How to make a roof frame correctly. Do-it-yourself rafter system for a gable roof: a review of hanging and layered structures

Construction of the roof is one of the most important stages in the construction of a house. The rafter part of the roof requires special attention, both at the design stage and at the stage of direct assembly. Before you begin installing the roof truss system, you will have to understand all the intricacies of the issue. Calculations are best left to professionals. Roof design takes into account great amount factors, these are wind and snow loads, the weight of the rafter system and roofing materials, geometry and technical specifications buildings.

There are specialized computer programs to calculate the optimal roof structure and calculate the amount of building materials required. Loads and impacts can be clarified in the SNiP 2.01.07-85 of the same name. Correction factors for individual regions are also given there. Almost all calculations must be increased by 10% to create a safety margin.

After the roof project is ready, the question arises about the correct installation of the roof rafters. Rafter trusses, in most cases, are a triangle. This is the most durable and cost-effective form. Rafters can be made of various materials: wood, metal or reinforced concrete.

A combination of different materials in one design is also allowed.

Rafter connections

Rafter trusses can be made independently, in accordance with the project, or ordered factory-made. Manufacturing to order does not impose restrictions on shape, volume and size. At the factory, both the entire rafter system and individual elements can be made for subsequent assembly directly on site. Industrial rafters are usually fastened using metal plates provided by the manufacturer. Rafters made independently are connected using a tongue-and-groove pattern and reinforced with nails, bolts, staples and clamps.

It must be taken into account that wooden elements rafter system should have a humidity of no higher than 20%. The material may shrink. Fastening roof rafters with nails or staples is only permissible for dry material. If the humidity percentage raises even the slightest doubt, you should choose bolting. They can be tightened over time, but the bolt holes weaken the strength of the rafters.

Design requirements

There are three main requirements for the design of the roof truss:

• Rigidity;
• Optimal weight;
• Quality of materials.

The requirement of rigidity directly relates to the joints and fastenings of all elements of the rafter system. As mentioned above, the rafter system is a system of triangular trusses installed parallel to each other. The triangular shape itself ensures the rigidity of the structure, but the rafters must be securely fastened relative to each other. Even the slightest movement can lead to disastrous consequences.

The requirement for optimal weight is fulfilled at the calculation stages. Total weight consists of all elements of the rafter system, hydro-steam and thermal insulation, roofing material. For example, natural tiles weigh 40-60 kg/m2, slate 10-14 kg/m2, bitumen shingles 6-8 kg/m2, and metal tiles 3.5-4.5 kg/m2. It is necessary to take into account how much weight the supporting walls of the building can withstand, taking into account constant and variable loads, because the effects of wind and the volume of snow will be added to the weight of the roof itself .

The quality of materials can be assessed according to several parameters. The type of wood should be 1-3 grades, with minimum quantity knots. Preference is given to coniferous species. Allowable board length coniferous species wood - 6.5 m, deciduous - 4.5. Mauerlat, pillows and purlins are made from hard hardwood.

Regardless of the cost and quality of materials, it is necessary to remember about waterproofing and treating all wooden elements with antiseptics and fire retardants.

Main parts of the rafter system design

Mauerlat- This is the base of the rafter system. Mauerlat evenly distributes the load on the external walls of the building.

Rafter leg– rigidly fixes the roof elements, is responsible for the angle of inclination of the slope. The appearance of the roof depends on the location of the rafter legs.

Run– fastens the rafter legs. The ridge purlin is located at the top, the side purlins are located on the side.

Puff– fastens the rafter legs at the bottom and prevents them from moving apart. Racks and struts provide additional rigidity to the rafter system.

Sill– located below, parallel to the ridge, and serves as the base and support for the posts and struts.

Lathing– arranged perpendicular to the rafter legs. Made from boards or bars. It is designed to transfer the load from the roofing material to the rafters and serve as the basis for the roofing material.

Part names

Roof ridge– the junction of two roof slopes. A continuous sheathing is placed along the ridge to strengthen this part of the structure.

fillies– arranged to organize an overhang.

Eaves- this is the distance from the wall of the house to the edge of the roof, intended to protect the house from excess rainfall on the walls.

Shapes of roofs and rafter systems

The shape of the roof is determined primarily by the geometry of the building. Different roof shapes can be combined in cases of complex structures.

Roof shapes

Roofs with a slope of 2.5 to 10 degrees are called flat. Not every building can be covered flat roof. The dimensions of the structure and variable loads characteristic of the construction region are important.

A pitched roof has the simplest rafter system design and a slope of 14 to 26 degrees. This roofing arrangement is ideal for extensions, verandas, and small structures in which one of the parallel walls is higher than the other.

Shed roof

A roof with two slopes has a more complex rafter system. The under-roof space can be either non-residential, attic, or attic, landscaped. Slope gable roof accepted in the range from 14 to 60 degrees. Gable roof rafter systems also differ in type. They can be hanging or layered, depending on the dimensions and geometry of the building.

Types of rafter systems

A hip roof is called a hip or half-hip roof. The slope of such a roof is allowed from 20 to 60 degrees, and the length of the covered span can be up to 12 meters. This design requires internal supports. The absence of gables significantly saves materials, but the design and installation of the rafter system requires more attention and means than in the case of a gable roof.

Sloping roofs in the lower tier can have a slope of up to 60 degrees, while the upper tier is usually flatter. Most often, a sloping roof is used to construct an attic. The permissible width of the house is up to 10 m.

This type of roof is called a sloping roof

Rafter systems can also vary in shape.

Various rafter systems

The shape of the rafter system is determined by the dimensions of the structure and the purpose of the under-roof space. Struts, racks and the rafters themselves can be used as decorative elements of the interior or attic.

Decorative elements

Types of rafter systems

Among other things, rafter systems also differ in type. They come hanging and layered. The choice of the type of rafter systems depends, like everything else in the roof, on the dimensions of the structure to be covered and the position of the load-bearing walls.

Hanging rafter system

Hanging rafters

A system with hanging rafters is chosen if the building has no internal load-bearing walls and the span does not exceed 6 meters. At the top, the rafters rest on each other, and at the bottom, the mauerlat acts as a support. Mauerlat is installed in a stone or brick house. In the case when the house is built using frame technology, the rafters are attached to the top frame. In log houses made of logs or timber - to the upper crown. The rafter expansion is reduced by tightening. Beam ties can serve as a ceiling for the upper floor.

The tightening is located at the very bottom. If it is placed higher, it is called a crossbar. In cases where the overlapped span is more than 6 meters, a system with hanging rafters is complemented support posts and braces. To organize the overhang, fillies are used. Experts recommend extending the rafters with a mare, even if it is possible to organize an overhang due to the rafter’s own length. Such an extension will allow the rafters to be supported on the Mauerlat with the entire available cross-sectional area. And the cross-section of the filly is chosen smaller than the cross-section of the rafters.

Layered rafter systems

Layered rafters

The main requirement for organizing a layered rafter system is the presence of an internal load-bearing wall or columns in the building. A roof with layered rafters can cover spans from 10 to 16 meters. The slope is selected based on the weather conditions of the area. In the upper part, the rafters rest on the ridge girder, in the lower part - on the mauerlat. Parallel ridge run a bench is arranged on which the racks rest. This allows you to do without puffs and crossbars. If the rafter leg does not have a strut or support, its length should not exceed 4.5 meters. Elements of the layered rafter system must have a thickness of at least 5 cm.

Regardless of what type of rafter system was designed, it is important:

• You cannot add nodes to the roof project on your own. Even if it seems that it would be more reliable. Shifting loads, even the slightest at first glance, can lead to distortion of the structure and possible collapse.
• The Mauerlat must be leveled in a horizontal plane relative to the walls of the house. Next, just as strictly horizontally, they connect it to the rafter leg. Vertical and horizontal levels are extremely important in order to prevent distortions.
• Rafter legs, racks and struts are placed strictly symmetrically.
• To prevent the rafters from rotting, ventilation is provided in the attics, and cracks in the attics.
• It is important to comply with the technology of insulation and vapor barrier of the roof.
• The joints between wooden elements and stone walls must be lined with waterproofing materials.
• When calculating the rafter system, it is important to take into account the location of the chimneys. This may affect the spacing of the rafters.

Connecting elements

A system of fastening elements using the cutting method is allowed, but it should be remembered that this is not the most economical way. Cutting requires quite large area sections, so that the structure as a whole does not lose its strength. This means that both the weight of the entire roof and the cost of building materials will be significantly higher. In this regard, most often the units are secured with dowels and bolts.

Fastening

Fastenings using perforated steel plates are often used. There are a huge number of such fasteners on sale, varying in shape and purpose. Perforated pads have a special coating that protects them from corrosion. They are secured with nails.

Rafter system

You need to decide on its type, which depends on geometric shape and roofing material. This article is devoted to the design and sequence of roof assembly using frame technology. Frame technology universal for roofs of any shape and involves the use of any roofing material. For design frame roof take into account the snow load of the area where construction is taking place and the size of the building being constructed.

The specialized literature contains many articles devoted to the shape of roofs, technical and economic aspects of construction. Our article will discuss in detail only the installation of a roof made of new material “ Shingles«.

So, what are the requirements for a roof assembled using frame technology?

Such a roof must ensure that the load (wind or snow) is transferred to the walls of the house, and it must also protect all the parts from which the frame of the house is made from precipitation (rain, snow, excess moisture). It is necessary to leave enough space under the roof to install insulation that will insulate attic space from warm rooms home, the attic must be well ventilated and ventilated, the roof itself and the roof frame must be well protected from the adverse effects of the warm part of the house (especially heat and moisture).

Basic requirements for the ceiling.

All further construction will depend on the correct calculation of the overlap. The construction of the roof frame begins with the ceiling. The parts of the floor are as follows: support beam, floor frame and flooring. The sheathing that is done on the ceiling is also the subfloor. The final finishing of the floor will be laid on it in the future. The figures given below apply only to a wooden frame in which the distance between the floor beams is not more than 600 mm, and the floor load is not more than 2.4 kPa.

So, the humidity of the boards should be no more than 19%. The deflection of the boards must have certain indicators - for a board 4.6 m long - no more than 12.7 mm (if the ceiling is covered with plasterboard) and 19 mm (if the ceiling is not covered with plasterboard). According to the standards, these are boards of such grades as selected, first or second with a thickness of 9.2 mm for the first case and boards of the third and fourth grade with a thickness of 1.4 mm for the second case. The ceiling is secured to the foundation using a support board, and between floors the ceiling is tied to the top frame of the walls. The support board and the basement floor frame must have a cross-section of 38x89 mm.

Basic rules for the construction and design of a frame roof.

The maximum free span should not exceed 12.2 meters.

The largest distance from truss to truss (or between rafters) should not exceed 600 mm.

If the roof is assembled according to a truss pattern, then the size of the main frame elements correlates with the width of the spans and the load of the snow layer. The rafters themselves come in the following types:

• free-standing;
• rafters that support the load from the attic ceiling (the frame of its floors).

In the future, for convenience, we will call them free rafters and loaded rafters. There are special tables that determine the size of the required rafter section. Also, parameters attic floor can be determined from tables. The boards from which rafters and ceiling beams are made must have a section size of 38x89 mm. If a heavy roof is used clay tiles, and the windows in the building are large attic, then it will be necessary to strengthen the roof frame or calculate the parameters as for loaded rafters. If the roof has a slope of less than 28 degrees (the full span is related to the rise as 1:4), then the calculation for loaded rafters is applied.

The table shows minimum values sheathing thickness, depending on the distances between rafters or trusses:

It is important to note that all the parts that make up the roof must be securely and firmly connected to each other. In the construction of an attic floor, it is necessary that the rafters and beams rest securely on the wall. A rafter beam, called a mauerlat, can also serve as a support. From above, the rafters come to the ridge board and are connected to each other there. The proportions of the ridge should be as follows: its width should not be less than the length of the rafter support; The dimensions of the ridge board section itself are 17.5x140 mm, no less. It is better if the ridge board is larger in size than the rafter boards. When fastening the rafters to the ridge board, they must not be allowed to move. There must be a right angle between the rafters and the ridge board, as well as between the rafters and the mauerlat.

In order to attach the rafters to the mauelat, it is necessary to make a cut in it. The length of the support itself must be at least 38 mm. If ridge and valley rafters are used, then the length of the support is 50 mm, the boards from which they are made are at least 38 mm thick.

Between shortened rafters (spikes) and ridge or valley rafters, an angle of 45 degrees must be maintained with respect to the floor plane.

It doesn’t hurt to remind you that a roof is protection exterior finishing walls from adverse weather influences, so the rafters should protrude beyond the walls by 400-500 mm, and for wooden walls this figure is even larger - 550 mm. The distance from the edge of the wall to all ends of the rafters should be the same. The free ends of the rafters are connected to each other using a special board called a roller. The connection of the roof bolster boards can only be at the end of the rafters. The bolster is made from boards with a minimum thickness of 17.5 mm, but usually the same boards are used as for the rafters.
If the roof slope is 1:3 or more, then the calculated roof span can be made smaller. This is achieved by using supports, yokes and additional supports for the ridge. Additional frame elements must be made from boards with a section size of no less than 38x89 mm.

If the roof slope is 1:4 or less, oblique struts are used. In such a roof, it is not superfluous to use additional walls to transfer the load from the rafters to the floor beams. In this case, it is necessary to install continuous struts under these walls between the floor beams. The maximum deflection of these beams when exposed to the calculated snow load should be 25 mm.

In the case when the beams from which the ceiling is made are not connected between opposite rafters, be sure to install additional ridge support (if the roof angle is 1:3 or less). If this angle is greater, such support is not necessary, provided that the joint at the bottom of the rafters is securely connected.

For fastening various additional systems and communications in the roof frame, cuts and holes are made. The parameters of the cuts (their sizes and position) meet the requirements for the floor frame.

The sheathing of the roof frame can be made of plywood, boards, chipboard and other materials. Their thickness depends on the distance left between the rafters. If sheet materials are used, their thickness should correspond to the support of the edges on the wooden roof frame. The sheet materials used in construction can significantly improve the appearance of the roof. In addition, they can strengthen the entire frame structure. Of course, when using such materials, it is important to follow all the basic rules for the construction of a frame roof. From many years of construction experience, the following are the most successful materials for lathing: fiberboard (especially grade P-3), DSiP, not sanded or having a phenol-formaldehyde base. In addition, DSiP has a higher fire resistance rating in relation to boards and plywood.

With a distance between the rafters of 300 mm, the thickness of the cladding is as follows: plywood - 7.5 mm; DSiP - 9.5 mm; board - 17 mm. At a distance of 400 mm, the thickness of the plywood is 7.5 mm (all edges with support) and 9.5 mm (between rafters without support), the thickness of DS&P is 9.5 mm (all edges with support) and 11.1 mm (between rafters without support), board thickness - 17 mm. With a distance between the rafters of 600 mm, the thickness of the plywood is 9.5 mm (all edges with support) and 12.5 mm (between the rafters without support), the thickness of the DS&P is 11.1 mm (all edges with support) and 12.7 mm (between rafters without support), board thickness - 19 mm. These are the minimum indicators.

The attic space, located between the insulation and the roof sheathing, must have ventilation holes. Good ventilation allows you to preserve all the properties of the insulation and prevent the adverse effects of moisture and heat on the premises themselves in the building, frame and roof.

Dimensions ventilation holes depend on the area of ​​the insulation carpet and must be at least 1/300 of the area of ​​the insulation on the attic floors. With a roof slope angle of 1:6 or less, the area of ​​the ventilation holes should be 1/150 of the insulation area. Half of the ventilation holes should be placed near the ridge, the other half in the soffit. The distribution of ventilation holes along the soffit should be uniform. A distance of at least 75 mm must be left between the insulation and the sheathing. If this rule is difficult to implement, then special screens are installed between the insulation and the sheathing.

The opening to the attic must be closed with a hatch and have a size of 500x700 mm (no less). The hatch should be located in such a place that there is a distance of more than 600 mm between it and the nearest rafters. The hatch needs to be insulated. Foam plastic (thickness 100-150 mm) is usually used as insulation material.

The roof itself on the roofs frame type are made from a wide variety of materials. In this article we will describe a material that is widely used in North America and is called "Shingles". Translated into Russian, this word means “shingles.” The basis of “Shingles” is different - wood, metal, etc. To reduce the cost of roofing in economy-class buildings, this material is used on a bitumen base, which has a coarse-grained bedding (such as roofing felt). Main advantages of this material are high technology, durability, aesthetic appearance. In Russia, “Shingles” is already widely represented in construction stores and is beginning to be manufactured in its own production facilities. This material can be used to cover roofs with a slope of 1:6 or more.

In special construction tables You can find information about the required number of nails for assembling rafters and floor beams. When forming connecting nodes, it is not necessary to create additional wind connections.

Now we will focus on the rafter diagram of the roof frame (its most important components).

There may be different distances between rafters and floor beams. They must connect at least 1.2 meters apart. The rafters and floor beams are connected using various nodes. Their other important function, in addition to connecting, is to provide the necessary space for laying insulation and creating space for free air circulation (attic ventilation).

Rafters and ceilings can rest either on walls or on a Mauerlat board, which is installed on the floor beams.

Here are the mandatory rules for installing the Mauerlat boards: the second Mauerlat board should stand in the same way as on the top frame of the walls, provided that there is a displacement of the rafter support towards the floor beams by more than 50 meters. The first Mauerlat board must be nailed (with two 82 mm nails) to each attic floor beam. Be sure to install the strapping board on the floor beams, especially if they are not directly connected to the rafters.

If the rafters and floor beams are located at equal distances, it is better to make a double connection unit. To do this, use a single Mauerlat board, and if the insulation is thick enough, additional support is placed on the top lining of the wall.

To connect each rafter to the ridge, at least three 82 mm nails are required reverse side and at least four 57 mm nails from the rafter side. The connection of the rafters and the yoke is carried out with three 76 mm nails. The position of the yoke must be strictly horizontal. The connection between the shortened rafter (spring) and the valley or ridge rafter should be made using two 82 mm nails.

The sheathing sheet material can be attached to the rafters in the same way as the sheathing of the floor frame. The sheets are laid with a gap of at least 2 mm. If necessary, you can install support for the edges of the sheathing sheets. Usually this is a board with a section size of 38x38 mm. The rules for attaching it are the same as for floor struts.

If the roof frame is made of trusses, then the same rules and regulations are taken into account as when installing floor beams.

For the manufacture of large roofs, especially those with only two slopes, as well as roofs that have a large unsupported overhang, it is better to use trusses. For the construction of multi-tongs and hip roofs perfect fit rafter diagram frame. Both design schemes can be combined in one building.

Long-span trusses may eliminate the need for a mid-load-bearing wall. In this way, houses have a so-called free internal layout.

To make the roof structure lighter, as well as to reduce its cost, it is necessary to reduce the cross-section of the boards that are used for rafters and elements reinforcing the frame. For these purposes, more than quality boards the best variety. Also, for these purposes, the distance between the rafters is reduced and the load from the rafters is transferred to the load-bearing walls using various connection units.

When developing the connection between the rafters and the ceiling, it is necessary to provide space for the insulation sufficient for its free ventilation. In addition, it is important to correctly calculate the distance between top part window opening and the horizontal surface of the soffit.

The covering material is selected taking into account a certain angle of inclination of the roof.

When designing, it is better to specify the roof slope angle in degrees. In this case, you will not need to calculate the dimensions of the ridge rise.

When installing a roof over attic room, it is better to calculate the characteristics of the rafters based on the strength characteristics. In this case, it will be possible to complete it later additional design, in which the insulation will be placed and sufficient ventilation will be ensured.

Boards for rafters must be selected taking into account the possibility of their further strengthening (if the attic will be used) with the help of yokes. It is strictly forbidden to transfer the load from the rafters to the floor beams, which are located freely in the span.

To give the roof a beautiful shape, designers strive to create the same slope for all surfaces. It is not always justified to use expensive, durable materials for roofing. It has long been calculated that even the most durable material requires periodic repair. Therefore, sometimes it is more profitable to completely replace inexpensive coating than constantly repairing the old one.

Recommendations for the correct assembly of the roof truss frame (basic techniques and rules).

As soon as the attic floor is installed, you can begin to install rafter frame roofs. What are the basic installation techniques?

1. The construction of the frame begins with the installation of a Mauerlat board to ensure an equal span along the entire length of the house. In the case of a multi-gable roof (this happens on houses with a complex plan), the Mauerlat is mounted simultaneously over all extensions. The joints of the boards must coincide with the floor beams. In the corners of the house, additional load on the walls of the house is transferred by ridge and valley rafters through additional supports under the Mauerlat board.

2. Rules for the location of spacer boards and floor beams. The rafters are located at the same distance as the pitch of the floor beams. Spacer boards must be nailed to each floor beam with two nails. If you move the Mauerlat board slightly relative to external wall, then you can change the span distance, but not more than 30-50 mm. This way you can adjust the span throughout the house to a single value. If the roof is multi-gable, then the span value is allowed to be different for each extension. In this case, each span will require its own calculation of the length of the rafters.

The proposed method of assembling and installing the roof frame has one very important advantage - all calculations and preliminary preparation individual parts can be produced on the ground. You only need to know the size of the spans from the outer edge of the Mauerlat board and the length of the roof itself, which is also measured from the Mauerlat.

The proposed project includes a given roof slope angle. The half span value has been calculated. Therefore, using the cosine of the roof slope angle, you can calculate the length of the rafters. Based on the type of wood, snow load and distance between the rafters, the tables can be used to determine the cross-sectional area of ​​the rafters. The next stage is making a rafter template from the straightest board. Also, using special tables depending on the length of the rafters on the angle of inclination of the roof, we make an oblique cut at the junction of the rafters and the ridge and make a notch with a wedge so that the rafter can be connected to the mauerlat.

Then you need to calculate how far the rafters will extend beyond the outer wall (be sure to not forget about the thickness exterior finishing walls according to the project - if the finishing is done with brick, then in the presence of an air gap this figure will be equal to 145 mm). Using a square, you need to mark and then make a cut parallel to the direction of the cut that connects to the ridge. So, the rafter template is ready. Using this template, rafters will be made for the gables and those rafters that are adjacent to the end part of the ridge board. To make a rafter template that rests on a ridge board, you need to reduce the main template by a distance equal to half ridge thickness.

Ridge length is defined as the length of the roof minus the full span. In order to correctly mark the ridge, the board is placed on the floor beams along the entire length of the roof. In this case, from each end to the edge of the roof there should be a distance equal to half the span. The markings are made along the wide part of the board. The position occupied by the floor beams is transferred to it. It is also necessary to note the position of the rafters along with the floor beams. To do this, use the same principle as for walls and ceilings.

If valley or ridge rafters are used, then the span when using a triangle should be not 30 cm, but 42.7 cm while maintaining the same amount of ridge lift. This is due to the fact that they are installed at a smaller angle than conventional rafters. The length of the ridge rafters is also easy to determine. It is taken into account that the unit of their length is a multiple of the span, like that of a conventional rafter. If ridge rafter when connected, it enters the point of intersection of the axis of the ridge board and the rafters, then its length is shortened by approximately 30 mm.

The length of the rafters (or shortened rafters) is calculated based on the given span and the distance between the rafters. If the roof has the same slope in all places, then the cut of the shortening rafter will always be 45 degrees. This cut is very easy to do using a hand electric saw. Using trinometric functions, the amount by which the next rafter will be shortened is calculated. There are special tables of these values ​​for distances between rafters of 400 and 600 mm.

When erecting a roof, the “first fiddle” in the entire structure is played by the roof frame. It is the frame that bears the main mechanical load, which means that the highest demands are placed on the strength, reliability and durability of the frame. Roofing material, insulation and waterproofing can be very different, but if the frame is built with flaws - good luck: such a roof will not last long.

Very often, the construction of a roof frame confuses novice craftsmen. However, if you look at it, there is nothing impossible in this task; you just need to choose one of the proposed ones and get down to business.

With the proper approach, correct calculation and good theoretical preparation, the frame part of the roof for small house can be built even alone.

At the same time, you will not only significantly save financial resources that would inevitably be spent on paying hired craftsmen, but you will also be able to control the process of constructing the frame.

And this, in turn, means that the design of your roof will not present you with unpleasant surprises at the most inopportune moment.

In this article we will tell you how to make a roof frame yourself, using only the most common tools and materials.

For example, we will take the frame of the most common gable roof type. But if you master this technology, then you can easily build roofs of other designs (hipped, pitched, pitched) - you just need to take into account the features of a particular design.

The first thing we need to decide on is the type of rafter system. Any rafter system consists of two rafter legs connected to each other at the top.

In the lower part, the legs are connected by a lower screed, which can also serve as the basis for the attic floor. However, there may be nuances in the structure of such a system.

The frame of the roof of a house can be built on the basis of two types of rafter systems: layered and hanging. Both layered and hanging rafter systems can be used in private construction.

How to choose a system for constructing a frame?

The choice of rafter system is determined mainly by the design features of the building itself. If the distance between the external load-bearing walls does not exceed 6 m, a hanging rafter system can be installed.

The peculiarity of this system is that the rafter legs rest only on the side walls of the house - and with a large building width, a rather dangerous sagging of the building rafters occurs under their own weight.

A more reliable layered system is used when the distance between external load-bearing walls exceeds 6 m, but in the room itself there is an internal bearing wall, located in the center of the building.

In this case, you can avoid sagging rafters by installing additional support.

Choosing materials for the frame

What do we need to independently build a gable roof frame?

The rafters - the key component of the frame - will be built from wood. To do this, we need to purchase a 50x150 mm edged board, as well as a 150x150 mm timber.

It is optimal if the wood is coniferous, harvested in the winter, and one from which the resin has not previously been drained (the resinous substances in the wood significantly extend its service life, acting as a natural antiseptic). The conditions in which the wood was stored before purchase and the degree to which it was dried are also very important.

When inspecting boards and beams, it is necessary to pay attention to possible wood defects: delamination, cracks, traces of damage from woodworms.

Materials on which these signs are found must be rejected - their use in the construction of a roof frame is unacceptable.

Note! Roof frames can be made not only from lumber, but also from metal channels or reinforced concrete structures. But in this case the roof turns out to be quite heavy, and we are talking about it self-construction no longer works.

In addition to the rafter legs, purlins and racks that make up the rafter system, the design of the roof frame includes an attic floor, as well as counter-lattice and sheathing.

If the attic space will be used for its intended purpose (i.e. as an attic or warehouse), then a 50x150 mm board is sufficient to construct the attic floor.

If attic space will act as an attic (i.e. living space), then the floor must be more durable: to lay it we will need a 150x150 mm beam, which is laid directly on the mauerlat. The use of such timber allows you to achieve sufficient strength from the attic floor.

For the sheathing and counter-lattice we use thinner timber. A square beam of 40x40 or 50x50 mm is quite suitable. Beams of this thickness are strong enough to support the weight of almost any roofing material.

When choosing beams for sheathing, you need to strictly monitor their straightness, because the slightest deviation from a straight line can significantly complicate roofing work.

Also, for the construction of lathing and counter-lattice, a perforated profile made of galvanized iron can be used.

In addition to materials for the construction of rafters, floors and sheathing, we will need:

• Threaded metal studs for attaching the Mauerlat (support beam)
• Brackets and brackets for attaching rafter legs to the Mauerlat
• Fastening elements (wood screws, studs with a diameter of 8 and 10 mm) for connecting the rafters to each other
• Galvanized nails

The set of tools required to build a roof frame is quite standard: you will need hammers of different sizes, a drill for drilling holes, a saw (or grinder) for cutting the rafters to size and giving them the desired shape, carpenter's ax, planes - in general, everything that is already very likely to be found in your tool cabinet.

Particular attention should be paid to the measuring tool, because without an accurate level, plumb line and tape measure, you are unlikely to be able to align the rafters exactly at a sufficiently large distance.

Frame wood protection

Before proceeding with the construction of the rafter system, it is necessary to provide all wooden parts of the roof frame with protection from fire and rot.

To do this, all parts of the rafters, ceilings and sheathing must be treated with two compounds:

• Antipyretic - a composition that reduces the flammability of wood and protects the wooden part of the roof frame from fire
• Antiseptic – a substance that kills bacteria and prevents the occurrence of putrefactive processes in the wood of rafters and ceilings.

Note! Some wood preservatives are quite toxic. Therefore, they should be applied only in a well-ventilated area or outdoors, and use products personal protection(glasses and respirator).

Protection of the roof frame is possible even after its construction. In this case, we treat the already installed structure with a fire-retardant and antibacterial composition, Special attention focusing on impregnation of wood at the joints of the beams of the rafter system.

So, the type of rafter system has been selected, the materials have been purchased and processed protective composition. It's time to start building the rafter system.

Installing the Mauerlat

The support for the frame of our future roof is the mauerlat - a wooden beam that is laid on the load-bearing walls of the house. The main function of the Mauerlat is to transfer and distribute the weight of the roof and the resulting loads (wind, snow, etc.) onto the supporting structures.

Mauerlat is the basis for almost any rafter system. An exception may be the roof of a house made of timber or the roof frame house- When building the frame with your own hands, in these houses you will use the upper wall beam instead of the mauerlat.

Most often (with the exception of the option that will be described below), 100x150 or 150x150 mm timber is used as a Mauerlat. It is optimal if the Mauerlat is laid “flush” with the inner surface of the building wall, and a brick barrier is erected outside at the level of the Mauerlat.

To lay the mauerlat along the perimeter of the building, we lay a monolithic concrete blind area. After the concrete has completely dried, we lay several layers of roofing material on it - it will provide a sufficient level of waterproofing and will effectively prevent the wood from absorbing moisture from the concrete base.

Most often, the Mauerlat is laid using the following technology:

• We install studs made of metal rods with a diameter of 10 mm or more into the concrete base. Studs can be installed as during construction concrete blind area, and later - by drilling holes in the concrete and securing pins in the holes cement mortar. The first method is preferable because it is less labor-intensive.
• Mauerlat from solid timber We lay 150x150mm along the blind area, and make marks in places where the timber touches the studs. Using the marks, we drill holes with a drill whose diameter corresponds to the diameter of the studs. We put the Mauerlat on the studs, and the studs should protrude from the timber by at least 10-15 mm.
• We fix the mauerlat on the studs using nuts, placing a wide flat washer between the beam and the nut to avoid damage to the wood when the nut is tightly tightened

Note! If you have it on hand welding machine and you have the skills to work with it, you can save money on stiletto heels. In this case, instead of studs, we use reinforcing bars, and simply weld the fixing nuts to them.

Another method of laying the Mauerlat makes the work somewhat easier.

Instead of timber, you can use two layers of 50x150 mm boards:

• We lay out the first row of boards along the perimeter of the walls and fasten them using anchor screws with a countersunk head and a metal sleeve. For drilling holes in concrete or brickwork We use a hammer drill, having previously drilled the board with a drill with a regular drill bit.
• We lay the second row of boards on top of the first row so that the joints of the boards do not coincide, and in the corners we lay the boards “in a bandage”
• We connect the rows together using 100 mm nails.

This fastening of the Mauerlat greatly facilitates lifting the material to a height - after all, the board is much lighter than timber.

And the strength of the resulting structure is quite sufficient, especially if a relatively light roof of a frame house is being erected.

Installation of rafters

The next stage in the construction of the roof frame is the installation of rafters. To make the work easier (especially if you work alone), all processing of the rafter beams is done on the ground.

This makes it more convenient to cut the beams to size, give them the desired shape using a template, cut out the necessary grooves and drill mounting holes. Only after this do we lift the rafter parts up and begin fastening them.

The technology for manufacturing a roof frame with a hanging rafter system is as follows:

• We make grooves in the mauerlat for installing rafter legs. The distance between the rafter legs is determined at the stage of choosing the type of rafter system, but in any case should not exceed 1.5 m - otherwise the structure will have clearly insufficient rigidity.

Note! If you plan to insulate the roof, then it is advisable to coordinate the distance between the rafters with the dimensions insulation material. By laying solid sheets or pairs of insulation sheets in the space between the rafters, you will significantly save time on trimming.

• We begin the installation of rafters with the gables - the end parts of the roof. Having installed the rafters at the ends, we stretch a cord between their ridges, and use it to guide us when aligning the intermediate rafters vertically.
• We insert the rafter legs into the grooves. To fix the rafter leg in the mauerlat, we use complex fasteners: the transverse displacement of the rafter is limited by a steel bracket, and the longitudinal displacement is limited by the bracket with which the rafter is attached to the mauerlat.
• When installing rafters, you need to remember that the rafters must protrude beyond the perimeter of the building. The optimal size of this protrusion (it is called an overhang or overhang of rafters) is 40 cm - this is how the walls of the building are protected from water flowing down the roof. In addition to the protrusion of the rafter beam itself, the overhang can be equipped by extending the rafters with an additional thinner board - the so-called “filly”. The “filly” is attached to the rafters using nails through a spacer - a short piece of board.

• We fix the lower parts of the rafters with strapping, which is used as a base for the attic floor. The strapping bars rest on the mauerlat.
• If it is necessary to extend the rafter beams (if their length is insufficient), we lay two beams on an overlay with an overlap of at least a meter. To fix the beams we use pins with a diameter of 8 to 12 mm.
• We connect the rafters to each other using pins, which we insert into pre-drilled holes. To prevent rotation of the rafters around the axis of the stud, each pair of rafters must be secured with two studs.
• If the roof width is within 6 m, then we connect the hanging rafters with an additional cross beam - a tie - in the shape of the letter “A”. We make the puffs from boards 50x100 or 50x150 mm, and fasten them to the rafters with self-tapping screws. It is also possible to install a tie made of 3 x 30x100 mm boards located on both sides of the rafters.
• In the upper part, we fix the trusses using a longitudinal ridge beam or ridge board.

• To enhance the upper rafter assembly You can connect the ridge beam to the tie with an additional piece of board. This is done to avoid deflection of the tie when there is a large distance between the rafters.

We repeat the above operations for all rafter pairs. After all the rafters are installed, you can begin arranging the sheathing.

Lathing

There are two types of roof sheathing: solid and thinned. The choice of sheathing type is determined by the type of roofing material.

To construct a continuous sheathing, OSB boards or moisture-resistant plywood of sufficient thickness (10 mm or more) are used, the sheets of which are stuffed onto the rafters through a counter-batten. Continuous sheathing is suitable for laying soft and rolled roofing materials.

When constructing thinned sheathing, beams or boards are placed on them, the distance between which depends on the dimensions of the roofing material used.

If austerity is necessary, for this type of lathing, you can use an unedged board instead of timber.

The thinned sheathing is placed on the rafters from top to bottom. To increase the strength of the structure, we fill the first rows of the sheathing, starting from the ridge beam, without a gap.

After the sheathing is completed, you can begin work on roof insulation, laying waterproofing and roofing work.

Despite the complexity of the process, it is quite possible to build a roof frame with your own hands. And if you take up the work “fully armed”, then you will invariably be successful.

Erection of the roof is important stage the entire construction of the house. That is why special attention is paid to the construction of the frame of the upper part of the building. To build a roof frame on our own, you need certain knowledge and experience. Next we will talk about how to make a roof frame.

Depending on the variety roofing structure The roof frame has several types:

• Rafter frame structure, the basis of which is wooden elements. It is used in private construction for the construction of pitched roofs.
• Metal carcass. It is made from profile metal beams and is used primarily in industrial construction.
• Concrete frame. Its design uses concrete slabs, which create a flat roof mainly in high-rise buildings.

Before you start construction frame structure building, it is necessary to decide on the choice of one of the given types and the frame of the rafter system, in which the load-bearing capacity is completely transferred to the trusses. To construct a rafter truss, a wooden beam is used, which in cross-section must be at least 15.0 × 5.0 cm in size. After attaching the rafters to the building and to each other, it is fixed to the frame roofing system battens.

The rafter structure is divided into layered and hanging. It is selected depending on the design features of the building. Both types of rafters are used in the construction of private houses and differ in that when hanging system the main beams rest on a mauerlat, which is arranged around the perimeter of the building and attached to the surface of the load-bearing walls on the top row of masonry. In practice, the Mauerlat is a wooden beam with a cross-section of 10.0×10.0 cm. The rafter legs on the upper side of the truss are fixed to each other using a ridge beam. The layered structure in the upper part is not attached to each other by the rafters. This wooden frame is made in a different way.

With a layered system, the trusses at the top of their structure rest on a longitudinal central wall or specially provided columns for supports.

When choosing the type of truss structure great importance have dimensions structures.

Note! Hanging rafters are used in the construction of roofs for houses, the distance between the external load-bearing walls of which does not exceed 6.0 m. If the span is greater than this value and there is a longitudinal central wall with load-bearing characteristics or supporting columns, then a layered rafter frame is used. In this case, it will not be subject to increased load from the weight of the roofing material.

You need to know that the Mauerlat is the main support for the frame structure and roofing material of the roof. The task of the Mauerlat is to take the loads from the entire roof structure and distribute them evenly onto the load-bearing walls of the building.

• Thanks to this structural element, the durability of not only the roof, but also the entire building as a whole increases. If this tier of timber had not been used, vertical loads from the roof would have acted with a destructive force on the load-bearing walls at individual points. In essence, the Mauerlat serves as the main support and protective function throughout the frame structure of the top of the structure. Such support is not needed only in the construction of wooden houses, in which the top of the walls ends with the laying of beams or logs. This important structural element must be installed when constructing the roof frame in such a way that the internal surfaces of it and the load-bearing walls are in the same plane. This will allow you to do interior decoration home more comfortable.
• On the street side, the mauerlat must be buried with brickwork so that the wood material is not exposed to natural phenomena. Walls made of blocks or bricks must be level at the top point concrete screed. It, in turn, must be covered with roofing felt in several layers. Instead of this material, heated bitumen can be used. Insulation material used to protect the Mauerlat from moisture that could be transferred to it from the walls. Excess moisture has a detrimental effect on wood material and reduces its durability.
• The most practical and reliable method of fixing the Mauerlat to the walls of a building is the use of metal pins that firmly fasten the surfaces of both elements. Holes are made in bricks or blocks required size. Ready-made metal studs, which are made from steel reinforcement, are inserted into the drilled holes. Then the beam for support is applied to the studs for fitting, marks are made and holes are also made along them in the Mauerlat.

Note! When installing, pay attention to the length of the studs. They should protrude from the body of the support beam at a distance of 1.5 cm. Threads should be cut at the ends of the metal parts, which are ultimately used for final fixation of the Mauerlat using large diameter washers and nuts. As an alternative to such fastening, welding can be used.

Installation of the rafter frame

The next stage of work is the installation of the roof truss frame. Before installing roof trusses, you need to purchase dry wooden elements so that they do not deform or warp over the subsequent time.

• During construction, the truss structure must include two rafter legs and tie rods to connect the former in their lower part. The ties are fixed to the rafter legs with anchor parts and bolts. Rafter trusses in the required quantity are attached to the Mauerlat and secured with simple technologies. They consist of making the required number of cuts in the support beam correct form. Into these grooves using simple manipulations rafters are installed. The distance between the truss structures depends on the exact dimensions of the roof, which are based on the dimensions of the house. In practice, the rafters should be located at a distance of up to 1 m from each other. It must be taken into account that in some roof frames rafters with a vertical direction are used. Such structural elements are used to construct high roofs with a vertical dimension of 3 m or more.
• The wooden lathing system perfectly connects the structural elements of the frame with each other. But before it is installed, it is necessary to ensure the stability of the roof trusses. For this purpose, a ridge-type beam is provided at the top of the structure. On the lower side, a temporary strapping is organized, which is removed after installing the planks or sheathing boards. As you can see, the sheathing plays important role not only for the installation of roofing material, but also for the reliable connection of all structural elements when making a roof frame with your own hands.
• The lathing system can be divided according to its type into intermediate and continuous. The choice of type of sheathing depends on what roofing material the roof will be covered with. Intermediate lathing is used if the roof is covered with dense sheet materials. In this case, there must be a certain distance between the slats.
• If the roof of the roof is expected to be soft or it is rolled into rolls, then continuous lathing is used. Only on such a surface can it be properly laid this type roofing material, and only in this way can long-term operation of the roof be ensured. Soft tiles will feel good on a solid sheathing. If this material is laid on an intermediate system, it will hang down and be used poorly.

For example, for galvanized sheets, metal tiles or slate, intermediate type lathing is well suited. But since these materials require fastening in certain places, the sheathing strips must be installed at a certain pitch. Therefore for proper construction the roof frame needs to be made preliminary calculations.

Note! Any materials made of wood are susceptible to fungus and insects, and they also burn. To protect wooden material from pests, beams and boards need to be protected antiseptic impregnations. In order for wood to lose its ability to burn, it must be treated with fire retardants. All wooden elements must be processed before starting installation work. This will increase the durability of the wooden roof frame.

In industrial construction, as well as in the construction of apartment buildings high-rise buildings Roof frames are not made from wooden elements. Rafter systems are made of profile metal. Lightweight metal the roof frame, which consists of steel of various profiles with thin walls, is reliable and for a long time operation. If we compare metal rafters and wooden ones, the former have a number of advantages.

• Metal elements, unlike wooden ones, are not subject to combustion. In the event of a roof fire metal constructions able for a long time withstand high temperature and do not allow the roof to collapse.
• When using metal rafters, there is no need to treat structural elements with antiseptics and fire retardants.
• Since the structure is not subject to infection by insects and fungi, and the surface of the elements is coated with zinc, which prevents corrosion, such a roof can be used for about 100 years.
• Metal rafters can be installed in any weather conditions.
• It should be noted that the rafters are easy to install. Installation requires a minimum of tools.
• Since the structure has a small mass, it does not exert large loads on the load-bearing walls of the structure.

Because metal rafters Large loads are not scary; any roofing material can be used as a roof covering.

Photo

Video

This video talks about installing a roof truss system.

There are many material options for building a private house on the modern market. The most common ones are brick, block and log. But in Lately Frame houses are becoming increasingly popular. They are characterized by simple and quick installation. You can do it yourself without resorting to the help of professionals. Below you will find recommendations on how to build the roof of a frame house with your own hands.

The roof structure is heavy and rests on the load-bearing walls of the house.. In case of frame house the roof is installed on vertical racks, lined with OSB boards up to the middle of the beam top harness. Decorative wall cladding is done after the roof is installed. And after this, the pediment and cornice overhangs are hemmed.

They are erected and sheathed before the roof is assembled. Therefore, before starting work, you need to prepare a project where the appearance of the roof and its slope will be determined. The pediment can be attached in parallel with the installation of the roof, but first you will still have to install the outer trusses, securely secured using braces.

The roof height of a frame house is usually more than 6 meters. Before starting work, you need to decide on the type of rafter system. Depending on the width of the span to be covered, the rafters may have a ridge board, a support screed or sloped braces if there is a central load-bearing wall. If the span is small, then rafter ties are usually installed. Attic walls can act as a supporting screed.

The rafters are secured using nails, self-tapping screws, metal plates or corners. The pitch of the rafters is determined within the range of 40 - 100 centimeters. This figure depends on the section size wooden beams, from which the racks are made. They can be within 2.5 - 5 meters.

The walls are laid on the external load-bearing vertical posts to support the rafter legs. wooden blocks with a cross section of 10x10 centimeters, called Mauerlats. A prerequisite for its installation is rigid fixation. It is best to connect the rafter legs using serrated overlays. If the overlapped span is more than five meters, it is necessary to install a special support under the rafters. After installation, the sheathing is installed to lay the roof covering. It can be made of OSB boards, plywood, edged, half-edged or unedged boards. This depends on the chosen roofing covering.

Subject to availability attic floor, the roof must be insulated. The insulation is placed between the rafters. Provided that its thickness is 10 - 15 cm, the cross-section of the rafters will be 15x5-15x7 cm. The cross-section of the rafters is selected according to the thickness of the insulation and the amount of snow load. To do this, calculations are made. If it is not possible to carry it out, then take a larger section of rafters. If the insulation thickness is more than 15 cm, rafters with a section of 20x7 cm are suitable.

When installing rafters on the mauerlat, a triangle equal to 1/3 of the rafter height is cut out in the support bar.

The roof may have one or more slopes. Wherein complex roof looks more interesting. But most the best option, both in terms of the amount spent and the work carried out, there will be a gable roof. It does not have valleys and has only one ridge, which will be a definite advantage when building a roof with your own hands, since these places in the structure are the most vulnerable.

When choosing the slope value, it is worth considering that with an indicator of less than 28 degrees, the load on the rafter system increases. This will lead to the need for strict calculation and control of load-bearing elements. And with a slope exceeding 50 degrees, wind loads increase. Optimal choice there will be a slope of 35-45 degrees. Such a roof will look better, and snow will not linger on it.

Roof installation

Let's look at roof installation using the example of a house with overall dimensions of 6x8 meters, a gable roof with a slope of 45 degrees, where bitumen slate is used as a roofing covering. The design includes an attic floor with a wall height of 1.1-1.6 meters.

The height of the walls of the attic floor should not be less than 1.1 meters. This will cause inconvenience during the operation of the under-roof space. In a cold attic, there is no need to raise the walls, and the roof structure will not change.

As a rafter system we will use two inclined rafter legs connected by a crossbar to ensure rigidity. It is also called a tie, jumper, cross member, etc.

The presence of an attic floor requires. Therefore, we will choose the parameters 15x5 cm as the cross-section of the rafters. And we will take the thickness of the insulation 15 cm (according to calculations for Moscow - 138 mm).

Next you need to decide on the length of the rafters. This can be done by making calculations. First of all, you need to decide on the angle of inclination. If you don't yet know which inclination to choose, follow the instructions below

Two slats 6 meters long need to be knocked together using nails in the shape of the letter “L”. This will clearly show what the roof truss will look like. The work is carried out on the ground. After this, it is worth preparing a test crossbar. It is a long strip that is applied to the rafters to measure its length.

After this, we lift the resulting truss onto the roof and rest it on the beam of the upper frame. Next, using the selection method, we determine the angle of inclination and, accordingly, the length of the rafters. When determining this parameter, it is necessary to take into account that the overhang of the rafters relative to the wall should be 30-55 cm.

The roof overhang is made to protect the walls of the house from precipitation. If there is no drain, the overhang should be at least 50 cm.

With this method of selecting the length of the rafters, it is necessary to take into account that the final height will be 5 cm lower due to installation on the mauerlat. To make such an installation, a rectangle of 5x5-5x6 cm is cut out of the Mauerlat bar for rafters with a section of 15x5 cm. And when trying on the rafters, it is necessary to mark where the support will take place and draw a vertical line. Thus, we will mark one side of the triangle, and mark the other on the ground at an angle of 90 degrees.

The pitch of the rafters is determined depending on the cross-section of the rafters and the roof slope. For the example under consideration, a step of 70-80 cm is best suited.

The next stage is preparation required quantity rafter legs. To do this, we use the already marked roof truss. This work should be carried out on the ground. Every next rafter leg We mark according to the first sample to prevent the accumulation of errors.

Then we proceed to fastening the crossbars. Best place for their placement - as low as possible. The crossbar is necessary to perceive the thrust, and the lower it is, the better it works.

In the presence of an attic floor, the best mounting height for crossbars is 2.25 - 2.35 meters. This will allow you to place doorways 2.1 meters high. When reducing the height of the openings, the crossbars can be placed lower. But at the same time, the height of the premises will be correspondingly lower. To make the height of the premises equal to 2.5 meters, which is considered the most convenient parameter, the crossbars are made at an identical height of 2.5 meters.

The presence of a counter-lattice will provide a gap for ventilation in the roof. There should be two of them - a lower and an upper ventilation gap, each 2-4 cm high. This is done regardless of whether the roof is insulated.

The lower ventilation gap is made under the waterproofing layer, and the upper one is made above. They allow condensation to evaporate and prevent water accumulation. The presence of both ventilation gaps will ensure that the wooden elements do not become covered with mold or mildew.

The counter-lattice is attached to the rafters lengthwise. The pitch for them is chosen in accordance with the pitch of the rafters. The cross-section of the boards for these purposes is 2x5 cm.

Next we attach the sheathing. The size of the section and pitch will depend on the selected roofing material. According to the conditions of our example, this is . Therefore, we choose unedged boards for the sheathing with a cross-section of 4x5 cm. And we will install them in increments of 35 cm.

We select the length of the sheathing taking into account the presence of an overhang beyond the outer rafter leg of 20-50 cm. It can be equated to the overhang of the rafters.

Material selection

Undried wood (sometimes called wet wood) is suitable for roofing work.. You can buy it at the sawmill. When choosing, pay attention to appearance. If the wood is gray, this may indicate the presence of fungus. Undried wood will require less financial investment than dried wood, since its price depends on the cubic meter rather than the square meter.

After purchasing, be sure to remove the bark from the wood - this will prevent the formation of bark beetles.

After calculating the roof elements, you should order the material. It must be taken into account that standard length lumber will cost less. And you can trim them yourself, using the leftovers for something else.