The latter is a thick support bar that is securely attached to the top of the wall. Its task is to create the basis for the profile frame.

Rafters

If it is necessary to fasten the rafters to the Mauerlat, then you need to remember that the first of them can be layered. In this case, the rafter beams, which are located at an angle, have two points of support at the ends, namely a Mauerlat and a ridge bar. The latter rests through intermediate racks on the wall of the building located inside. A massive longitudinal beam can also act as a support.

Options for attaching rafters to the Mauerlat

As a feature of the building inclined frame, it is the fact that its components can have a movable and a fixed connection between them. If we are talking about a wooden building, then the last crown of a log house or a bar, which belongs to the upper trim of the walls, acts as a mauerlat. If there is a need to fasten the rafters to the Mauerlat, then the connection of the upper ends with the ridge is made articulated-movable. This also applies to the pairing of the lower part. This requirement is due to a decrease in the arising internal stresses that are inherent in the rafter frame. Such stresses are caused by temperature fluctuations, deformations of wooden buildings, house shrinkage, as well as uneven load from snow and wind. If manipulations under the ridge are carried out at a considerable height, which is not very convenient, then it is preferable to choose a rigid connection of the rafter boards. In this case, freedom of movement is left for the lower ends.

Fixing the rafter leg

When there is a need to fasten the rafters to the Mauerlat, the lower node, as a rule, is fixed in one of the following ways. The technology can be spacer, it involves the arrangement of a fixed connection unit, in this case the rafters abut rigidly against the base of the beam. The connection can be rolling. In this case, the rafter will slide along the surface of the timber, holding on to it exclusively with the help of fasteners. Both of these methods are quite widespread and have their own characteristics.

Types of fixation without a wash down and with its presence

Fastening the rafters to the Mauerlat without gash is applicable only with a sliding pairing. At the same time, the rafter leg will freely lie with its edge on the surface of the Mauerlat. In this case, corners are used as fasteners. This mounting option is not considered completely reliable under heavy loads from the roof. For this reason, it is used to bridge spans with small dimensions. In order to ensure a more reliable pairing of the components of the lower unit, the blocking saw tooth is cut out. It can be performed using a specific technology. Instead of a saw in the rafters, a persistent bar is often used, which is broken through for strength. If it was decided to fasten the rafters to the Mauerlat with staples, then the saw should be done in the rafter leg, and not in the Mauerlat. This will prevent deformation and loosening.

Types of fasteners

Fastening the rafters to the Mauerlat, the photo of which is presented in the article, can be carried out using nails and staples, as the simplest option is wire rod, which is folded in several rows. Fasteners of various types can be found on the building materials market today. Nails, which are used in the joints, exclude loosening of the fasteners. However, for this, fasteners with a notch or a so-called twisted nail should be used. If you decide to use bolts and screws, it is important to place washers or plates made of steel under them. This will prevent the fasteners from sinking.

Rules for the implementation of work on fastening rafters

If the rafters are attached to the shed roof Mauerlat, then the workpiece is placed on the ridge beam with its upper edge, while the lower corner should be connected to the inner edge of the Mauerlat. Using a piece of board that acts as a template, it is necessary to outline a line on the surface of the rafters that is parallel to the upper border of the Mauerlat. If a gash will be done, then you need to mark the persistent teeth from the inside or outside. Next, trimming along the lines is performed. When cuts are made, the markings of the corners should be observed in order to ensure a snug fit of all elements of the wooden structure. When the rafters are fastened to the Mauerlat with nails, the next step is to install the element in its place. You can now commit. If nails are used, then they must be installed at an angle through the rafter board into the beam, two on both sides. If it was decided to use brackets, then their installation is carried out from the inside of the timber approximately in the central part. Its other end is turned at a right angle towards the rafters, and then hammered into them.

Alternative use of fasteners

If the rafters are fastened to the gable roof Mauerlat using wire rod, then it must be folded in four rows, forming a clamp. With the help of it, the rafter is screwed to the Mauerlat from the outside. Most often, the connection with staples or wire is combined with other types of connections, while you get a backup fastening. Perforated mounting tape can be used instead of wire. Corners are often used. They are screwed to the upper edge of the Mauerlat on both sides of the rafter, you need to strengthen the corners to it. In order to provide more impressive reliability, the corners should be used with two rows of holes, as well as a stiffener. Instead of corners, you can use special plates that have a turn of the ends at a right angle.

If the rafters are fastened to the Mauerlat with corners, then the so-called sleds can be used. They have a sliding plate. With their help, you can provide a reliable mate that compensates for deformations. After the installation of the lower unit is completed, you can begin to connect to the ridge bar. Roofing takes half the time it takes to build a house. Material costs for it are about the same. At the same time, it is important to avoid even the smallest mistakes, which can become a source of very impressive problems when using the system.

Fixing rules

If the rafters are fastened to the Mauerlat in a wooden house, then only high-quality elements should be used. Saving in this case is unacceptable, since low-quality hardware will not guarantee the creation of a durable and stable roof. The cuts, if any, on the rafters must be done very carefully, this will avoid the need to install additional gaskets or inserts. These parts will help ensure a good connection, but are best avoided. This is due to the fact that over time they are able to deform and completely fall out. This will cause the entire structure to weaken. It is recommended to install rafters on steel plates and corners. These are best purchased before starting work on the roof. Otherwise, you will have to stop the installation for a while, which will extend the period of the manipulations. However, you can use other types of fasteners, which have been described above. But this will only be a temporary measure. To install a bar, nails and self-tapping screws are the most optimal option. To equip a durable structure, bolted connections of the type of studs are necessarily used. When installing a roof, experts recommend using sliding mounts. This technology is good for pairing rafters with a Mauerlat. The mobility of the structure is a prerequisite. Before fixing the rafters, it is necessary to prepare special recesses. They are able to provide a tight sealed fit of the elements. Templates should be used to ensure the grooves are the same. If the roof slopes are made at different angles, then the templates must be made separately. If there are cuts in the structure, then their depth should be equal to 1/4 of the width of the rafter leg. To comply with this parameter, you must additionally carry out accurate measurements.

Conclusion

When the rafters are fastened to the Mauerlat without sawing, it is important to ensure the strength and stability of the roof when exposed to strong winds. It is also important to take care of the problem of the bursting force, which has a significant impact. The roofing system must be assembled initially on the ground. This preparation is considered necessary. All measurements can be made, as well as inserts in the Mauerlat. Ultimately, you need to fit and fit the elements in place. The finished parts must be installed on the structure one by one. When purchasing hardware, you should remember that their poor quality can cause not only distortions, but also the collapse of the entire structure. It is for the same reason that it is not recommended to use a lining material, making the connection as strong as possible, since it will not loosen over time and will not suggest the need for repairs.

December 27, 2016

Are you planning to build a roof, do you need a simple structure with good strength and reliability characteristics? In this case, a single-pitched roof would be an excellent option. It will make your house, garage, extension or other structure original in its own way. In addition, the shed roof truss system is easy to install. It can be done without building experience.

Why shed

The roof structure of 1 slope has the following advantages:

When building on a pitched roof, any kind of roofing material can be used. Because the angle of inclination can be as small as possible, an almost flat roof can be built.
The sail of this design is much less than that of the dual-slope. This option can be used in areas with strong winds.
Ease of installation and operation. You can build it yourself.
Low weight compared to other types of roofing.
For a pitched roof, slopes can be built in several floors. This solution will add design to your home.
The construction of a pitched roof is the most economical and does not take much time.
In this design, the water rolls down only one side.
The roof is suitable for any type of building.

Like any other design, a pitched roof has several disadvantages:

With a small angle of inclination, the area of the attic space is minimal.
Has a less attractive appearance. What can be fixed if there is a designer's imagination.

Structural calculation

The shed roof rafter system, in fact, consists of layered rafter legs. You need to fasten the rafters parallel to each other. The rafters, in turn, are supported by two points. Basically, they are the load-bearing walls of the building.

Create a ramp angle

The required slope angle of the slope is achieved in several ways:

When developing a building project, one of the walls on which the rafter legs will lie is made slightly higher. This method is common, as it greatly simplifies the design of the rafters. But in this case, more material will be spent on the construction of the walls. The side walls running parallel to the rafters are trapezoidal.
This method is a variety 1. Also, when planning, the frame racks are taken into account. In this version, the extreme posts on one side are higher, and on the other they are lower by a certain height.
With the same height of the walls, vertical posts of the required height are installed on one of the walls. At first glance, this design is unstable, since the rafter triangles have free play to the right and left. But this fragility of the structure is eliminated when installing the frame lathing and sheathing the front part of the roof with wood.
Single-pitched farms can be used. This method is good enough in that you can build one truss, adjust it to the desired dimensions and use it as a template. And using the template, you can build the rest of the farms on the ground. There are ready-made roof trusses. They are ideally suited to any type of roofing. For them, it is enough only to install and fasten to the Mauerlat. Further, you can freely sheathe a pitched roof with a crate.
When building an extension near the house, this method is used. In this case, racks or a wall can be planned on one side of the extension, and on the other, we already have the main wall of the finished building. Attachment to it can be done using a well-fixed horizontal girder or separate fasteners, also horizontally aligned. All fixings on the wall of the building are made above the posts or the wall of the opposite side.

Determine the side of the roof slope

Often the question arises, in which direction to determine the roof slope? In the case of an extension to the house, there are no special options. The slope is made in the direction from the building to ensure free flow of water in case of heavy rains.

If a separate building is planned, then here you can choose a side. Basically, the location of the ramp is done on the back of the building. Although there are times when the slope is produced on the front side. In such a situation, the choice is based on the design style of the building, the territorial features of the site, from which side it is more convenient to lay the communication system, and the like.

But in this case, you should also not overlook some of the nuances:

The location of the pitched roof in the windy direction will be more correct. Thus, the impact of the wind is minimized. After all, the wind directed into the roof with a small angle has practically no effect on it.
For a rectangular building, you can choose the location of the slope along or across. But here it must be remembered that the rafters of a pitched roof cannot have unlimited length. For some distance, they need to be strengthened. According to the rules, the free size of the rafters is 4.5 meters. When installing a rafter system up to 6 meters, a rafter leg is required. It is placed at an angle of 45 degrees on the support bar.

The steepness of the slopes

If we are talking about a pitched roof, then in most cases the angle is not chosen up to 30 degrees. This choice is explained by the fact that the roof is highly vulnerable to wind load on the front side of the building. Although they try to build the slope of the slope from the windy side, this does not exclude the presence of wind from the side of the facade. Therefore, a steep angle of inclination creates a high lifting force. In strong winds, a high load falls on the roof structure.

A slope below 10 degrees is also unacceptable, as the load on the rafter system immediately increases during snowfall. With the beginning of the thaw, an ice crust appears at the edge of the roof, preventing the free flow of melt water.

The material of the roof covering is important for determining the angle of the slope. Indeed, for different materials, the manufacturer also indicates its own slope angle.

Depending on the material, some standard values for the slope angle can be distinguished:

Up to 2 degrees - almost flat roof. It requires at least 4 layers of coiled bitumen coating. It should be applied using hot technology. It also requires a gravel dressing embedded in the mastic.
3-5 degrees - assumes three layers of roll coating. You don't need to use gravel powder.
9-15 degrees - with roll material, 2 layers are enough. You can also use some types of corrugated board or metal.
10-17 degrees - you can lay corrugated slate with a reinforced profile.
11-20 degrees - soft bituminous shingles.
14-25 degrees - asbestos-cement slate, at 25 degrees, corrugated board and metal tiles lay down practically without restrictions.
27-50 degrees - ceramic, cement tiles.

Mounting

When building a shed roof with your own hands, for a correct and reliable installation, you need to use the drawings and detailed instructions, which will indicate all the dimensions and the amount of the required material. You can create a schematic drawing yourself or find a ready-made sample on the Internet. You can also order it from construction professionals.

Before starting construction, you need to choose a ventilated or non-ventilated type of roof. The first is great for living quarters, as ventilation provides a comfortable microclimate inside the building. All this is achieved by using gaps between waterproofing materials. The second type is suitable for the construction of a terrace or storage room.

Construction of rafters with a pitched roof

The rafter system of a single-pitched roof involves a couple of popular methods for its installation:

Fastening the rafters of the pitched roof to the load-bearing walls. In this case, the roof will turn out to be more economical and less lumber will be used for it. The load-bearing wall must be at the same height as the roof. Since the upper part of the rafter rests against it.
A triangular truss is constructed, which includes beams and racks. She will unite the structure of the rafters. With this method, you do not have to build a load-bearing wall to the height of the roof, but more wood will go. This method is convenient because you can mount all the farms below using a template.

When erecting rafters, additional supports and struts will be needed. The number of such complementary elements depends on:

Slope of the slope.
Weights of the rafters.
The length of the junction points between the roof and the wall.
Roof material.
Insulating layer materials.

Rafter step

The distance between the rafters can be determined by the box on which the roof is being erected. So that the distance between the rafters is the same, the slopes on which the rafter legs rest are divided into equal sections. Depending on the materials to be installed, some values can be distinguished:

For rafters from a bar, the step is from 1.5-2 meters.
When using paired boards, the distance between the rafters is 1-1.75 meters.
The use of single boards relies on a pitch of 0.6-1.2 meters.

Also, the type of insulation affects the distance between the rafters. It is recommended that the thermal insulation layer is rigidly installed between the rafters. After installing the rafter system, you can go to the Mauerlat. It will help distribute the load on the walls.

Nuances of Mauerlat installation

Mauerlat is a complementary element to any roof. The lower edge of the rafter is installed on it. It is fastened to the load-bearing wall or between the beams of the rafter system. For fastening the Mauerlat, it is necessary to use reinforcement, if the walls of the house are made of porous material, burnt wire, if the walls are brick, anchor bolts for a wooden house.

To extend the life of the Mauerlat, you need to install it on a waterproofing layer.

Floor beams, their installation

In addition to the Mauerlat, for some designs of pitched roofs, the installation of floor beams is implied. The rafter legs rest on them. Such beams are mounted with a step similar to the rafter system. Fastening the rafters to the Mauerlat is always done with a saw. The gap between the rafters and the Mauerlat is minimized.

With a rafter system of more than 4.5 meters, rafter legs are installed. They give strength and eliminate deflection of the rafter beam. The installation location depends on the width of the spans. A gable roof of a huge area, without exception, should include rafter legs. Otherwise, it threatens to break or collapse.

It must be remembered that when increasing the step between the rafters, you will have to reduce the step of the sheathing or make it solid.

When installing a pitched roof, do not forget about some of the nuances:

You need to place the slope on the windy side. To prevent the roof from being blown off by the wind.
When calculating the rafter system, you need to take into account the climatic conditions. This is the amount of snowfall, heavy rains, wind strength. The even distribution of the load on the rafters will increase the service life.
Consider overlap when calculating materials.
The smaller pitch of the rafters of the pitched roof allows you to withstand higher loads.

An example of a lean-to garage design

The walls are built of foam blocks. The first step is to install the Mauerlat. With a pitched roof, these are 2 beams laid on walls of different heights.

A phased scheme for the construction of a rafter system consists of:

On the inner sides of both walls, we install a beam of 100x150 mm. Its installation is carried out on a waterproofing material roofing material. This will be our Mauerlat. Mauerlat fasteners are made using reinforced corners 90x90. For this we use dowels with a diameter of 14 mm.
We take a board of 50x200 mm and install it on the Mauerlat with a margin of 50-60 cm. The stock should exceed the planned dimensions of the cornice. After that, all unnecessary is cut off.
We mark further cuts on the board, the depth of which should not be more than 1/3 of the board's width.
We mark the walls so that the last rafters do not touch them. The recommended distance is 4-5 cm.
Using the template, we make the rest of the rafters. We fix it with staples or corners.
Taking into account the width of the overhang, we produce filly. We mount all the elements of the cornice so that there is a layer of waterproofing between the tree and the wall.
We cut off all the surplus and fasten the 25x100 mm wind board.

The simplest scheme for the construction of the garage has been completed. The next steps will be to install the sheathing and decking of the roofing material.

What is the peculiarity of a pitched roof

The advantages of a gable roof include the following positions:

The weight from the rafters and power trusses in the roof frame does not create bursting forces, as is the case with gable options;
The rafters of a single-pitched roof, even with a large roof span, do not require the use of a massive and thick beam, as for more complex two and four-pitched options. The main part of the load is transferred by the rafter system to the floor beams and walls of the building using struts, racks or load-bearing support trusses made of a conventional 50th plank;
The use of a pitched roof often becomes the only possible option if you need to add an extension to the main wall of the house, as in the photo, or even make a roof over the balcony.

Features of the use of a pitched roof

In addition to the listed advantages and simplicity of the device, the single-pitched rafter system has its own specifics, which should be taken into account when planning the roof parameters:

Advice! The most preferable way of arranging a pitched roof would be the option of an extension to the main wall of the finished building.

Shed roof rafters

Installation of a rafter system from short beams

Roof device made of long rafters

Installation of a simple truss system on transverse truss frames

Various assembly options for mounting rafters on a pitched roof

In addition to the above variant of assembling the frame for a pitched roof, in practice, simpler and more affordable ways of attaching the rafter system are often used.

Conclusion

Installing rafters for a pitched roof is no more difficult than assembling a frame for a gable roof. If you have experience working with spatial structures made of wood, like a garden house or a shed of your own construction, even a novice carpenter is quite capable of making a roof for an extension to a house.

Bikrost TKP
Chimney for a brick oven in a bath
Hipped roof
Shed roof rafter system

In this article I want to tell you how a simple pitched roof is erected. Why did I call it simple? Simply because her roof truss consists of only rafters. No racks, struts, braces, etc. there is no. This type of roof is most often used in the construction of small garages, sometimes baths, various extensions to the house, any outbuildings, etc.

In general, when you read about single-pitched roofs in the literature or the Internet, you usually see such a statement - supposedly they are the cheapest, simplest to construct and reliable.

As for the cheapness and simplicity - I absolutely agree, but at the expense of reliability - I'm ready to argue.

Of course, maybe I live in the wrong climatic zone, but in my practice I have never seen a roof with two or more slopes collapse on a private low-rise building (for example, hip, hip, etc.). All the collapses that have ever occurred were on pitched roofs. They are almost always caused by snow loads plus the weight of people who work on the roof (for example, throwing off the same snow).

So why is this happening. I think everything is simple here. Often, developers are not very serious and deliberate in their approach to the construction of a pitched roof. Basically, one of three mistakes is made, or several at once:

An unacceptably small angle of inclination of the ramp is made;

As rafters, boards with an unsuitable section are used;

Too large a step is made between the rafters.

How to avoid these mistakes, we will now understand the example of the construction of a pitched roof over a garage.

Let's say we have a box made of foam concrete blocks with a wall thickness of 30 cm. Its dimensions are shown in Fig. 1.

Picture 1

Having started laying blocks, we must already decide on the angle of inclination of the roof slope. What should be guided by here?

I think many people know that for each roof covering there is a minimum slope angle at which it can be used. These values are presented in table 1., compiled on the basis of SNiP II-26-76 * ("Roofs" - updated version of 2010):

Table 1.

I am sure that some of you who have already studied similar tables on the Internet will be a little embarrassed when they see such numbers. I want to tell them about a little confusion that has formed on various construction sites due to the banal carelessness of their authors. Often, when making such a plate, they take the numbers from the above-mentioned SNiP II-26-76 *, but do not notice that in this document the angles are indicated in percent (%), and not in degrees, as we used to measure them from school. I will not explain now how to convert percentages to degrees. There is this information on the network (there are formulas, there are also tables). In principle, we do not need this.

Now for another remark. Each manufacturer of any roof covering (be it metal, or bituminous shingles, etc.) sets the minimum angle of inclination of the roof for its products. It is indicated in the installation instructions. For example, for different manufacturers of metal tiles, you can see the numbers at 14 °, 16 °, etc. Often these figures are higher than those determined by SNiP and indicated in Table 1.

But that's not all. All the figures given above characterize the angle of inclination of the roof, at which the given roofing will not overflow between adjacent elements under certain weather conditions. And these conditions in our country are very, very diverse. So snow loads differ significantly in different climatic zones. And wind farms in general may differ within one settlement, depending on the location of your building relative to others.

Snow loads affect the possible deflection of the rafter system, which changes the geometry of the roofing. In addition, with a large amount of snow, a so-called "snow bag" often forms on the roof (see Fig. 2):

Picture 2

Strong winds can also push rainwater through the joints of the roof elements.

At one time I looked through many different sources, but nowhere did I find a specific dependence of the minimum angle of inclination of the roofing on the climatic conditions in the region. As I understand it, no one took her out. All use values based on previous years of experience. I can say that for pitched roofs, in central Russia, it is usually not recommended to make the slope angle less than 20 °. We will also build on this value.

So, let's say in our garage (Fig. 1) we decided to make the slope angle of the ramp equal to 20 °. We will cover it with corrugated board. Now we need to decide how high the walls should be laid out. In this case, we make a low wall 2.4 meters high. This value is chosen in each case individually, depending on your personal preferences and the characteristics of your building. The height of the opposite wall is determined by a simple formula:

Н в = Н Н + В × tg α,

where H in - the height of the high wall;

H n - the height of the low wall;

B - the width of the building (garage);

α is the angle of inclination of the slope.

In our case, Н в = 2.4 + 4.8 × tg 20 ° = 4.2 m. (Rounded up a little).

Now you can start laying the foot of the garage. Please note that the last row is not laid at the high wall. Why, it will become clear later.

STEP 1: We begin construction of the roof with the installation of the Mauerlat. We use a beam of 100x150 mm as a Mauerlat (Fig. 3). It fits flush with the interior walls. Notice how the sloped wall is laid out.

Figure 3

Also, instead of a bar, you can use two boards 50x150 mm stitched together with nails. I wrote about such an example in an article on installing a Mauerlat. It describes several ways to fix the Mauerlat on the wall. In addition to them, I want to show you one more, which we sometimes use when erecting a roof on gas and foam concrete walls, when the customer does not want to make an armored belt (Fig. 4):

Figure 4

Reinforced roofing corner 90x90 is used here. We fix it to aerated concrete using two GBʺ dowels with a diameter of 14 mm. They hold great. We put such corners on the Mauerlat after about 80-100 cm.

Please note that roofing material must be placed under the Mauerlat so that there is no contact between wood and aerated concrete and metal. In all subsequent drawings, roofing material is simply not shown, but its presence is required.

STEP 2: We start installing the rafters. To do this, first of all, we need to decide on their section and the step between them. In this we will again be helped by the program described in the article ʺRoping system. Calculation of rafters and floor beamsʺ ().

I would like to clarify again. I am not the author of this program. But I always use it, for lack of anything else (more or less understandable). I am completely confident in the strength of the roofs that we have already built. This confidence comes during the construction process, when you yourself climb the rafters and when you examine the rafter system a few years after the construction of the house (I have such opportunities).

The program is certainly not perfect and sometimes you yourself have to make some assumptions. Therefore, do not judge strictly. The main thing is that all these assumptions work towards increasing the safety factor of the rafters and beams.

Let's go back to our garage. Let's choose the region - Moscow region as an example. The sum of snow and wind loads will be 196 kg / m 2. Where this figure comes from, I described in detail in the article (link above). I think there is no point in repeating. By the way, just here I make one assumption in the calculation. In the program, when entering the initial data, only the value of the snow load is requested (Fig. 5). There are no graphs for entering the wind load at all. Therefore, I simply add it to the snow, although I know that it acts in a different direction (snow - from above, wind - from the side).

Figure 5

We have introduced the step of the rafters 0.5 meters. The result of the calculation (in the Sling 1 tab) is shown in Figure 6. For the rafters, boards with a section of 50x200 mm were selected. Of course the step is too small, but where to go. If we take it equal to 0.6 meters, then this section does not pass the calculation. Of course, you can take, for example, a 150x100 timber as rafters, then the minimum step will change. Here you can already improvise. I'm used to working with boards either 50x150 or 50x200 mm.

Figure 6

By the way, in the figure, the distance between the supports (4.2 meters) is the inner width of our garage.

Having determined the cross-section, we mark the rafters cuts. We take a board of 50x200 mm of a suitable length and place it on the Mauerlat (see Fig. 7). It should hang from the walls with a margin (we got 53 cm), so that after the final trimming, the cornices are 40-50 cm wide.

Figure 7

Now, using either a square or a tape measure with a small level, we mark the lower and upper cuts. In this case, we make the width of the cut equal to the width of the Mauerlat - 150 mm. The depth of the cut will be 48 mm (see Fig. 8). Such exact values are given to me by the program in which I draw a three-dimensional model of the roof (Google SketchUp). In real work, of course, there will not be such accuracy down to a millimeter, but it is not really needed there.

In other articles, when considering roofs with large slope angles, such cuts are performed not based on the width of the Mauerlat, but based on the maximum allowable depth of the cut. It is usually 1/3 of the rafter section height. Now we have 1/3 of 200 mm - that's 66 mm. We fit into this meaning. And it makes absolutely no sense to make the width of the saw more than the width of the Mauerlat.

Figure 8

So, we got a template according to which we make all subsequent rafters and install them (see Fig. 9):

Figure 9

The outer rafters do not touch the inclined walls. You can see this in the picture above. The gap is about 5 cm.

STEP 3: We make and install cornice filly (see fig. 10):

Figure 10

We make them from boards of the same section as the rafters. Roll out roofing material on an inclined wall before installing the fillies. It is not shown in the figure.

The sequence is as follows. First, we put the two extreme filly and pull the lace between them (see Fig. 11):

Figure 11

Then, with a step of about 0.8-1 m, we install the rest (see Fig. 12).

Figure 12

Fasten the filly with 2 nails (120 mm) hammered into the end through the rafter. The outer fillets can be fixed with roof corners directly to the sloped wall.

STEP 4: We install end (wind) boards (see fig. 13):

Figure 13

We use inch boards 25x200 mm.

Also, we need to lay the Mauerlat on a high wall (see Fig. 14). This can be done either with aerated concrete or with ordinary brick. Again, the tree should be separated from the other material with a layer of roofing material.

Figure 14

STEP 5: We sew the cornices from below. This is done depending on the final finish of the roof. The cornices are either sewn up completely, or, as in our case, only the belts are sewn under the subsequent siding finish (see Fig. 15):

Figure 15

It is enough to use boards of 25x100 mm as belts.

STEP 6: Now we make the crate (see fig. 16):

Figure 16

The required section of the battens can be determined in the program that is used to calculate the rafters and beams (see Fig. 5). In our example, boards with a section of 25x100 mm are taken, their pitch is 350 mm. In the picture we see the inscription - "The bearing capacity of the crate is provided".

As a base for the corrugated board, which we want to cover this roof, in order to save money, you can use unedged inch boards. But you only need to take the so-called "second board" (see fig. 17):

Figure 17

The price of such material is almost 2 times lower than that of edged material. There is only one very important remark. Before laying the boards on the roof, it is imperative to peel off the bark from them. Beetle (bark beetle) larvae often live under it, which first eat the bark, and then proceed to the wood itself. It is quite difficult to get rid of them later. Some say that it is impossible at all.

STEP 7: Well, the rafter system is ready. Now we cover the roof with corrugated board and sheathe the cornices with siding (see Fig. 18):

Figure 18

Thus, we made a non-insulated pitched roof. It is clear that this design is only suitable for cold rooms. If we are going to heat the room, then the roof will need to be insulated. Let's see what additional work needs to be done for this.

We do the first five steps in the same way as described above. Then we expose the plugs for laying the insulation (see Fig. 19). We make them from an inch (board 25 mm thick).

Figure 19

Now we lay the insulation. From the bottom to the rafters, a vapor barrier film should be hemmed. It is not shown in the figure.

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