How to assemble roof rafters. Installation of the truss system - we do it like professionals. The procedure and rules for the installation of roof frames

truss system gable roof- a simple design, accessible 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 load bearing capacity gable roof depends on the influence on it of loads from wind, snow, weight of materials.

In order for the construction process truss system gable roof was given to you as easily as possible, below is a detailed step-by-step instruction for the installation of the truss system with their own hands.

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Requirements for building materials

For the device of the truss system the best option will use lumber from conifers wood - pine, spruce or larch, I - III grade.

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 crate is made from grade II-III lumber, it depends on the roof. Crossbars, puffs are made of Grade I material. On overlays, linings can be applied material III varieties.

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: couplers, 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, different 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

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

Scheme of layered rafters gable roof

hanging rafters

If the building is of small 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 required 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 roofing, crates. 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 from tabular values normative documents SNiP, 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. 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 less, it is installed large quantity, 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.

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:

1. Mauerlat.
2. Lie down.
3. Racks.
4. Rafter.
5. Struts.
6. Puffs.
7. 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 the brick walls, perform 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. FROM outer side walls, mauerlat lay 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:

1. To carry out the installation of the bed, with the sent rafters.
2. Mark the installation step of the rafter legs.
3. Prepare according to the size of the rack.
4. Install them, if necessary, unfasten them with spacers.
5. Lay a run. Check geometry. Install fastener.
6. Try on the first rafter leg, mark the cutting points.
7. 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.
8. Having installed the rafter leg, we attach it first to the Mauerlat, then to the ridge run, to each other.
9. 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. A bed is a beam 50 × 100 mm or 50 × 150 mm, laid on the middle wall along a roofing felt lining. 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:

1. 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.
2. Install overlays, wooden or metal.
3. 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 standard length 6 m. Rafters can be longer. Then you need to connect them. There are several connection methods:

1. Fasten by applying bars on both sides at the junction, connect them with nails in a checkerboard pattern.
2. Overlap, one part of the rafter to another, at a distance of 1 meter, fasten with nails in a variable order.
3. 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. Acting air gap between the roof and truss system.

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

• under soft tiles make the crate solid, 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 lining carpet, lay 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 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 roof deck. The length of the nails should be three times the thickness of the crate. Lay 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

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

Device diagram eaves overhang 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 windproof membrane, With inside a vapor-tight film or a vapor-tight membrane is nailed under the finishing material.

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Is it time to install the roof? The very first thing you need to do is the installation of the truss system. This work is very important and difficult, and therefore it is necessary to carefully read our advice.

A bit of theory - what you need to know about the truss system?

First of all, you need to talk about the types of truss systems and their characteristics. So, this system consists of the following elements:

• rafter legs;
• racks and vertical supports;
• struts;
• puffs - an element that connects the rafter legs.

You should also distinguish between rafters by type. Rafter systems are divided into:

• Layered. They should be used if the building has internal partitions or other supports. In this case, the "legs" of the structure must rest on both the outer walls and the inner ones.
• Hanging - in which the "legs" of the structure rest only on the outer walls. Distinctive feature of such a design is that for its design it is necessary to tighten due to high expansion loads.

Several important technical characteristics

When choosing a method for installing rafters, it is necessary to evaluate the complexity of the work and the weight future design. If the assembled product is lightweight or you can bring special lifting equipment to the site, then it is best to assemble the rafters on the ground, and then lift them to the roof of the building, where you can do all the other work. If the structure is characterized by a large weight, then it will have to be assembled directly on the roof - this is easier and safer.

It is very important to correctly connect the upper parts of the rafters. This work can be done in several ways. First of all, end-to-end, when cuts are made at the required angle on opposite rafter legs. Next, the rafters need to be docked along the ends obtained and secured to several nails. For a more secure connection, secure the products with a metal strap.

It is possible to fasten the rafter legs with an overlap - in this case, the structural elements are in contact with each other by planes. If you are going to make a rafter system in a house with fronts that are made of logs, then the rafters must be placed on the walls using the sliding fastener method. Thanks to this, you will be able to avoid deformation of the roof in case of shrinkage of the house.

If you decide to use this method, then you need to consider that it is quite difficult to do it yourself. Fasteners are made as follows: the “legs” of the rafters must be placed with a gap, fastening them together using a specialized movable metal element. Now we proceed to the direct construction of the truss system with our own hands.

Mauerlat - what is it and why?

The construction of the rafter system must begin with the installation of a Mauerlat - these are the foundations for the future design. Mauerlat is a log or timber, which is attached around the entire perimeter external walls. Undoubtedly, it is possible to make a structure without a Mauerlat, but it will be quite difficult and even risky to build such a structure with your own hands. It is very important to follow all the recommendations exactly so that the base for the truss system performs its functions 100%.

Important Tips:

• Before laying the mauerlat, the walls must be insulated with a suitable waterproof material. To save money, you can put several layers of roofing material.
• Installation of logs is carried out on a reinforced belt with a small indent from the edges of the walls.
• It is best to choose logs of antiseptic wood with a section of 10 * 15 cm.

For the convenience of doing work with your own hands, the bars must first be laid out from one front to the other along the entire length of the wall. After that, you can take measurements: lay out the bars according to the level, watching the evenness of the distance between them. Next, you can attach the bars to the walls. As we have already said, it is preferable to carry out installation on a reinforced belt, using anchor bolts- it is better to fix them when pouring reinforced belt. Also do not forget to drill holes in the beam itself.

Important: if you want to achieve a perfectly even position of the bolts, before pouring the “belt”, attach the board to the bolts and give the fasteners a vertical position using a square.

We put the base prepared with our own hands on stands consisting of planks, after which we carefully lower the bars onto the bolts, each time taking out a plank. At the end, we wind the washer to the bolt. Now it's time to learn how to make a truss system with your own hands.

Do-it-yourself installation of a truss system

We have already talked about the installation of the Mauerlat. Now it's time to move on to the main point of installing the truss system - this is the installation of floor beams and a ridge beam. But first things first. Floor beams - beams with a section of 20 * 10 or 15 * 10 cm. The length of the products should be such that, when laid on the walls, the beams form an extension that will correspond to the width of the eaves.

If to speak in simple terms, the bars should go beyond the walls at a certain distance. The bars are installed in one direction, leaving an equal distance between them.

To ensure that there are no errors during the execution of work, a clear sequence of actions should be followed:

• We mount the boards with our own hands, retreating from the edge of the walls by an average of half a meter.
• We stretch the cord between the bars - it will serve as a kind of "beacon" for the installation of the following beams.
• The distance between the "legs" of the structure must be chosen based on the section of the rafters. So, if you decide to choose "floor" boards, 5 * 15 cm in size, then the step should be about 60 cm. It is worth noting that this will greatly simplify everything further work. And all due to the fact that the width is most often 60 cm, which means that nothing will need to be trimmed.
• We proceed to the installation of transverse bars, which in one part should be in contact with the extreme beam, and the second - go beyond the walls. The gap between such jumpers should be about 1 m.
• We attract the beams to the base (Mauerlat) with the help of nails, you can also use self-tapping screws and steel corners(for reliability).

To make it as convenient as possible for you to carry out work during the construction of the truss system with your own hands, lay ordinary boards on the beams.

Now it's time to talk about installing a ridge beam. This stage consists of several steps:

• Installation of auxiliary racks, which are U-shaped struts made of wood. Professional experts advise that the height of the spacers be equal to the height of the first floor.
• We assemble racks at opposite ends of the structure and put intermediate beams, maintaining a step of 2.5 meters.
• After mounting the racks, we lay the ridge beam on top ( wooden plank with a section of 5 * 20 cm). Fix the structure with self-tapping screws.

Since the rafters must have the same length, it is advisable to make a template in advance to determine the length. To do this, we take one board measuring 2.5 * 15 cm, apply it to the beam and to the ridge, and put marks at the points of contact and saw off the unnecessary part - you can make blanks using this template. True, it is worth noting that not everyone can achieve perfect evenness, and therefore get ready for the fact that during the installation process you will have to use the saw more than once.

If you neglect this advice, then the skate may bend, which may make the design not so reliable.

After you have installed the truss system, you need to make waterproofing, create a crate and cover the structure with roofing material. Now you know how to assemble the truss system - the roof is almost ready. We hope our tips will help even you to do the work yourself.

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 options performance;
• 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 attic space 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 be somewhat different 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. AT 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 along the perimeter on the 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, fasten ridge run, 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 broken 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 winter period, install longitudinal, as well as diagonal racks.
• 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 antiseptics. 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 it's about 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, because when strong wind 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, which is almost always used.

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 to 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 rafters, and on the other hand, due to heavy weight construction, its rise to the top will require special equipment.

Please note that start assembly rafter pairs stands only after marking. And if you make a template in advance, for which you take two boards, equal to the length rafters, and connect them together, then all pairs will turn out exactly the same.

Installation of rafters

After assembly and lifting to a height, the installation of gable roof rafters is carried out wooden house. To fix them on the Mauerlat, cuts are made at the bottom of the rafters. First install two farms with opposite ends roofs.

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 lean towards sequential installation a pair of rafters. 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 gable roof will be installed, it is necessary to perform a capital 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 roof is laid on solid 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. We hope that our advice will help you cope with this difficult task and create a high-quality and durable roof for your home.

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 Effect design features perfectly combines ease of installation 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 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 step-by-step instructions 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 usable area an 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. because of sharp corners there are "blind" zones that are unusable.

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 rafter roof differs from the broken line, 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 requires 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.

Silhouette roof truss defines appearance buildings. 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 on attic loft- 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. Designed for movement during construction works and fixing 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 device to the gable roof truss system diagram ventilation shaft and chimney.

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 quality wood no damage or 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

Calculation of material parameters milestone, therefore, 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 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. Valid in different periods and with different strengths. These 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, on a private house, surrounded by high-rise buildings, there are fewer loads. Standing separately Vacation home or cottage experience 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:

Complete snow load equals 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.

How harder shape roofs, 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 influences total cost works.

Nuance. Minimum Angle slope 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.

Rafter length for attic roof 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 is worth noting that maximum length timber - 6 m.p. 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. How more step installation of rafters, the greater the load falls 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. Installation of hanging rafters is carried out by attaching the legs to bearing wall and skating. 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, allow you to reduce its influence. The puff in the truss system can be wooden or metal. Often puffs are placed at the bottom, then they play a role 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 characterized by a wide variety of shapes and complex configurations, it is used combined view rafter system.

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 of 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 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 beam for the Mauerlat from damage, it is laid on a layer waterproofing material, which most often acts as an ordinary roofing material.

Mauerlat fastening reliability important aspect 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). It is used as an additional fastening 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. Those., 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. The downside is that the weight assembled structure roof truss 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 struts.

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. Connect additional elements structures with 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.

• More modern variety manufacturing a 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 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 robust design with your own hands.

Roof installation is difficult technological process, which includes the stages of designing, assembling the frame, laying the roofing material and installing auxiliary elements. Although it is not easy to construct a roof correctly, to reduce the cost roofing works, if you have initial building skills and tools, you can make them yourself. In this article, we will describe in detail the sequence of actions necessary to independently install the roof truss system of a private house.

The truss frame of the roof is a set of wooden elements that form a kind of "skeleton" of the structure, supporting the roof slopes, giving them the necessary shape. If desired, the truss system can be made by hand, the main thing is to correctly calculate the loads and determine the composition of the structure. The functions of the roof frame are:

1. Roof slope support. The rafter legs give the surface of the roof slopes the slope necessary to effectively remove melted or rainwater, snow masses descended on their own.
2. Roof weight distribution. Properly calculated frame design evenly distributes weight roofing cake on load-bearing walls and the foundation of the structure, preventing deformation, subsidence of supports.
3. Place for fixing roofing material. Those who have at least once covered the roof with their own hands know that the frame crate serves as the basis for fixing the waterproofing coating.

Note! The truss frame is made of wood or galvanized metal. The cost of roofing, the service life and the bearing capacity of the roof depend on the choice of material. Experienced craftsmen believe: if the length of the slope does not exceed 6 meters, it is much more rational to make these elements from wood.

Create a project

Before you make the rafters for the roof of a private house with your own hands, you need to create a working design project that takes into account the climatic conditions in the area where the construction is taking place, the way the attic space is used, and the type of roofing. All these factors are taken into account in the calculation of loads that affect the roof frame. To determine the required bearing capacity and create a roof project, it is necessary to determine:

• The total load on the rafters. For this permanent loads(the weight of the rafter system itself, insulation, roofing material and waterproofing) is summed up with temporary loads (snow, wind and natural loads). Total weight roofing cake when using thermal insulation can reach up to 700 kg.
• Roof ridge height. This indicator is calculated based on the desired slope of the slopes and the width of the structure to be covered. The way the attic is used also affects the height of the ridge: if it is equipped with residential attic, the ridge should be located at least 250 cm from the ceiling.
• Slope slope. The angle of inclination of the roof slopes is calculated as the quotient of the height of the ridge and half of the base of the roof. This factor depends on climatic conditions in the region of construction, as well as the characteristics of the roofing material.

Important! The result of calculating the total loads, the height of the ridge and the slope of the slopes is correctly formatted, detailed diagram roof frame, which will facilitate the manufacture of the structure with your own hands, as well as reduce the risk of errors.

Material selection and preparation

To make a strong and durable truss frame for the roof of a private house, wood is used. hard rock or metal profile. The final cost, weight, service life and bearing capacity of the finished structure depend on the choice of material. For DIY work experienced craftsmen recommended to choose wood. In order for the rafters to serve for a long time, it is necessary to check the compliance of the lumber with the standard:

1. The moisture content of lumber used to make do-it-yourself rafters should not exceed 19-21%. Wet wood in the process of drying can crack, warp, which causes deformations and distortions in the roof.
2. The tree must be in a healthy state. That is, it must have light color, characteristic of the breed, do not have foci of decay, mold, browning or traces of pest activity.
3. For the manufacture of rafters, it is recommended to choose straight, even boards without a large number knots, as they reduce the strength of the supports.

Please note that the wooden truss frame lasts for a long time, before starting work on assembling the structure with their own hands, they will process the components with a deep penetration antiseptic, and to reduce firefighters, they are impregnated with a fire blocking compound.

Mauerlat bookmark

The installation of the truss system of a low-rise building begins with the laying of the Mauerlat. These terms refer to a support beam that is mounted on top harness load-bearing walls where the roof slope rests on them. The number of Mauerlat bars involved in the design always coincides with the number of slopes. Mauerlat is made from thick wooden beam 10-15 cm thick. The laying of this frame element is carried out in accordance with the following rules:

• Mauerlat is mounted only if the house box is made of brick, concrete, gas silicate, foam block. AT wooden buildings the role of Mauerlat is played upper crowns log house, firmly fixed with metal staples or dowels.
• Some types of layered truss systems do not provide for the installation of a power plate, since they do not exert a bursting load on the walls of the structure.
• Strong waterproofing is always laid between the wall of the house and the Mauerlat to prevent condensation from settling or wood rotting. For these purposes, use glassine, roofing felt or roofing felt.
• It is not allowed to perform a tie-in under the rafter legs in the Mauerlat, since each violation of the integrity reduces the strength of the timber.
• The Mauerlat beam is fastened with studs embedded in the wall of the house, or with long anchor bolts.

Do not forget that before installation, it is advisable to treat the Mauerlat with a deep penetration antiseptic to prevent wood decay, and also impregnate it with a fire retardant to protect the roof frame from fire.

Assembly technology

The degree of complexity and sequence of assembling the roof truss frame depends primarily on the design and type of rafters. To do the installation yourself, it is better to choose simpler gable structures. If load-bearing walls are provided inside the house, then a layered truss system can be used. The assembly of the frame takes place in several stages:

1. Bookmark Mauerlat and bed. At this stage, it is important to firmly fix the support bars along the load-bearing walls with metal studs or anchors.
2. Vertical racks are installed on a bed laid on an internal load-bearing wall in increments of 1.2-1.5 meters. To keep them upright, temporary supports are installed.
3. A ridge run is laid on top of the racks. It pulls together the vertical supports and serve as the basis for mounting the rafter legs.
4. Mount the rafter legs. One end of the rafter is attached to the Mauerlat, and the other to the ridge run.
5. A crate is nailed perpendicular to the rafters, on which the roofing is laid.

Remember to cover wooden house with your own hands is possible only after the complete shrinkage of the box. To compensate for the change in the geometry of the roof, movable fasteners are used that adapt to the size of the house.

Video instruction