Roof purlin installation. Do-it-yourself roof truss system: Instruction and Video. Installing a gable roof ridge

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

The gable roof frame, due to its design features, ideally combines ease of installation and maintenance with reliability and durability. These and many other parameters make the construction of a gable roof a practical and rational solution for private and commercial housing construction.

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

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

design variability;
simplicity in calculations;
natural flow of water;
the integrity of the design reduces the likelihood of leaks;
profitability;
preservation of the useful 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 primarily on its design.

There are several options for gable roofs (types, types):

The most common version of the roof device due to its simplicity and reliability. Due to the symmetry, a uniform distribution of loads on the load-bearing walls and the Mauerlat is achieved. The type and thickness of the insulation do not affect the choice of material.

The cross section of the beam makes it possible to provide a margin of bearing capacity. There is no possibility of bending the rafters. Supports and spacers can be placed almost anywhere.

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

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

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

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

The design of the gable roof truss system

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

The locations of the elements are shown in the photo.

Mauerlat. Designed to distribute the load from the truss system to the load-bearing walls of the building. For the arrangement of the Mauerlat, a beam of durable wood is selected. Preferably larch, pine, oak. The cross section of the beam depends on its type - solid or glued, as well as on the estimated age of the structure. The most popular sizes are 100x100, 150x150 mm.
Advice. For a metal truss system, the Mauerlat must also be metal. For example, a channel or an I-profile.

rafter leg. The main element of the system. For the manufacture of rafter legs, a durable beam or log is used. The legs connected from above form a farm.

The silhouette of the roof truss determines the appearance of the structure. Examples of farms in the photo.

Rafter parameters are important. They will be discussed below.

puff- connects the rafter legs and gives them rigidity.

Run:

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

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

Rafter rack- 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 sloping roof and the arrangement of one room in the 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 rack.

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

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

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

crate. It is intended for movement during construction works and fixing of roofing material. It is installed perpendicular to the rafter legs.

Advice. An important purpose of the crate is to redistribute the load from the roofing material to the truss system.

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

Advice. Be sure to add data on the passage of the ventilation shaft and chimney to the scheme of the gable roof truss system.

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

The choice of material for rafters

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

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

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

Calculation of the truss system of a gable roof

The calculation of material parameters is an important stage, so we present the calculation algorithm step by step.

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

1. Calculation of the load on the truss system

The load on the rafters can be of three types:

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

Advice. To make the margin of safety 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 the roofing material per 1 sq.m. roof area, did not exceed 50 kg.

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

In fact, the roof slope is like a sail and, given the wind load, the entire roof structure can be destroyed.

The calculation is carried out according to the formula: wind load is equal to the indicator for the region, multiplied by the correction factor. These indicators are contained in the SNiP "Loads and Impacts" and are determined not only by the region, but also by the location of the house. For example, a private house surrounded by high-rise buildings has fewer loads. A detached country house or cottage is experiencing increased wind loads.

2. Calculation of the snow load on the roof

The calculation of the roof 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, which falls on 1 sq.m. roof area (according to SNiP 2.01.07-85) is in the range of 80-320 kg / sq.m.

The coefficients showing the dependence on the slope angle are shown in the photo.

Nuance. With a slope angle of more than 60 ° snow load does not affect the calculation. Since the snow will quickly slide down and will not affect the strength of the timber.

Special loads. Accounting for such loads is carried out in places with high seismic activity, tornadoes, 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 bearing capacity of walls and foundations

It should be borne in mind that the roof has a significant weight that can harm the rest of the building.

Determination of the roof configuration:

simple symmetrical;
simple asymmetric;
broken line.

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

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

soft roof - 5-20°;
metal tile, slate, corrugated board, ondulin - 20-45 °.

It should be noted that increasing the angle increases the area of \u200b\u200bthe space under the roof, but also the amount of material. What affects the overall cost of work.

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

5. Calculation of the pitch of the rafters

The pitch of the rafters of a gable roof 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 number, you need to multiply 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 dwelling under the roof, the convenience of being in the attic, the consumption of material for the construction of the roof.

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

Parameter "c" is the hypotenuse of the triangle.

Advice. To the value obtained, you need to add 60-70 cm for sawing and taking the rafter leg out of the wall.

It should be noted that the maximum length of the beam is 6 r.m. Therefore, if necessary, the timber for the rafters can be spliced (building, joining, joining).

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

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

7. Calculation of the section of the rafters

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

load, we already wrote about it;

type of material used. For example, a log can withstand one load, a beam - another, a glued beam - a third;

rafter leg length;

type of wood used in construction;

distance 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 step of the rafters, the greater the load on one rafter pair. So, the cross section of the rafters needs to be increased.

Dimensions of lumber (beams and boards) for a gable truss system:

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

the thickness of the rafter leg and puffs 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 leg;

rack - 10x10 or 10x15;

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

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

Types of gable roof truss system

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

Consider each type in detail in order to make an informed choice.

hanging rafters

They are used with a roof width of not more than 6 r.m. The installation of hanging rafters is carried out by attaching the legs to the load-bearing wall and the ridge run. The design of hanging rafters is special in that the rafter legs are under the influence of a bursting force. Hanging rafters with a puff installed between the legs can reduce its influence. The puff in the truss system can be wooden or metal. Often puffs are placed at the bottom, then they play the role of load-bearing beams. It is important to ensure that the puff is securely fastened to the rafter leg. Because a bursting force is also transmitted to it.

Advice.
The higher the puff is located, the greater the strength it should have.
If the puff is not installed, the load-bearing walls can simply “disperse” from the pressure created by the truss system.

Rafters

They are used in the arrangement of roofs of any size. The design of the layered rafters provides for the presence of a bed and a rack. Lying lying parallel to the Mauerlat takes on part of the load. Thus, the rafter legs seem to be inclined towards each other and are supported by the rack. The rafter legs of the layered system work only for bending. And the ease of installation also tips the scales in their favor. The only downside is the stand.

Combined

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

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

Installation of a gable roof truss system

After the gable roof rafters are calculated, installation can begin. We break the process into stages and give a description of each of them. You will get a kind of step-by-step instruction containing additional information on 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 cabins, 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.

The material was prepared for the site www.site

Since the length of the mauerlat exceeds the standard dimensions of lumber, it has to be spliced.

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

How to connect the Mauerlat?

Washed down the bars is made only at an angle of 90 °. Connections are made using bolts. Nails, wire, wooden dowels are not used.

How to fix the Mauerlat?

The Mauerlat is installed on top of the wall. Mounting technology provides for several ways to mount the Mauerlat:

strictly in the center of the bearing wall;
offset to one side.

Advice.
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 of waterproofing material, which most often acts as an ordinary roofing material.

The reliability of fastening the Mauerlat is an important aspect of construction. This is due to the fact that the roof slope is like a sail. That is, it experiences a 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 construction.

Wooden dowels. Are used for fellings from a log and a bar. But, they are always used with additional fasteners.

Staples.

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

Sliding fastening (hinged). The bundle in this way allows you to ensure the displacement of the rafter legs when the house shrinks.

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

2. Production of roof trusses or pairs

Installation is carried out in two ways:

installation of bars directly on the roof. It is not used often, since it is problematic to perform all the work, measurements, trimming at a height. But it allows you to completely do the installation yourself;

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

Advice. Before assembling the rafter legs, you need to mark up. It is very convenient to use templates for this purpose. The truss pairs assembled according to the template will be exactly the same. 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 are interconnected.

3. Installation of rafter legs

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

Advice. Since the slots on the Mauerlat will weaken it, you can only cut down on the rafter leg. To wash down was the same and fit snugly to the base, you need to use a template. It is cut out of plywood.

Methods for attaching the rafter leg are shown in the figure.

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

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

A twine is stretched between the fixed pairs. It will simplify the installation of subsequent rafter pairs. And also, will indicate the level of the skate.

If the rafter system is mounted directly on the roof of the house, then after installing the two extreme rafter legs, the ridge support is installed. Further, half of the rafter pairs are attached to it.

It is worth noting that the opinions of professionals differ on this issue. Some advise using a staggered mounting order, which will evenly distribute the increasing load on the walls and foundation more evenly. This order involves the installation of 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 you need to do a consistent installation of each pair. Depending on the size of the structure and the configuration of the truss, the reinforcement of the rafter legs is carried out with props and racks.

Nuance. Additional structural elements are connected by cutting. It is preferable to fix them with building brackets.

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 (washed down at 90 °) cannot be used in this case. This will weaken the rafter.

4. Installing the gable roof ridge

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

Roof ridge device:

Method without using a support bar (see fig.).

A method using a rafter bar. Timber is needed for large roofs. In the future, it can become a support for the rack.

The method of laying on the beam.

A more modern version of the manufacture of the ridge knot can be considered the method shown in the photo.

Cutting method.

After the truss system is installed, we make a major fixing of all structural elements.

5. Mounting the roof sheathing

The crate is mounted in any case, and is designed for more convenient movement along the roof during work, as well as for fixing roofing material.

The step of the lathing depends on the type of roofing material, for example:

under the metal tile - 350 mm (the distance between the two lower boards of the crate should be 300 mm).
under a professional flooring and slate - 440 mm.
under the soft roof we lay a continuous crate.

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

Conclusion

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

21.02.2017 1 Comment

The truss system of a gable roof is a simple design that is available for a do-it-yourself device even for a novice developer. It is only necessary to make preliminary calculations, familiarize yourself with the details and stages of the construction of the roof, and calculate the materials needed for installation. When calculating, it should be taken into account that the bearing capacity of a gable roof depends on the influence of loads from wind, snow, and the weight of materials on it.

In order to make the process of building a gable roof truss system as easy as possible for you, below is a detailed step-by-step instruction for installing a truss system with your own hands.

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Requirements for building materials

For the installation of a truss system, the best option would be to use sawn timber from coniferous wood - pine, spruce or larch, grades I - III.

The material for the rafters is taken not lower than grade II, the mauerlat is made from boards or timber of grade II, for racks and girders material of grade II is taken, the lathing is made from grade II-III lumber, it depends on the roof. Crossbars, puffs are made of Grade I material. On linings, linings, material of grade III can be used.

Note! Lumber must be dry with a moisture content of not more than 20%. Before installation, it should be treated with flame retardants and antiseptics against fungal diseases.

You need to store lumber under a canopy, providing protection from the sun and moisture. Level the storage area, shift the lumber with linings for ventilation.

For installation, fasteners are required: ties, plates, studs, bolts with washers and nuts, self-tapping screws with EPDM gaskets, 2.8 mm thick, mounting tape, galvanized brackets.

Brackets are used when fastening the Mauerlat, they are fastened with nails or self-tapping screws.

KR corners serve to attach the rafters to the Mauerlat, prevent the rafters from moving.

All fixing material must be made of high quality material and protected against corrosion.

Tools for the construction of the truss system

To install the gable roof truss system, you will need the following set of tools:

tape measure, different lengths 5, 10, 20 meters;
markers, pencils;
cord, for stretching;
hammers, various purposes, nail puller;
scissors, for cutting;
roofing knife;
putty knife;
scotch;
hacksaws, electric saw, electric drill with various drills and nozzles;
screwdriver with nozzles;
markings, horizontal and vertical levels;
rails, rulers;
mounting foam;
safety belt and rope - for safe work.

Keep all roofing tools in a tool bag for safety.

Types of truss systems for a gable roof

sent rafters

They rely on the Mauerlat and racks installed on the inner wall, with a step equal to the rafters. To give rigidity during spans of 6 m, struts are additionally placed.

The scheme of the rafters of a gable roof

hanging rafters

If the building is small in width, it is possible to arrange a truss system when the rafters rest on the mauerlat or walls, without intermediate supports. The maximum span is 9 meters. Such roofs can sometimes be arranged without a Mauerlat. The rafters are installed on the wall, using gaskets, on the rafters in this embodiment, a bending moment acts.

To unload, put wooden or metal lining. They securely reinforce the corner. For hanging rafters of a larger span, a headstock and struts are installed. For hanging systems, the rafters are arranged with a larger section, and the lumber is chosen not lower than grade I II.

Scheme of hanging rafters of a gable roof

Calculation of the truss system

It is possible to determine the cross-section of a gable roof beam in the truss system by collecting all the loads acting on it: the weight of the coating, lathing, snow, wind pressure, precipitation.

Permanent loads can be determined by the weight of 1 m 2 of roofing, battens. It is important that the weight per 1 m 2 of the roof is in the range of 40-45 kg.

Variable loads from snow, wind are calculated according to the tabular values of SNiP normative documents, depending on the height of the building, temperature zone. The load from snow is equal to its weight multiplied by a coefficient depending on the slope of the slope. All these calculations are carried out during the project.

And if there is no project, and the roof is being erected on a small building? You need to look at the construction of a house in the neighborhood, which is being carried out according to the project, the roof area is the same as your building. The gable roof truss system will serve as a model.

Rafter beam dimensions

At the top point, a ridge is laid that connects the rafters. The height of the ridge depends on the slope of the roof. The slope is influenced by the choice of coating material. The minimum dimensions are:

for tiled roofs, slate 22 gr.;
for metal tiles - 14 gr.;
ondulin - 6 gr.;
corrugated board - 12 gr.

The optimal angle is 35-45 gr. slope, provides a quick discharge of water and snow. In regions with strong winds, the roofs are made flat and then the angle of inclination is within 20-45 degrees.

You can determine the height by the formula: H \u003d 1 / 2 Lpr * tgA. Where A is the angle of inclination, L is the width of the building.

The task is simplified when using a ready-made table. The coefficient depends on the width of the building and the angle of inclination. Multiply the coefficient by 1⁄2 of the width of the building.

The rafters are made from pine or spruce bars, with a section of 50 × 100 mm, 50 * 150 mm.

The size of the rafters depends on the pitch. The pitch of the rafters is smaller, a larger number is installed, the cross section will decrease. The distance between the rafters at a gable roof is in the range from 600 mm to 1800 mm, it all depends on the design of the roof and the materials used for its construction.

Table of rafter sizes, depending on the step of their installation

Length rafters, mm	Distance between rafters, mm	Rafter beam section size, mm
up to 3000	1200	80×100
up to 3000	1800	90×100
up to 4000	1000	80×160
up to 4000	1400	80×180
up to 4000	1800	90×180
up to 6000	1000	80×200
up to 6000	1400	100×200

The roof does not end at the level of the walls, it is extended 500 mm outwards. The rafter leg can protrude, or a board or bar is built up. In this case, moisture does not fall on the wall, the foundation is not poured.

Step-by-step installation of the design of the gable roof truss system

The gable roof truss system consists of the following elements:

Mauerlat.
Lie down.
Racks.
Rafter.
Struts.
Puffs.
Crate.

Mauerlat installation

Mauerlat fasteners to a monolithic reinforced concrete belt

Mauerlat evenly distributes the load on the walls of the building, its installation can be done in several ways:

fasten to the wall through a reinforced concrete belt with studs;
studs are inserted into the masonry;
a simple and common way for simple roofs, fastening with wire rod.

For him, take a bar with a section of 100 × 100 mm, 150 × 150 mm or 200 × 200 mm. Which section to choose depends on the size of the roof and its coverage. The Mauerlat is joined along the length, for this, make a 100 mm cut, 500 mm long, fold the bars and fasten with studs.

In the corners, the Mauerlat is tied with cuts to the floor of the beam, fastened with brackets or bolts. For wooden buildings, Mauerlat is the last crown. On brick walls, make a monolithic reinforced reinforced concrete belt, with a section of 400 × 300 mm. Align the pins with a thread of 12 mm in diameter along the belt, through 120 mm, for fastening.

Drill holes with a diameter of 12 mm in the Mauerlat, lay them so that the pins go into the holes. Tighten with nuts from above. Previously, we lay two layers of roofing material or roofing felt under the bar. On the outside of the wall, lay the Mauerlat with bricks. Laying the Mauerlat on a horizontally and vertically even base. It is necessary to check the horizontal level of the surface. Check diagonals. Align with pads if necessary.

Installation instructions for beds, racks, rafters, struts and puffs

Do-it-yourself do-it-yourself installation of a gable roof truss system is carried out in the following order:

To carry out the installation of the bed, with the sent rafters.
Mark the installation step of the rafter legs.
Prepare according to the size of the rack.
Install them, if necessary, unfasten them with spacers.
Lay a run. Check geometry. Install fastener.
Try on the first rafter leg, mark the cutting points.
Mark the points and install the rafters at the beginning and end of the roof, pull a cord between them in order to align the rest of the elements with it.
Having installed the rafter leg, we attach it first to the Mauerlat, then to the ridge run, to each other.
Screw every second leg with wire to the Mauerlat.

The fastening of the rafters to the Mauerlat is done with the help of notches, thrust corners and a hemmed support bar. Reinforce with nails or staples.

Methods for attaching rafters to the Mauerlat

Install the support posts on the beds or linings and linings. Lying is a beam 50 × 100 mm or 50 × 150 mm, laid on the middle wall along the lining of the roofing material. Place brick columns under the lining, 2 bricks high.

The rafter legs are connected to each other on the ridge. Consider the common connection nodes of the truss system:

They make cuts at one leg and washed down at the other. Insert one leg into the cut of the other and fasten with a bolt.
Install overlays, wooden or metal.
With the help of cuts in the run, they are fixed with nails or bolts.

Methods for connecting rafters on a ridge

For the stability of the roof to wind loads, puffs, struts and runs are installed. The tightening is a bar 100 × 150 mm, runs and struts are made from a bar 50 × 150 mm or 100 × 150 mm.

With the installation of contractions, the reliability of the rafter design increases. The sections of the beam are the same as the rafters. They are attached to the legs with bolts or nails. The bracing device adds rigidity to the structure. They are installed tightly, to the surface of the rafters.

Lumber has a standard length of 6 m. Rafters can be longer. Then you need to connect them. There are several connection methods:

Fasten by applying bars on both sides at the junction, connect them with nails in a checkerboard pattern.
Overlap, one part of the rafter to another, at a distance of 1 meter, fasten with nails in a variable order.
Run a cut obliquely, cut out part of the legs of the rafters, connect them, reinforcing them with bolts.

Lathing device

A crate is laid along the roof rafters. It serves to distribute the load from the roofing material, snow on the rafters. It plays the role of an air gap between the roof and the truss system.

The design of the crate depends on the accepted roofing material:

under the soft tiles, make the crate continuous, an anti-condensate film is laid on the rafters, pressed against the top with a counter rail, the crate is nailed onto it, then the OSB boards and the lining carpet, we lay the tiles on top.
under the roof of the corrugated board, the crate should be sparse. The step of the lathing depends on the brand of corrugated board, its thickness and the angle of the roof.
make a crate for a standard slate in increments of 500 mm from a bar 75 × 75 mm or 50 × 50, as well as boards from 30 × 100 mm. It is necessary to take into account the design features of the roof, with the final choice of a suitable option.

The lumber from which the crate is made is pine of the first or second grade. It is advisable to take a width of no more than 14 cm. With a width of more, the boards can warp and damage the roofing. The length of the nails should be three times the thickness of the crate. Lay the boards along the ridge. Set the first board of greater thickness to the height of the roofing.

To arrange a continuous crate along the slope of the roof.

With the first layer, lay a board along the ridge from it at a distance of 500-1000 mm next, and so on. With the second layer, lay the crate in the direction along the rafters. Arrange the joint between the boards only on the rafters in a run. The nail is sunk completely with the head into the pulp of the wood.

Cornice overhangs

Arranged to protect against precipitation, play an aesthetic role. Eaves overhangs suit tightly without gaps. The final stage in the construction of the roof.

Scheme of the device of the eaves overhang of a gable roof

Gable

The gable roof has two gables. They have the shape of a triangle, with the apex at the ridge and the sides coincide with the slopes of the roof. Gables support the rafters and enclose the attic space. Protect from wind and precipitation, give stability to the roof.

In wooden buildings, the pediment is made frame. In brick buildings, frame or brick. Gables made of brick or gas block are erected before the roofing device. They require very precise execution.

Frame gables fit into the finished opening when the truss system is already assembled.

The frame is made of bars or boards. The frame elements are connected on spikes or to the floor of a tree, all fastened with nails. They are sheathed by nailing boards, lining or siding, maintaining the color in the decoration of the facade of the building. For the device of a window opening, an additional frame is made under it according to the size of the window. If the attic is insulated, then the pediment also needs to be insulated. Insulation is laid in the middle of the frame. A mineral wool insulation with reduced flammability is used. From the outside, the frame is upholstered with a hydro-windproof film or a windproof membrane, from the inside, a vapor-tight film or a vapor-tight membrane is nailed under the finishing material.

In contact with

As you know, the truss system is the main supporting structure of the roof. It is she who "holds" the entire load of the roofing "pie", as well as all the loads from snow and wind. That is why its construction must be treated "responsibly". How to install such a system? How are roof trusses installed? What are the nuances to be considered here? This and other issues related to the truss system will be discussed in the article.

General concepts

Installation of rafters is one of the important stages in the construction of any roof. Most often, this work is entrusted to professionals, as it is quite difficult. But, if you have some experience in construction and carpentry, then you can do it yourself. But before proceeding with the installation of rafters, you should familiarize yourself with the roof structure itself.

This system includes the following components:

Stingrays. Their number depends on the type of roof. The most common option is a double-sided one. It is this main part of the roof that is supported by the rafters that you will lay.
Along the perimeter of all walls, from above is made. This element can be omitted if the house is built of wooden beams. The lower end of the rafters is attached to the Mauerlat. This element is necessary so that the weight of the entire system is evenly distributed on the walls.
Skate. This is the top of the roof. Here slopes and rafters converge. This element is present in any type of roof, except for a shed version.
Endova. It may not be included in all designs. The valley is present in cases where the slopes, and, accordingly, the rafters, form an incoming angle.
Overhang or cornice. This element is designed to ensure that precipitation flowing from the roof does not damage the walls and foundation. The overhang can be a direct continuation of the rafters or be their separate component. The cornice can recede from the walls to any distance acceptable to you, but it should not be less than thirty centimeters.
Roof. This part will directly protect your building from external influences. The roof may look like a kind of "pie". If in a, then you will have to install thermal insulation and other layers. If there is no attic, then it is enough to lay the roofing material and waterproofing.

The rafter system is the "backbone" of the entire roof. It is she who will carry all the loads from the roofing "pie" and other components. Therefore, the technology for installing rafters must be strictly observed. Proper installation will guarantee a long service life of the entire structure.

Material for rafters

During the construction of the roof, it is important to responsibly approach each stage. Installing rafters is "serious". But, if these elements are of poor quality, then little will depend on the correct installation. Rafters can quickly fail and then you cannot avoid serious repair work.

Before proceeding with the DIY installation, you should select the material for these basic elements of the entire roof system. What option can be used? Here, experts will offer the following:

You can install wood rafters with your own hands, using only a regular carpenter's kit. The most commonly used bars. In some cases, boards can also be used. The most important thing is that the material is of high quality. Do not use boards or bars that have been in use for a long time.

Preparation

Before putting the rafters, you should go through the preparatory stage. First of all, you should draw up a diagram. Without an accurate drawing, it is impossible to carry out the correct installation of the rafters. When drawing up a diagram, the following points should be considered:

What truss system will be used. There are two options - this is layered and. In each case, the installation of rafters is carried out according to its own rules. This must be taken into account.
Decide on the slope angle. Various parameters are taken into account here. First, the natural conditions in your area. The smaller the angle of inclination, the more snow accumulates. This reduces the wind load. With a large angle of inclination, the opposite is true. Secondly, recommendations from the manufacturer of the roofing material should also be taken into account.
Loads. Before drawing up a diagram, you should decide what forces will act on the entire structure. Based on this, all parameters of the rafters themselves and the frequency of their installation are calculated. Both variable and permanent loads are taken into account. The first includes atmospheric influences - these are precipitation and wind. Permanent loads include the weight of all roof components, including installed equipment, read more:.
The parameters of the rafters themselves. Here you need to calculate their length and cross section. These values \u200b\u200bwill depend both on the design features of the roof itself and on the loads that it must withstand, read also:.

After drawing up the scheme, you should prepare all the necessary materials and tools. Particular attention should be paid to the rafters themselves and other components of the truss system. Wood is a tricky material. Therefore, the installation of rafters should begin with their processing with various impregnations.

In addition, you need to carefully inspect each board or beam that will be used. If traces of decay or a large number of knots were noticed, then it is better not to use such material for installing rafters. You also need to pay attention to the moisture content of the wood. This parameter should not exceed ten percent.

In addition to wood for rafters, you need to prepare other materials and tools. First of all, stock up on fasteners. Installation of rafters is carried out using mainly nails. But besides this, metal brackets, corners and other devices can be used.

If we are talking about tools, then a regular carpenter's set will do just fine. Do-it-yourself installation of rafters is carried out using a saw, an ax, a planer, a drill and other tools. In addition, you should prepare devices for marking.

Methods for connecting rafters

Wood is excellent for processing. That is why, of course, in addition to all other advantages, it is chosen when building a roof. Due to the ease of processing, there are many ways to connect wooden elements. Before you start installing the rafters, you should know how they can be attached to each other, built up and connected to other components of the system.

You can use the following options to perform these tasks:

There are other methods on how to put rafters on the Mauerlat. Each particular option has its pros and cons. But in addition to the Mauerlat, the rafters must also be fixed to each other. This is done at the top of the roof ridge.

There are also many ways here. Installation can be carried out using bolts, plates, hinges or using a groove.

We carry out installation

And how to install rafters on the roof? What are the nuances and subtleties here? First of all, you should remember about safety. Laying rafters at high altitude is dangerous. It is best to make scaffolding before starting installation. But such a thing is very expensive and rarely used. Therefore, the installation of rafters on the roof should be carried out with personal protective equipment - these are mounting belts and so on.

In addition, doing everything with your own hands and alone is an almost impossible task. It will be impossible to lift and put the rafters alone. Wood weighs a lot. In addition, the structures themselves will be quite large. Therefore, you cannot do without an assistant.

The very technology of installing rafters on the roof is as follows:

The arrangement of a gable roof is considered a very practical and right decision in the construction of a residential or commercial building. This option combines the relative simplicity of execution and reliability, ease of maintenance and long service life. In this material, we will talk about how to install a gable roof truss system with your own hands, what are its varieties, and how to calculate the dimensions of its individual elements. Our step-by-step instructions will allow you to deal with any complications that may arise in the process.

A roof with two slopes has a whole list of advantages:

ease of calculation;
various versions;
saving materials;
the possibility of natural outflow of water;
low probability of water leakage due to the integrity of the structure;
the possibility of arranging an attic or attic;
reliability and long service life;
ease of preventive maintenance.

Varieties of gable roofs

Consider the main types of roofs with two slopes, the truss system in which will differ slightly in execution.

Symmetrical gable roof

This is the simplest gable roof, however, the most reliable and in demand. Symmetrical slopes allow you to distribute the load on the Mauerlat and load-bearing walls evenly. In this case, the type and thickness of the insulation layer do not affect the choice of roofing material. Thick beams of rafters have a sufficient margin of safety, so they will not sag. In addition, spacers can be installed at your discretion.

Among the disadvantages of this option, one can only note a too sharp angle of the slopes, which makes it difficult to use the attic floor and creates “deaf” zones that have no use.

Roof with two asymmetrical slopes

If the angle of inclination of the slopes is made more than 45º, some unused areas of space can be used. It will even be possible to equip a living space in the attic. However, some additional calculations will be required, as the load on the walls will become uneven.

Broken roof with external or internal break

This configuration makes it possible to place a spacious attic or attic under the roof. However, in this case, more complex engineering calculations will be required.

The design of rafters for arranging a roof with two slopes

The design of the gable roof truss system assumes the presence of such components:

Mauerlat. It is a durable bar made of oak, pine, larch or other strong wood, which is laid around the perimeter on the load-bearing walls of the building. The purpose of the Mauerlat is to evenly distribute the load. The cross section of the bars is chosen based on their structure - solid or glued, as well as on the age of the building. The most commonly used beams are 100 × 100 or 150 × 150 mm.
rafters. The whole structure is created from such elements (read also: ""). Connecting at the top point, two rafters form a farm. They are made from logs or durable bars.
puff. This part serves to grip the rafters and ensure their rigidity.
Runs. In those places where the rafter legs are joined, a ridge run is attached, on which the skate will subsequently be mounted. And with the help of side runs, the frame of the rafters is given additional strength. The expected load determines the size and number of such elements.
Rafter rack. This is a vertical beam that partially takes over the weight of the roof. If the gable roof scheme is simple, then one such beam is placed in the center. For a long span, three bars may be required - one in the center and two on the sides. If an asymmetrical roof is being erected, then the location of such a beam is determined by the length of the rafter legs. Under the rafters for a sloping roof, racks are placed on the sides to make room for movement. Beams are placed in the center and sides if there are two rooms.
Struts. These are rack supports. If significant winds and precipitation are expected in the winter, longitudinal as well as diagonal racks are installed.
Sill. A rack for rafters rests on it, and struts are also attached.

crate. The selected roofing material is attached to it, and you can also move along it during work. Fix the crate perpendicular to the rafters. Please note that the crate allows you to evenly distribute the mass of roofing material over the rafter system.

The installation scheme of the gable roof truss system will greatly facilitate all construction work. How such a roof scheme will look depends on the type of roof.

Please note that the material for the truss system must be of the highest quality, treated with flame retardant and antiseptic agents. There should be no knots or cracks on the beams for rafters, Mauerlat and racks. Only a small number of knots are allowed on the crate, firmly seated in the wood.

Calculation of frame elements for a gable roof

Laying Mauerlat on the walls

This element is mounted on a load-bearing wall along its entire length. If we are talking about a log house, then the upper crown can serve as a Mauerlat. For buildings made of aerated concrete or brick, a Mauerlat equal to the length of the wall will be required. Sometimes this detail can be laid between the rafters.

With a lack of material length for the Mauerlat, several pieces can be spliced. At the same time, the edges are sawn at 90º and joined with bolts - wire, dowels or nails are not suitable.

There are two ways to lay a Mauerlat on top of a load-bearing wall:

symmetrically in the center;
offset in the desired direction.

Mounting of the Mauerlat is carried out on a pre-laid waterproofing layer of roofing material. This will protect the wood from rotting.

It is worth taking a responsible attitude to the process of attaching the Mauerlat, since in strong winds it must withstand a particularly heavy load.

As fasteners for Mauerlat, you can use the following consumables:

Anchors, which are indispensable for monolithic materials.
Wooden dowels. These parts are used in houses made of timber and logs, although they require additional fastenings.
Staples.
Reinforcement or special studs. This option is preferable for buildings made of foam or aerated concrete.
Knitting or steel wire is an auxiliary fastener that is used almost always.

Assembly of trusses or trusses

Farm assembly can be done using one of the following methods:

Beams for rafters are assembled and mounted directly on the roof of the building. This process is quite laborious, since all measurements, trimming and coupling of the bars will have to be done at a height. However, you can do it on your own, without the involvement of technology.
Trusses or truss pairs can be fixed on the ground, and then the finished elements can be raised to the roof of the building. On the one hand, this simplifies the process of installing the rafters, and on the other hand, due to the large weight of the structure, lifting it up will require special equipment.

Please note that it is worth starting the assembly of truss pairs only after marking. And if you make a template in advance, for which you take two boards equal to the length of the rafters, and connect them together, then all pairs will turn out to be exactly the same.

Installation of rafters

After assembly and lifting to a height, the rafters of the gable roof of a wooden house are installed. To fix them on the Mauerlat, cuts are made at the bottom of the rafters. The first to install two trusses from opposite ends of the roof.

After that, a rope is pulled between the starting pairs, along which all the other truss trusses will be aligned and the ridge will be installed.

Now you can mount the remaining pairs in compliance with the calculated step between them. In cases where pairs are assembled directly on the roof, a ridge run is attached between the two end trusses. Subsequently, rafters are installed on it.

The order of installation of halves of rafters according to the opinions of professionals may differ. Some prefer to lay the bars in a checkerboard pattern so as not to overload the foundation and walls during work. Others tend to install pairs of rafters in series. Be that as it may, rafter legs may need props and racks - it all depends on the size of the roof and the shape of the trusses.

Skate mount

A ridge is an element that is formed by attaching rafters at the top point. As soon as all the details of the truss system for a gable roof are installed, it is necessary to perform a major fixing of all structural elements.

Lathing installation

The presence of lathing is mandatory in the construction of any roof. It not only supports the roofing material and allows it to be securely fastened, but also makes it possible to move along the roof during work.

The distance between the individual boards is chosen based on the type of roofing material:

soft roofing is laid on a continuous crate without gaps;
for a metal tile, a crate is needed with a step of 35 cm (between the two lower rows - 30 cm);
slate and corrugated board can be laid on the crate in increments of 44 cm.

Results

Thus, in order to assemble a truss system for a roof with two slopes, many nuances should be taken into account and any possible complications should be foreseen. We hope that our advice will help you cope with this difficult task and create a high-quality and durable roof for your home.

During the construction of private houses, the roof is most often made gable. There are reasons for this. First, it is reliable. Handles wind and snow loads well. The second - it is compatible with any roofing. The third is relatively inexpensive. The fourth is a simple design that is difficult to spoil. Fifth - it looks attractive. All this, and also the fact that a do-it-yourself gable roof is built without special knowledge, determines its popularity.

Do-it-yourself assembled gable roof ready for installation of roofing

Step-by-step installation of a gable roof

As you saw above, there are a lot of truss systems. Accordingly, when assembling each has its own characteristics, but in general the order is the same. It is necessary to say about the general step: pre-drying and processing of wood. This step is required if you bought fresh lumber, not dried.

The use of raw wood of natural moisture in the construction of the roof will lead to problems: the beams will bend, they will dry out, the geometry will change. All this will lead to the emergence of stress points and at the slightest sign of overload (a lot of snow, strong wind or rain), negative processes will begin. Their elimination is a complex and costly undertaking. Therefore, either buy dry wood (no more than 20%, ideally chamber drying 8-12%), or buy material a couple of months in advance, put it in ventilated piles. After that, treat with the necessary impregnations (from fungal attack and to reduce flammability) and only after that use it in the installation of the truss system.

Timber must be dried in ventilated stacks. To do this, they are laid in short pieces of boards. They are placed a meter from the edges and further through the meter. Spacers must be installed under the bottom

We will talk about the main stages of assembly, about how to make a gable roof with your own hands in this section.

Mauerlat

The assembly of the gable roof truss system begins with the installation of the Mauerlat. It must be set strictly horizontally, therefore, before starting installation, the horizontalness of the wall to which it is attached is carefully checked, if necessary, it is leveled with cement mortar. You can continue work after the solution gains 50% strength.

Depending on the system, this is a beam with a section of 150 * 150 mm or a board with dimensions of 50 * 150 mm. It is attached to the top row of masonry walls. If the house is wooden, its role is played by the upper crown. If the walls are made of light building blocks - foam concrete or aerated concrete and others - their rigidity is not enough to redistribute the load. In this case, a reinforced concrete belt is made over the last row of masonry, into which embedded fasteners are embedded - wire or studs. A bar or board is then mounted on them.

There are several ways to connect walls and Mauerlat:

In the masonry (in the reinforced concrete belt) a smooth rolled wire of large diameter is fixed (two ends stick up). Holes are then made in the board in the necessary places, into which the wire is threaded. She then twists and bends.
Studs with a diameter of at least 12 mm are immured in the wall. Under them, holes are made in the Mauerlat, a beam / board is placed) and tightened with nuts with wide washers.
Having aligned the beam or board along the outer or inner edge of the wall, take a drill with a diameter of 12 mm and make holes for the anchor bolts. They (the same diameter of 12 mm) are hammered to the very hat, then tightened with a key.

The distance between the studs (wire) should not be more than 120 cm. Cut-off waterproofing must be laid on the wall (belt) under the Mauerlat. It can be rolled roofing felt or waterproofing in two layers, it can be smeared with bituminous mastic.

Rafter installation

There are more than a dozen types of gable roof truss systems. First of all, you need to choose what yours will look like. Further, in order to make it easier to work, a template is made from thin boards for all cuts, cuts and other similar details. To do this, you may need to assemble the first form on the roof, and then make templates for the finished one.

The assembly order depends on the type of truss system. If the rafters are layered, they are installed gradually, assembling from the elements directly on the roof. In this case, it is convenient if the beams of the ceiling are laid and, if possible, the draft flooring of the attic or attic.

In systems with hanging rafters, a farm is assembled on the ground - a ready-made triangle of puffs and rafter legs with all the required struts, racks. The required number of farms is assembled at once. Then they are lifted to the roof, placed vertically there and attached to the Mauerlat.

On the one hand, this is convenient - it is easier to work on the ground, with a high assembly speed, the accuracy is high: one farm is not much different from the other, which simplifies the procedure. But it can be difficult to raise finished trusses, especially for large buildings. To make this easier, two inclined boards are installed, which at one end rest against the ground, and the other sticks out a little above the wall. Farms are brought closer to this “lift”, one by one they are installed below, ropes are tied and tightened along the boards to the roof. In the absence of a winch or crane, this is the most acceptable method.

The assembly of rafters requires certain knowledge: how and in what order to mount them, how to mark and make cuts. See the video for the assembly of one of the schemes with a headstock.

Assembly order of the truss system

Everything, the do-it-yourself gable roof is assembled and ready for installation of roofing material.

The process of installing the rafters itself raises enough questions, but there are many ways and it is impossible to tell about them all. See one of them in the video. The system is large and went up to the roof in parts, and there it was already assembled into a single structure. It is convenient for large houses.

Features of the installation of the truss system of a wooden house

The difference between wooden houses is that the log house shrinks, and this leads to a change in the geometry of the truss system. If the elements are fixed rigidly, the roof may fall apart. Therefore, the mounts are made floating. There are special sliding fasteners, which in this case attach the rafters to the upper crown and to the girders, if any (see photo).

In order for the rafter to move freely during shrinkage, its long part is fixed strictly parallel to its edge, and the support is placed strictly perpendicular. If necessary, a platform is cut out under it. Mark the mount so that the hook is in the lowest position or near it. They are mounted on special self-tapping screws that come with the kit (ordinary ones do not fit). If the installation is done on a log, so that the rafter leg does not slip along it, a semicircular hole is cut out in the lower part, on which it will rest.

Such fasteners are sold on any construction market, it is called "slippery". How to attach the slippery to the beam, see the video.

Video on assembling and installing a gable roof truss system

Building a gable roof with your own hands is not easy: there are a lot of subtleties and nuances, there are different ways of fastening, building up. Describing them in words is a thankless job. This is the case when it is better to see. Below is a selection of videos that you may find useful.

Video report on how a gable roof is made

The story of the owner of the house about the stages of construction. There are interesting technical points that may be useful.

Two types of rafter connection: rigid and sliding

Video about the two most problematic types of connections.

How to determine the angle of the rafters

Full video report on the assembly of the truss system

This movie is just under an hour long, but the entire process is shown from start to finish with plenty of detail. The roof is placed on, but when installed on buildings of a different type (except for wooden houses), there is no difference.