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Variations of execution truss structure gable roof mass. Its appearance will largely depend on what it will be attic space heated or cold, depending on availability load-bearing partitions, choice roofing material and, of course, from taste preferences developer. Despite the variety of roof structures (rafter system and roofing pie), the basic installation rules remain unchanged.

The main stages of installing a gable roof

Gable roof projects

Before starting the installation of the roof, it is necessary to draw the external shapes of the future frame, indicating its configuration and height, so that in total the gable roof looks proportional in relation to the overall structure, in a word - to clearly imagine the structure of the gable roof rafters. This can be done in any way convenient for you, the main thing is to maintain the scale for a real vision of the prospects. From experience we can say that optimal height The roof is considered to be 1/3 of the length of the house. Here we implement our ideas regarding a straight or broken slope, branching in the main lines (Fig. 1), residential or non-residential attic space and the type of roof itself, it can be hanging or layered. The latter option is more often used when constructing gable roofs, since it is more practical and economical in terms of lumber consumption.

After you have decided on appearance and the functional purpose of the structure, it is necessary to draw a diagram of the rafter system and make its layout in projection. This is necessary in order to calculate required amount material for roof construction.

The expenditure item of the total budget for roof installation will largely depend on how complete and rational the calculations are made. For example, if you know in advance that you will need N amount linear meters timber, then when cutting you need to take into account standard length lumber and rafter leg size. As a rule, long structural elements have to be made into joints, so without proper cutting, you can get an inflated percentage of waste.

Despite the fact that gable roofs are considered the most convenient and economical in terms of laying roofing, it is not superfluous to calculate the amount of sheet or piece material. Since the installation of each of them has its own characteristics, the need for overlap, the number of ridges or waves, technical features (one-sided capillary groove), etc., when calculating the total surface area, it is necessary to take into account all these subtleties.

The height of the slate wave and the thickness of the sheet also matter if slate is chosen as a roofing material.

According to GOST 30340-95, 8 wave and 7 wave slates are produced with the following parameters: wave height h – 40 mm, wave pitch (distance between adjacent ridges) – 150 mm, and sheet thickness – 5.2 or 5.8 mm.

Example of consumables calculations

IN ideal, when the installation of a gable roof is carried out according to the project, a selection of all structural elements is made, indicating the length and quantity of each position. Using a rational cutting system, the volumes are summed up by:

• Lumber (m.p.)
• Insulation (m2)
• Vapor barrier membrane (m2)
• Roofing covering (quantity in pieces, m2)

For clarity of calculations, we will take as a basis a house with specific dimensions

• Width(s) – 5 m
• Length (h) – 8 m
• Apex angle () – 1200
• Slope angle (A, C) – 300

We start by calculating the height of the roof, it is calculated as follows

h = ½ x a/ tg /2 = 0.5 x 5/ 1.73 = 1.44 mm

rafter length (AB) according to the theorem right triangle, will be equal to the product of ½ the width of the house divided

by sine of ½ vertex angle

L(AB) = 1/2 x a / sin /2 = 1/2 x 5 / 0.87 + 0.5 = 2.87 m

To the resulting length, do not forget to add the length of the eaves overhang; it is determined in the range of 0.5 ÷ 0.8 m. Therefore, the final size of the rafter leg will be equal to 2.87 + 0.5 ÷ 0.8 = 3.37 ÷ 3.87 m (let's stick to the 3.5m option)

S over. roof = a x L(AB) x 2 = 5 x 3.5 x 2 = 35 m2

This is not a total figure for the amount of roofing material that will be needed to cover the roof. To it you will need to add the percentage of waste based on the cutting according to the roof configuration. For each option it will be individual, so the final result will be known after specific calculations.

Lumber for sheathing is also easy to calculate. The pitch between the battens (m) is taken to be 300 mm. Total

M = L(AB) / m x b = 3.5 / 0.3 x 8 x2 = 187 l.m.

We calculate the board for the rafters in the same way. The pitch between the rafters is set, it can vary from 600 to 1000 mm, the cross-section of the board, the weight of the roofing pie are taken into account, and not the least role is played by the multiplicity, which is dictated by the width of the heat-insulating mats and the size of sheets of moisture-resistant plywood or OSB boards when making a continuous sheathing.

All other elements are calculated according to the given scheme.

Set of tools for constructing a roof

Once you have completely decided on the designs of the rafter system and the roofing pie, you can adjust the classic list of tools that you will need to build the roof. It is very convenient to have a belt for tools when working at the top, so they will always be in one place and at hand. Its kit should include:

• Roulette
• Pencil or marker
• Lace (beat)
• Hammer
• Roofing shears
• Putty knife
• Roofing knife
• Construction tape
• Hacksaw
• Screwdriver with screw attachment

In some cases, mastic-based adhesives and polyurethane foam may be needed.

Some devices greatly simplify the installation process, such as templates and slats with markings.

Roofing details

It is also worth paying attention to the so-called roofing details, which the developer often does not pay attention to, but they also affect the functionality and durability of the roofing system. The use of low-quality self-tapping screws (without the manufacturer's mark and with a thickness of EPDM gaskets less than 2 mm) leads to roof leaks. The weak paint coating on the fittings can break down and ruin over time. appearance roofs. Another element that is important when constructing a roof is snow retainers; their absence increases the risk of an avalanche of snow falling from the roof. This in turn may lead to damage drainage system, buildings or cars located under the roof. The next problem that worries developers is the problem of condensation, which is associated with insufficient ventilation of the under-roof space. To improve air exchange, it is necessary to provide for the installation of ventilation outlet elements in the roof surface; they allow you to ventilate the under-roof space more intensively, and therefore avoid the problem of condensation.

They also forget to prescribe antiseptic compounds as an item in the expense item, without which it is impossible to imagine modern construction made of wood.

Gable roof rafter system. Installation and its features.

The installation begins with the installation of a support beam - Mauerlat. It is installed on load-bearing walls and secured using pre-built anchor bolts or metal studs. The accuracy of installation of the entire rafter structure depends on how smoothly the Mauerlat is mounted. His straightforwardness

checked using a level; if necessary, leveling is done using linings or trimming off protruding parts. The flatness of the support beam allows you to use one template to make all the table legs on the ground, rather than having to adjust each one in place. It is recommended to carry out the support of the rafters on the mauerlat using one of the methods indicated in Figure 3.

It is highly undesirable to cut on a mauerlat or on a ridge run; this can reduce the load-bearing capacity of the supporting elements.

If the project provides for a ridge girder, and this is a more reliable option, the next step is to install a beam at the top point of the gables. Fastening units A and B in Fig. 1 are made according to the diagrams shown in Fig. 4

The ridge girder is made from 50x200-250 mm boards, the ends of the beams are treated with an antiseptic compound and wrapped with waterproofing material, the end part is left open for air access. Assembling a rafter structure with a ridge girder is much easier than without it. The fact is that the presence of a longitudinal beam allows you to install a pair of rafters separately, which saves time and labor costs.

Roofing pie device

Upon completion of the installation of the rafter system, they proceed to laying the vapor barrier layer. The rolled material is rolled out parallel to the ridge girder and attached to the rafters on the inside of the roof. Butt joints are made overlapping and sealed with tape.

From above, the space between the rafters is filled with insulation. To ensure protection of thermal insulation from moisture due to possible roof leaks or condensation forming on the inner surface of the roof covering, under-roof waterproofing is installed. She gets nailed with outside rafters with nails or staples and secure the counter battens with bars.

Next, the sheathing is installed; its design is selected depending on the roofing material. With the help of counter battens and sheathing, a ventilated gap is created, this ensures the air-dry condition of all roof materials.

Laying roofing is the final stage in the roof structure. It is applied according to the manufacturer's instructions. At the end of the main work, they begin to assemble and install drainage systems, ventilation, snow guards and ladders for Maintenance roofs.

Roof installation is a complex multi-step process. To independently assemble and install a rafter system, you need to carefully study the methods of connecting elements, calculate the length of the rafters and the slope angle, and select the appropriate materials. If you don’t have the necessary experience, take on complex designs not worth it. The best option for a residential building small sizes– do-it-yourself gable roof.

A standard roof of this type consists of the following elements:

Mauerlat is a timber laid on top of the walls along the perimeter of the building. It is secured using threaded steel rods embedded in the wall or anchor bolts. The timber must be made of coniferous wood and have a square section of 100x100 mm or 150x150 mm. The Mauerlat takes on the load from the rafters and transfers it to the external walls.

Rafter legs- these are long boards with a cross section of 50x150 mm or 100x150 mm. They are attached to each other at an angle and give the roof a triangular shape. The structure of their two rafter legs is called a truss. The number of trusses depends on the length of the house and the type of roofing. Minimum distance between them is 60 cm, the maximum is 120 cm. When calculating the pitch of the rafter legs, you should take into account not only the weight of the coating, but also the wind load, as well as the amount of snow in winter period.

It is located at the highest point of the roof and most often represents a longitudinal beam connecting both slopes. The beam is supported from below vertical racks, and the ends of the rafters are attached to the sides. Sometimes the ridge consists of two boards that are nailed to the top of the rafters on both sides and connected at a certain angle.

Racks are vertical beams with a cross section of 100x100 mm, located inside each truss and used to transfer the load from the ridge run to the load-bearing walls inside the house.

The struts are made from scraps of timber and installed at an angle between the posts and rafters. Strengthened with struts side faces trusses, the load-bearing capacity of the structure increases.

Tie - a beam connecting the lower parts of the rafters, the base of the truss triangle. Together with the struts, such a beam serves to strengthen the truss and increase its resistance to loads.

A log is a long beam with a cross section of 100x100 mm, laid along the central load-bearing wall, on which the vertical posts rest. Lezhen is used when installing layered rafters when the run between the outer walls is more than 10 m.

The sheathing consists of boards or timber placed on the rafters. The sheathing can be continuous or with gaps, depending on the type of roof. It is always attached perpendicular to the direction of the rafters, most often horizontally.

If there is no more than 10 m between the external walls and there is no load-bearing wall in the middle, arrange hanging rafter system. With this system, the upper ends of adjacent rafters are sawn at an angle and connected to each other using nails, excluding the installation of racks and ridge beams. The lower ends of the rafter legs rest on the external walls. Due to the absence of racks, the attic space can be used for arranging an attic. Very often, the function of tightening is performed by floor beams. To strengthen the structure, it is recommended to install the top tie at a distance of 50 cm from the ridge.

If there is a central supporting wall, the arrangement is more justified layered rafter system. A bench is laid on the wall, support posts are attached to it, and nailed to the posts ridge beam. This installation method is quite economical and easier to implement. If ceilings in interior spaces are designed at different levels, the racks are replaced with a brick wall dividing the attic into two halves.

The roof installation process includes several stages: attaching the Mauerlat to the walls, assembling the trusses, installing the rafters on the floors, installing the ridge, and attaching the sheathing. Before assembly, all wooden elements are carefully treated with any antiseptic composition and dried in air.

To work you will need:

• timber 100x10 mm and 150x150 mm;
• boards 50x150 mm;
• boards 30 mm thick for lathing;
• roofing felt;
• metal studs;
• jigsaw and hacksaw;
• hammer;
• nails and screws;
• square and building level.

In wooden houses The functions of the mauerlat are performed by the logs of the last row, which significantly simplifies the work process. To install the rafters, just cut inside log grooves of the appropriate size.

In brick houses or buildings made of blocks, installation of the Mauerlat occurs as follows:

The Mauerlat bars must form a regular rectangle and be in one horizontal plane. This will facilitate further installation of the roof and provide the structure with the necessary stability. Finally, markings are made on the beams for the rafters and grooves are cut along the thickness of the beam.

When choosing a hanging rafter system, it is necessary to assemble the trusses on the ground and then install them above the floors. First you need to draw up a drawing and calculate the length of the rafter legs and the angle of their connection. Typically, the roof slope is 35-40 degrees, but in open, heavily blown areas it is reduced to 15-20 degrees. To find out at what angle to connect the rafters, you should multiply the angle of the roof by 2.

Knowing the length of the run between external walls and the angle of connection of the rafters, you can calculate the length of the rafter legs. Most often it is 4-6 m, taking into account the eaves overhang 50-60 cm wide.

The upper ends of the rafters can be fastened in several ways: overlapping, end-to-end and “into the paw”, that is, with grooves cut out. Metal plates or bolts are used for fixation. Next, the lower and upper ties are installed, and then the finished trusses are lifted up and installed above the floors.

The outer trusses are attached first: using a plumb line, the rafters are aligned vertically, the length of the overhang is adjusted and attached to the mauerlat with bolts or steel plates. To prevent the truss from moving during installation, it is reinforced with temporary beams made of timber. After installing the outer rafters, the rest are set, keeping the same distance between them. When all the trusses are secured, take a board with a cross-section of 50x150 mm, the length of which is 20-30 cm longer than the length of the cornice, and nail it along the upper edge of the slope. The same is done on the other side of the roof.

The first option: a rectangular groove is cut out on the rafter leg at the point where it contacts the mauerlat, 1/3 of the width of the beam. Stepping back 15 cm from the top of the box, a steel spike is driven into the wall. The rafter is leveled, the grooves are aligned, then a wire clamp is placed on top and the beam is pulled close to the wall. The ends of the wire are securely fastened to the crutch. The lower edges of the rafters are carefully cut off circular saw, leaving an overhang of 50 cm.

Second option: the upper rows of walls are laid out with a stepped cornice of bricks, and the mauerlat is placed flush with inner surface walls and cut a groove in it for the rafter. The edge of the rafter leg is cut to the level top corner cornice. This method is simpler than others, but the overhang is too narrow.

Third option: beams ceilings are released over the edge outer wall by 40-50 cm, and the trusses are installed on the beams. The ends of the rafter legs are cut at an angle and rest against the beams, secured with metal plates and bolts. This method allows you to slightly increase the width of the attic space.

Installation of layered rafters

Figure 1 shows the cutting of rafter struts into a beam laid on intermediate supports, and Fig. 2 - resting the rafter leg on the mauerlat

The procedure for installing a layered rafter system:

When the main elements are fixed, the surface of the rafters is treated with fire retardants. Now you can start making the sheathing.

For the sheathing, timber 50x50 mm is suitable, as well as boards 3-4 cm thick and 12 cm wide. Waterproofing material is usually laid under the sheathing to protect the rafter system from getting wet. The waterproofing film is laid in horizontal strips from the eaves to the roof ridge. The material is spread with an overlap of 10-15 cm, after which the joints are secured with tape. The lower edges of the film should completely cover the ends of the rafters.

It is necessary to leave a ventilation gap between the boards and the film, so first stuff them onto the film. wooden slats 3-4 cm thick, placing them along the rafters.

The next stage is covering the rafter system with boards; they are stuffed perpendicular to the slats, starting from the roof eaves. The pitch of the sheathing is influenced not only by the type of roofing, but also by the angle of inclination of the slopes: the greater the angle, the greater the distance between the boards.

After completing the installation of the sheathing, they begin cladding the gables and overhangs. You can cover the gables with boards, plastic panels, clapboard, waterproof plywood or corrugated sheeting - it all depends on financial capabilities and personal preferences. The sheathing is attached to the side of the rafters; nails or screws are used as fasteners. Overhangs are also hemmed various materials– from wood to siding.

Video - DIY gable roof

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It's hard to imagine a house without a roof. Without it, the house cannot be called complete. The roof, as you know, protects the house from precipitation, inclement weather, etc. In addition, it is used to complete the architectural image of the constructed object. In this case, it is necessary to correctly calculate and install the roofing system, only then will the roof last for many years and will not need to be repaired every year.

The structure of the rafters can be very different. We propose to consider their most common types and types, methods of their fastening.

As you know, the roof can be flat or pitched. Concerning suburban construction, then in this case the installation of a gable roof rafter system is especially popular. If the house is very large, then the roof will be of the appropriate size, for example, hipped (more details: ""). Thus, the developer must imagine the design of the rafter system hipped roof. The most simple option The installation of a truss system for a pitched roof is considered, since it is very labor-intensive and requires sufficient knowledge.

Still, it is worth noting that the structure of the rafter system gable roof today it is considered the most common option. The design consists of two planes that are on the same level. They are also the load-bearing part that rests on the walls of the house. Usually there is an attic under the roof slopes. If it is heated, then it can be used as attic floor, where you can arrange a functional room.

It is worth noting that the angle of inclination of the future roof will depend on the roofing material. It is usually measured in degrees.

Determining the reliability of the rafter system

When installing a roof, developers pay special attention to the rafter system. It must be made reliable, because the service life of the roofing structure depends only on this system.

The reliability of the rafter system is usually affected by the following points:

Construction of a rafter roof: structural components

We can conclude that if the rafter system is calculated incorrectly and unprofessionally, it may simply not withstand the load in the future. In this case, terrible consequences cannot be avoided.

When calculating the design of the rafter system, the following points must be taken into account:

• roof shape;
• location internal supports;
• floor span size;
• expected operating loads.

In the design of the rafter system, the triangle is the main figure. Rafter legs are also important in such a design; maximum attention must be paid to their design. They are usually laid along the roof slope. The sheathing is supported precisely by the rafter legs.

What types of rafters are there?

Today rafters can be:

• hanging;
• layered.

The optimal sections themselves will be the following options:

• for boards – 16-18x4-5 cm;
• for bars – 16-18x12-14 cm;
• for round timber – 12-16 cm.

The axis distance between the bars and logs should be 150-200 centimeters. The distance of the rafters between the beams of the boards is usually 100-150 centimeters.

At the end of each rafter leg, so-called fillies must be nailed. A regular board is suitable for their implementation. Along the entire cornice along the slope of the filly, you need to nail the formwork, which will serve as the base for the boardwalk. It is on this decking that the roof material is attached.

The installation of a rafter system for a gable roof or any other may encounter such a difficulty as expansion (read: ""). To avoid expansion of the rafter system, the rafters must be attached to the ridge very firmly.

If the device is used incorrectly, displacement of the ramp may also occur. If rafter legs cut into the floor of a tree, this will not happen. The strength of the joint can also be achieved with an overlay, or with reliable fastenings, which are made using bolts and dowels.

In this case, it is necessary to take especially seriously the calculation of the maximum roof load, and we must not forget about the snow cap. Price roofing works in this case, it will increase significantly, since more lumber will be required, and the tiles themselves are not cheap.

Due to such high costs, many people choose soft roofing. In this case, you need to remember about the sheathing, which is made entirely of boards or plywood. This type of roof also requires underlay carpets. Therefore, when purchasing, the developer building materials You will also have to pay quite a bit of money.

A gable roof or gable roof is a roof with two slopes, i.e. having 2 inclined surfaces (slopes) of a rectangular shape.

Gable roof frame in effect design features ideally combines simplicity of design and maintenance with reliability and durability. These and many other parameters make the construction of a gable roof practical and rational decision for private and commercial housing construction.

In this article, we will look at how to make a rafter system for a gable roof with your own hands. For effective perception of the material, it is presented in the form of step-by-step instructions from A to Z, from selection and calculations, to installation of the Mauerlat and sheathing under the roof. Each stage is accompanied by tables, diagrams, drawings, drawings and photos.

The popularity of the house roof is due to a number of advantages:

• design variability;
• simplicity in calculations;
• naturalness of water flow;
• integrity of the structure reduces the likelihood of leaks;
• efficiency;
• preserving the usable area of ​​the attic or the possibility of arranging an attic;
• high maintainability;
• strength and wear resistance.

Types of gable roof

The installation of a gable roof truss system depends, first of all, on its design.

There are several options for two pitched roofs(types, types):

The most common roof installation option due to its simplicity and reliability. Thanks to symmetry, a uniform distribution of loads on the load-bearing walls and mauerlat is achieved. The type and thickness of the insulation does not affect the choice of material.

The cross-section of the timber makes it possible to provide a reserve bearing capacity. There is no possibility of rafters bending. Supports and struts can be placed almost anywhere.

An obvious drawback is the impossibility of arranging a full-fledged attic floor. Due to sharp corners, “dead” zones appear that are unsuitable for use.

The arrangement of one angle of more than 45° leads to a reduction in the amount of unused area. There is an opportunity to make living rooms under the roof. At the same time, the requirements for calculations increase, because the load on the walls and foundation will be distributed unevenly.

This roof design allows you to equip a full second floor under the roof.

Naturally, a simple gable rafter roof differs from a broken line, not only visually. The main difficulty lies in the complexity of the calculations.

Design of a gable roof truss system

Building a roof of any complexity with your own hands requires knowledge of the purpose of the basic structural elements.

The locations of the elements are shown in the photo.

• Mauerlat. Designed to distribute the load from the rafter system onto the load-bearing walls of the building. To arrange the Mauerlat, a timber made of durable wood is selected. Preferably larch, pine, oak. The cross-section of the timber depends on its type - solid or glued, as well as on the expected age of the structure. The most popular sizes are 100x100, 150x150 mm.

  Advice. For a metal rafter system, the Mauerlat must also be metal. For example, a channel or an I-profile.

• Rafter leg. The main element of the system. To make rafter legs, a strong beam or log is used. The legs connected at the top form a truss.

Silhouette roof truss determines the appearance of the building. Examples of farms in the photo.

The parameters of the rafters are important. They will be discussed below.

• Puff- connects the rafter legs and gives them rigidity.

• Run:

• Ridge run, is mounted at the junction of one rafter to another. In the future, the roof ridge will be installed on it.

• Side purlins, they provide the truss with additional rigidity. Their number and size depend on the load on the system.

• Rafter stand- vertically located beam. It also takes on part of the load from the weight of the roof. In a simple gable roof it is usually located in the center. With a significant span width - in the center and on the sides. In an asymmetrical gable roof, the installation location depends on the length of the rafters. With a broken roof and arrangement of one room per attic attic- the racks are located on the sides, leaving free space for movement. If there are supposed to be two rooms, the racks are located in the center and on the sides.

The location of the rack depending on the length of the roof is shown in the figure.

• Strut. Serves as a support for the stand.

Advice. Installing the brace at an angle of 45° significantly reduces the risk of deformation from wind and snow loads.

In regions with significant wind and snow loads, not only longitudinal struts are installed (located in the same plane as the rafter pair), but also diagonal ones.

• Sill. Its purpose is to serve as a support for the rack and a place for attaching the strut.

• Lathing. Designed for movement during construction work and fixation of roofing material. Installed perpendicular to the rafter legs.

Advice. An important purpose of the sheathing is to redistribute the load from the roofing material to the rafter system.

Having a drawing and diagram indicating the location of all the listed structural elements will help in the work.

Advice. Be sure to add information about the passage of the ventilation shaft and chimney to the gable roof rafter system diagram.

The technology of their installation is determined by the type of roof.

Selection of material for rafters

When calculating the material for a gable roof, you need to choose high-quality wood without damage or wormholes. The presence of knots for beams, mauerlat and rafters is not allowed.

For sheathing boards, there should be a minimum of knots, and they should not fall out. The wood must be durable and treated with the necessary preparations that will increase its properties.

Advice. The length of the knot should not exceed 1/3 of the thickness of the timber.

Calculation of the rafter system of a gable roof

Calculating the material parameters is an important step, so we present the calculation algorithm step by step.

It is important to know: the entire rafter system consists of many triangles, as the most rigid element. In turn, if the stingrays have different shape, i.e. are an irregular rectangle, then you need to divide it into separate components and calculate the load and amount of materials for each. After calculations, summarize the data.

1. Calculation of the load on the rafter system

The load on the rafters can be of three types:

• Constant loads. Their action will always be felt by the rafter system. Such loads include the weight of the roof, sheathing, insulation, films, additional roofing elements, finishing materials For . The weight of the roof is the sum of the weight of all its constituent elements; such a load is easier to take into account. On average the value constant load for rafters is 40-45 kg/sq.m.

Advice. To make a safety margin for the rafter system, it is better to add 10% to the calculation.

For reference: The weight of some roofing materials per 1 sq.m. presented in the table

Advice. It is desirable that the weight of roofing material per 1 sq.m. roof area did not exceed 50 kg.

• Variable loads. They act at different times and with different strengths. Such loads include: wind load and its strength, snow load, precipitation intensity.

In essence, the roof slope is like a sail and, if you take into account the wind load, the entire roof structure can be destroyed.

The calculation is carried out using the formula: wind load is equal to the regional indicator multiplied by correction factor. These indicators are contained in SNiP “Loads and Impacts” and are determined not only by the region, but also by the location of the house. For example, on a private house surrounded by multi-story buildings, there is less load. Standing separately Vacation home or the cottage experiences increased wind loads.

2. Calculation of snow load on the roof

The roof calculation for snow load is carried out according to the formula:

The total snow load is equal to the weight of the snow multiplied by the correction factor. The coefficient takes into account wind pressure and aerodynamic influence.

The weight of snow that falls on 1 square meter. roof area (according to SNiP 2.01.07-85) is in the range of 80-320 kg/sq.m.

Coefficients showing the dependence on the slope angle are shown in the photo.

Nuance. When the slope angle is over 60 ° the snow load does not affect the calculation. Because the snow will quickly slide down and will not affect the strength of the beam.

• Special loads. Accounting for such loads is carried out in places with high seismic activity, tornadoes, and storm winds. For our latitudes, it is enough to make a safety margin.

Nuance. The simultaneous action of many factors causes a synergy effect. This is worth considering (see photo).

Assessment of the condition and load-bearing capacity of walls and foundations

It should be borne in mind that the roof has significant weight, which can cause damage to the rest of the building.

Determining the roof configuration:

• simple symmetrical;
• simple asymmetrical;
• broken line

How more complex form roof, the greater the number of trusses and sub-rafter elements needed to create the necessary safety margin.

The angle of inclination of a gable roof is determined primarily by the roofing material. After all, each of them puts forward their own demands.

• soft roof - 5-20°;
• metal tiles, slate, corrugated sheets, ondulin - 20-45°.

It should be noted that increasing the angle increases the area of ​​space under the roof, but also the amount of material. What affects total cost works

Nuance. The minimum angle of inclination of a gable roof must be at least 5°.

5. Calculation of rafter pitch

The pitch of the gable roof rafters for residential buildings can be from 60 to 100 cm. The choice depends on the roofing material and the weight of the roof structure. Then the number of rafter legs is calculated by dividing the length of the slope by the distance between the rafter pairs plus 1. The resulting number determines the number of legs per slope. For the second, the number must be multiplied by 2.

The length of the rafters for the attic roof is calculated using the Pythagorean theorem.

Parameter "a"(roof height) is set independently. Its value determines the possibility of arranging a living space under the roof, the convenience of being in the attic, and the consumption of material for the construction of the roof.

Parameter "b" equal to half the width of the building.

Parameter "c" represents the hypotenuse of the triangle.

Advice. To the obtained value you need to add 60-70 cm for cutting and moving the rafter leg beyond the wall.

It is worth noting that the maximum length of the timber is 6 m.p. Therefore, if necessary, the timber for the rafters can be spliced ​​(extension, joining, joining).

The method of splicing rafters along the length is shown in the photo.

The width of the roof rafters depends on the distance between opposite load-bearing walls.

7. Calculation of the rafter cross-section

The cross-section of the rafters of a gable roof depends on several factors:

• loads, we have already written about it;

• type of material used. For example, a log can withstand one load, timber - another, laminated timber - a third;

• rafter leg lengths;

• the type of wood used in construction;

• distances between rafters (rafter pitch).

You can determine the cross-section of the beam for the rafters, knowing the distance between the rafters and the length of the rafters using the data below.

Rafter cross-section - table

Advice. The larger the installation pitch of the rafters, the greater the load on one rafter pair. This means that the cross-section of the rafters needs to be increased.

Dimensions of lumber (timbers and boards) for a gable rafter system:

• thickness (section) of the Mauerlat - 10x10 or 15x15 cm;

• the thickness of the rafter leg and tie is 10x15 or 10x20 cm. Sometimes a beam of 5x15 or 5x20 cm is used;

• run and strut - 5x15 or 5x20. Depending on the width of the foot;

• stand - 10x10 or 10x15;

• bench - 5x10 or 5x15 (depending on the width of the rack);

• thickness (section) of the roof sheathing - 2x10, 2.5x15 (depending on the roofing material).

Types of gable roof rafter system

For the roof structure under consideration, there are 2 options: layered and hanging rafters.

Let's consider each type in detail in order to make an informed choice.

Hanging rafters

They are used for roof widths of no more than 6 lm. Installation of hanging rafters is carried out by attaching the legs to the load-bearing wall and the ridge girder. The design of hanging rafters is special in that the rafter legs are under the influence of a bursting force. Hanging rafters with a tightening installed between the legs, reduce its influence. The tie in the rafter system can be wooden or metal. Often the puffs are placed at the bottom, then they play a role load-bearing beams. It is important to ensure reliable fastening tightening on the rafter leg. Because a bursting force is also transmitted to it.

Advice.
The higher the tightening is located, the greater strength it should have.
If the tightening is not installed, the load-bearing walls may simply “move apart” from the pressure created by the rafter system.

Layered rafters

They are used for arranging roofs of any size. The design of layered rafters provides for the presence of a beam and a stand. The bench lying parallel to the Mauerlat takes on part of the load. Thus, the rafter legs are, as it were, inclined towards each other and supported by a stand. The rafter legs of the layered system work only in bending. And the ease of installation also tips the scales in their favor. The only drawback is the presence of a stand.

Combined

Due to the fact that modern roofs are distinguished by a wide variety of shapes and complexity of configurations, a combined type of rafter system is used.

After choosing the type of rafter system, you can accurately calculate the amount of materials. Write down the calculation results. At the same time, professionals recommend drawing up drawings for each roof element.

Installation of a gable roof rafter system

After the gable roof rafters have been calculated, installation can begin. We will divide the process into stages and give a description of each of them. It will turn out to be unique step-by-step instruction, containing additional information for each stage.

1. Attaching the Mauerlat to the wall

The beam is installed along the length of the wall on which the rafters will rest.

In log houses, the role of the mauerlat is played by the upper crown. In buildings built from porous material (aerated concrete, foam concrete) or brick, the Mauerlat is installed along the entire length of the load-bearing wall. In other cases, it can be installed between the rafter legs.

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Since the length of the Mauerlat exceeds standard sizes lumber, it has to be spliced.

The connection of the Mauerlat to each other is done as shown in the figure.

How to connect the Mauerlat?

The beams are cut only at an angle of 90°. Connections are made using bolts. Nails, wire, wooden dowels are not used.

How to attach the Mauerlat?

The Mauerlat is installed at the top of the wall. The installation technology provides several ways to attach the Mauerlat:

• strictly in the center of the load-bearing wall;
• with a shift to one side.

Advice.
The Mauerlat cannot be placed closer than 5 cm to the outer edge of the wall.

To protect the timber for the mauerlat from damage, it is laid on a layer waterproofing material, which most often is ordinary roofing felt.

Reliability of Mauerlat fastening important aspect construction. This is due to the fact that the roof slope is like a sail. That is, it experiences strong wind load. Therefore, the Mauerlat must be firmly fixed to the wall.

Methods for attaching the Mauerlat to the wall and rafters

Anchor bolts. Ideal for monolithic structures.

Wooden dowels. Used for log houses and beams. But, they are always used with additional fasteners.

Staples.

Stud or fittings. It is used if the cottage is built from porous materials (aerated concrete, foam concrete).

Sliding mount (hinge). Tying in this way allows for the displacement of the rafter legs when the house shrinks.

Annealed wire (knitting, steel). Used as an additional mount in most cases.

2. Manufacturing of trusses or pairs

Installation is carried out in two ways:

• installation of beams directly on the roof. It is not used often, since it is problematic to carry out all the work, measurements, and trimming at height. But it allows you to completely do the installation yourself;

• assembly on the ground. Those., individual elements(triangles or pairs) for the rafter system can be assembled at the bottom and then raised to the roof. The advantage of such a system is faster performance of high-altitude work. The disadvantage is that the weight assembled structure roof truss can be significant. To lift it you will need special equipment.

Advice. Before assembling the rafter legs, you need to apply markings. It is very convenient to use templates for these purposes. The rafter pairs assembled according to the template will be absolutely identical. To make a template, you need to take two boards, the length of each of which is equal to the length of one rafter, and connect them together.

3. Installation of rafter legs

The assembled pairs rise to the top and are installed on the Mauerlat. To do this, you need to make a gash at the bottom of the rafter legs.

Advice. Since the slots on the Mauerlat will weaken it, you can only make cuts on the rafter leg. To ensure that the cut is uniform and fits tightly to the base, you need to use a template. It is cut out of plywood.

Methods of fastening the rafter leg are shown in the figure.

You need to start installing rafter pairs from opposite ends of the roof.

Advice. To correctly install the rafter legs, it is better to use temporary struts and spacers.

A string is stretched between the fixed pairs. It will simplify the installation of subsequent rafter pairs. It will also indicate the level of the ridge.

If the rafter system is mounted directly on the roof of the house, then after installing the two outer rafter legs, the ridge support is installed. Next, the halves of the rafter pair are attached to it.

It is worth noting that the opinions of professionals differ on this issue. Some advise using a staggered fastening pattern, which will allow the increasing load to be distributed more evenly on the walls and foundation. This order involves installing one rafter in a checkerboard pattern. After part of the rafter legs is installed, the missing parts of the pair are mounted. Others insist that it is necessary to mount each pair in a sequential manner. Depending on the size of the structure and the configuration of the truss, the rafter legs are reinforced with supports and racks.

Nuance. Connect additional elements structures using cutting. It is preferable to fix them with construction staples.

If necessary, you can lengthen the rafter leg.

Methods for splicing rafter legs are shown in the photo.

Advice. The method by which the mauerlat is lengthened (cut at 90°) cannot be used in this case. This will weaken the rafter.

4. Installing the ridge of a gable roof

The roof ridge unit is made by connecting the rafter legs at the top.

Roof ridge structure:

• Method without using a support beam (see figure).

• Method using rafter beams. The beam is needed for large roofs. In the future, it can become a support for the rack.

• Method of laying on timber.

• More modern variety The method shown in the photo can be considered for making a ridge assembly.

• Cutting method.

After the rafter system is installed, we perform major fastening of all structural elements.

5. Installation of roof sheathing

The sheathing is installed in any case, and is designed for more convenient movement along the roof during work, as well as for fastening roofing material.

The sheathing pitch depends on the type of roofing material, for example:

• for metal tiles - 350 mm (the distance between the two lower boards of the sheathing should be 300 mm).
• for corrugated sheets and slate - 440 mm.
• under soft roof We lay a continuous sheathing.

Rafter system of a gable roof with an attic - video:

Conclusion

As you can see, despite its apparent simplicity, the installation of a gable roof rafter system contains many pitfalls. But, based on the recommendations given, you can easily build a reliable structure with your own hands.

The roof of the building protects it from cold, rain and wind. This is the same important element like exterior walls and foundations. The rafter system is load-bearing frame roofs. It takes on all the loads: from structures, from snow and wind. To avoid problems during operation, the roof structure of the house must be strong and reliable. Do-it-yourself installation of the rafter system should only be done after careful preparation and studying all the necessary information.

Roof and roofing

Before you start installing the roof of a private house, you need to distinguish between two concepts. Non-professionals are often confused, but builders clearly distinguish between the definitions of roof and roofing. The roof is the entire structure that separates the building from the street above. The roof structure of a private house includes rafters, all other load-bearing elements, thermal insulation material, roofing.

Rafters - load-bearing roof structures

The roof is the top part of the roof. She is also roofing covering . The installation of a roof requires careful selection of materials. After all, the reliability of waterproofing and comfort of living will depend on it.

System requirements

To properly install a rafter system with your own hands, you must take into account a certain set of rules. Without taking them into account, the structure will not be able to effectively resist negative impacts from outside.

First of all, it is worth considering strength. All elements must withstand the load without destruction. The design of the roof truss system requires preliminary calculation load-bearing structures according to the first limit state. It is he who checks the elements of the rafter system for strength.

The rafter system must be strong and rigid

The second requirement is rigidity. The maximum deflection is taken into account here. Roof structure wooden house or any other should not sag too much. The permissible deformations in the middle of the span are equal to the length of this span divided by 200. Before construction begins, the structure of the rafter system must be calculated according to the second group of limit states - for rigidity.

Do-it-yourself roof raftering is done taking into account that the structure is light in weight. Otherwise, the load on the walls and foundations increases greatly. It is for this reason that wood has become widespread as a base material. The wooden rafter system has sufficient strength, but weighs relatively little. Attention should be paid not only to the roof structure, but also to choosing the right roofing material. It shouldn't be too heavy. Ceramic tiles has lost its popularity not only because of the cost, but also because the roof of the house, its walls and foundations must be strengthened for it.

The weight of the roofing material for a wooden rafter structure should not be too large

Special requirements are presented to the quality of the material. Manufacturing wooden elements should be made only from good raw materials. It is worth considering the following recommendations:

• For the main elements, grade 1 or 2 wood is used. Grade 3 can only be used for sheathing and other small parts.
• It is recommended to make rafter structures for pitched roofs from coniferous species. They are more resistant to rot and other problems because they contain resin. With the same cross-section, the permissible span for hardwood there will be less.
• Before starting work, all elements must be treated with an antiseptic. This stage of preparation allows you to prevent many troubles in the future. You can also treat the wood with fire retardants if desired. This will increase fire resistance.
• It is better to purchase wood from the northern regions, which is harvested in winter. This material is of the highest quality.

Parts of the structure

The rafter system diagram includes many elements. To understand drawings and correctly perceive information, you need to know at least the basic ones. So, what is the roof made of?

Ridge, cornice and slopes - the main part of the roof

First of all, these are the ridge, cornice and slopes. These elements are the main parts. The ridge is the topmost part of the structure. Cornice or overhang - bottom. Slopes are inclined surfaces that are located between the ridge and the cornice.

The construction of a rafter system requires knowledge of load-bearing elements. These include:

• Mauerlat - timber that is laid along the edge of the walls of a building. The Mauerlat is needed to evenly transfer the load from the rafter legs, which are supported pointwise. Typically, timber with dimensions of 150x150 mm or 200x200 mm (for large buildings) is used for its manufacture.
• Rafter legs are inclined beams that transfer the load from the roof's own weight, snow and wind to the mauerlat. Such beams are usually installed from the ridge to the eaves. But when constructing a hip roof, elements appear that have only one of the specified points. They are supported on a ridge or on a cornice. Such details are called spigots. They usually have the same cross-section as the rafters. In fact, sprigs are rafter legs cut off on one side.
• Purlin - a beam on which roof elements rest. The purlin can be installed under the racks. Another option is a ridge girder (crossbar). The rafters rest on it at the top point. The cross-section of the purlin depends on its span, usually 200x200 mm.
• Sloping legs are only needed for hip roofs. They are diagonal rafters resting on the Mauerlat at the corners. The cross-section is assumed to be enlarged, usually 150x200 or 100x200 mm.
• Design wooden roof assumes the presence of puffs, struts and racks. They are designed to reduce the load on the main elements. When building a house with your own hands, it is important to remember that the racks cannot be rested on the floor span. Installation is only possible on underlying walls or on purlins spanned between walls. Such elements can be mounted on the ceiling only if it is designed for such a load and reinforced in the required area.
• The lathing is needed to make a base for the covering. For metal tiles and seam roofing, the lathing can be sparsely made of boards 32-40 mm thick. For bitumen shingles you need a solid base made of boards 25-32 mm thick or moisture-resistant plywood.
• In order to make the cornice overhang, install fillies. They become an extension of the rafters. The filly is attached to the rafters for a length of at least 1 m. The cross-section of the element is usually taken to be 50x100 mm.

Load-bearing elements hip roof

Another element of the rafter system is a truss. This is a one-piece structure that consists of rafters, tie rods, struts and racks, rigidly connected to each other. The truss has a triangular shape, and inside it is divided into several smaller triangles, which provides it with good stability.

Roof shapes

Roofs of pitched roofs are different forms. It is worth highlighting here:

Types of rafters

There are two designs:

• with layered rafters;
• with hanging rafters.

Installing a roof on a wooden house is only possible using the former. This is caused by two rules:

• hanging rafters must be firmly attached to the mauerlat;
• V wooden house The rafters must be hinged to the mauerlat.

These two statements contradict each other, so the rafter system of a wooden house can only contain layered elements.

Only layered rafters are installed in a wooden house

Layered beams are elements that rest on the Mauerlat at the lowest point and on the ridge girder at the top. This allows you to reduce the horizontal thrust that acts on the walls when the rafters try to move apart and take a horizontal position. Elements can be reinforced with racks or struts. In this case, contractions can be placed through one pair of legs.

Hanging tanks are supported only at the lowest point on the Mauerlat. At the top they just rest against each other. To prevent the system of wooden elements from moving apart, tightening must be done. It is better to install them on each pair of legs. This option is characterized by a strong thrust effect on the external walls, but it allows you to get more free space inside the attic.

Connections

Before you make a rafter system with your own hands, you need to carefully study the nodes. To build your home, you shouldn't save time or money. Only in this case the result will please you for many years.

Main rafter connection units

The fastening points of the roof truss system, which deserve special attention, are represented by the following:

• fastening the Mauerlat to the wall;
• fastening the rafters to the mauerlat;
• fastening the rafters at the top point;
• splicing rafters along the length.

Mauerlat to the wall

This node can be performed in several ways. The choice largely depends on the wall material. The construction of a building made of brick, block or concrete allows the use of the following methods:

• on the wire;
• on staples;
• on stiletto heels;
• on the anchor with the device monolithic belt along the edge of the wall.

Connecting the Mauerlat to the wall during construction brick buildings performed using anchors

Rafters to the mauerlat

Fastening is carried out in two ways:

• rigid for buildings made of brick, concrete or concrete blocks;
• hinged for wooden houses.

Rigid fastening can be with or without a notch. It is recommended to do the cutting on the rafters, and not on the mauerlat, since this weakens it. In both cases, the leg is rigidly fixed with nails, screws, staples or metal corners.

With rigid fastening, it is better to make a notch on the rafters and fix the structure with fasteners

For hinged fastening, a special part is used - a slide.. They allow the beam to move without obstacles when the walls of the building shrink.

The hinged connection allows the beam to move

Additionally, the rafter legs are attached to the wall. This is necessary to prevent the roof from being blown off by the wind. For fastening, use a twist of two wires with a diameter of 4 mm, fixed to the wall with an anchor or a ruff. In a wooden house, twisting can be replaced with staples. Fastening is carried out on each beam or through one.

At the ridge level

The layered elements rest on a ridge girder with a notch. Additionally, a board overlay is made on both sides. An overlay is also needed for hanging elements. It can be wooden or metal with holes for screws.

The ridge girder and rafters are connected using a notch

Splicing rafters

There are several methods for splicing roof rafters with your own hands. The choice between them largely depends on the experience of the master. The splice point is located at a distance of 0.15 span lengths from the support. In this case, not only the ridge girder and the Mauerlat are considered supports, but also the struts and racks.

Splicing rafters along the length

There are five ways:

• butt joint;
• oblique cut;
• overlap;
• compound legs;
• paired legs.

To build quality roof, you need to carefully study the technology, choose the right type of rafters and methods of connecting elements at important nodes. This is especially important when building a rafter system with your own hands.