How to put on a roof. Calculator for calculating the lengthening of the rafter leg for the formation of an eaves overhang

It is better to entrust the installation of rafters to specialists, the roof is not the element of the building with which you can experiment. However, it is necessary to know the basics and features of how to put rafters on a house, if only in order to control the quality of work and be able to build a simple truss structure.

How to properly put the rafters on the house - let's deal with the terms!

If most people more or less imagine what a rafter is, then a problem may arise with the rest of the terms found in the case of a roofer. Mauerlat, crossbar, bed, stand, brace, run - it is unlikely to do without the help of specialized literature or an experienced builder! However, if you are reading this article, then you can do without them.

• Mauerlat is traditionally wooden beam with a section of 15 * 15 cm, which acts as an extreme lower support for the rafters, distributing the load from the joining points of the rafters to the entire upper wall area. IN Lately metal is often used instead of wood, for Mauerlats these are channels and I-beams. Mauerlat is installed with a slight indent from the outer edge of the wall and fixed. To prevent rotting and corrosion from below, the beams are insulated with roofing felt or other waterproof material. It is with this element that the installation of rafters often begins.
• Lezhen - additional beam to distribute the load from the rafters along the entire perimeter of the walls. They differ from Mauerlats in that the beds are installed inside complex roof structures, that is, they are not obligatory element roofs, but only as an addition in the right cases.
• Rack - vertical bar, which reinforces the truss structure from the inside. In turn, girders are installed on the racks, which are supported by struts - inclined beams that support horizontal elements and counteract compression or skew of the structure.
• Run - a horizontal beam that crosses the rafters perpendicularly along the entire length of the roof. Three types of purlins can be distinguished in the roof structure - ridge purlins (on which the rafters converge at the top of the roof), side purlins and Mauerlats, which are described above.
• Crossbar - a beam that is installed between the rafter legs, increasing the strength of the structure and its stability. Usually the cross section of the crossbars is 10 * 15 cm.
• Rafter legs or rafters - beams on which the roofing is directly installed. The rafter is also common name for the entire truss structure. For this element, a bar with a section of 10 * 15 cm is used. For the manufacture of a plank truss system, it is used pine board with a section of 50 * 150 mm or 60 * 200 mm.

Before installing the elements, it is necessary to accurately calculate their number, as well as take into account possible loads on the rafters: they can be one when installing slate, another for tiles and a third for.

For example, shed roof, built from a minimum number of elements, can easily withstand sheets of metal or slate, while under the tiles, over time, the rafters can deform, bend, which means that you will need to further strengthen the structure with racks or struts, and also use beams with a large section.

How to install the rafters - layered or hanging?

Rafter structures are divided into two groups - layered and hanging. Hanging rafters are usually built on the roofs of buildings without internal load-bearing walls. Hanging structure based on ridge run and Mauerlats, and at the bottom it is fastened with puffs, which prevent the rafters from moving apart under the influence of the load. It should be noted that much more timber is spent on hanging rafters, since this ensures their stability. You can save wood on plank rafters, since log options take 15-20% more timber.

Sloped rafters are installed on those buildings that have load-bearing walls inside, since this type requires a minimum of three support points. Layered elements can block the span maximum length up to 6.5 meters. If there is a need to increase the width of the covered area, then this can be easily achieved by installing additional supports: with one additional riser, the width can be increased to 12 meters, and with two - up to 15!

Depending on the section of the beams that are used for the manufacture of rafter legs, the spacing of the rafters varies from 0.8 to 1.2 m. The construction of the rafter frame, including runs, racks and struts, provides special stability to the rafter legs. This type is most often used in private construction, since on the one hand it turns out strong and reliable roof, and on the other hand, layered rafters are very economical- wood on them, in comparison with hanging ones, is needed many times less. Quite often, a roof is constructed by combining both types.

How to put rafters on the roof - what for?

To begin with, guided by detailed instructions, as given in a separate article, calculate how much material you need. Before installing the elements of the truss structure, they must be treated with compounds against fungi, insects and flame retardants that prevent ignition. Having spent money on these compounds before putting the rafters on the roof, you will extend their service life by decades.

How to put rafters on the roof - step by step diagram

Step 1: Installing Mauerlats

The most important connection in layered versions is considered to be the place of support. rafter leg on Mauerlat. It is with the fixing of the Mauerlat that the installation begins. To do this, metal pins are pre-concreted in the walls, which go deep into the walls by at least 40 cm. Wire twists with a diameter of at least 6 mm will also be suitable for the same purposes.

Step 2: Making the layout

Raise up two beams, which will be rafter legs. Cut notches on the left and right leg for emphasis on the Mauerlats, do not forget to mark for yourself which side of which beam belongs to. Install the bars, joining them at the top to make marks for the notches at the top. Notches are needed in order to make a connection with an emphasis, and not an overlap - this is considered extremely unreliable even with strong reinforcement with nails.

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 specifications

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. In case you are going to do truss 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 in the following way: 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 beam, which is attached around the entire perimeter of the outer 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 as a fastening product - it is better to fasten 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 attach the fasteners 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 words, 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, lay on top ridge beam (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 unnecessary part- according to this template, you can make blanks. 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.

Installation of rafters is the first and milestone roof construction. The overall success of the whole business depends on how the materials were selected, how the dimensions were maintained, whether processing and other work was carried out. Exist General requirements to materials, the installation procedure and other nuances that will help to correctly place the frame of the future roof.

A bit about terminology

Do-it-yourself rafter system requires certain knowledge. All structural elements have their own names, which we will now get acquainted with.

So, what is a rafter? This Basic structure roofs with one, two or more slopes. It includes:

• rafter legs - inclined beams or boards that create the shape of the roof;
• racks - vertical bars or boards supporting the end and rafter legs;
• struts - inclined beams supporting rafter legs.

Depending on the design, the rafters are inclined and hanging. The first type includes bars, which bottom rest against the wall of the house, the upper one - against the ridge of the roof, and in the middle they have an intermediate support. This design is placed if the rafter leg has a length of more than 5 m. Hanging rafters, respectively, do not have such supports.

Another component of the truss system is the run, which performs the function of strengthening the truss structures. This is a horizontally lying bar, perpendicular to the legs. There are ridge (in the place where the bars converge) and side.

In some designs, puffs are installed between the rafter legs. They create an additional connection and additionally strengthen the structure. In case several uprights, a horizontal beam is placed under them, which is called a bed. It takes on the load, evenly distributing it. All this is necessary to get the strengthening of the truss system. This will extend the life of the structure, as well as provide better protection from wind and other natural hazards.

The service life of the bars will increase special impregnations from fire, fungi and pests. Having dealt with the basic terms, we will consider the sequence of actions necessary to install the truss system.

Laying the groundwork

To perform the work, you will need a number of tools, among which must be the following:

• level;
• roulette;
• hand saw;
• axe;
• chisel or chisel;
• pliers or pincers.

Do-it-yourself installation of rafters is usually done with nails, the length of which is selected depending on the thickness of the beams and beams. They are enough to provide high-quality fastening all structural elements.

We will begin to consider the sequence of actions from laying the foundation for the truss system. in stone or brick houses Mauerlat is used for this, and in wooden structures- upper crown ( top harness). These are essentially runs encircling upper part walls. They are more massive than the beams that are used for the installation of the truss system.

Before laying the Mauerlat on a stone or brick wall you need to put a layer of insulating material. It will protect the wood from moisture that condenses on the surface of the stone. For these purposes, use the usual roofing material.

To ensure greater reliability of the roof structure, the rafter legs are cut into the Mauerlat or the upper crown. Such fastening of the beams will save the system from deformation, which may occur over time due to loads in the form strong wind or a thick layer of snow.

We put the rafters

How to install rafters? Depending on the angle of inclination of the roof slopes, they are divided into:

• pitched (angle of inclination more than 10 °);
• flat (angle of inclination less than 10°).

Depending on the size of the roof, the angle of inclination of the slope and the thickness of the bars in the system, a step is selected between the rafter legs. The minimum distance when attaching rafters to beams is 70 cm.

Experts note that the distance between farms also depends on the type roofing material, which the owner of the house intends to use in the construction of the house. For laying a soft roof is taken minimum distance. And for slate, metal tiles and others similar materials distance can be increased.

How to properly place the rafters so that the whole structure is even? To do this, first put one pair of legs on one end of the roof, and then the second on the other. A string is stretched between them, which acts as a guide. It will help to fix the rafters at the same level and evenly. It is important to ensure that the twine does not sag during work.

Fastening the rafters to the beams, as we noted above, is done with nails. Masters advise to make an end connection, and not an overlap. Between themselves, the components with which the installation of the truss system is carried out are also fastened with metal brackets. Self-tapping screws are used to fasten the rafters to the beams. This is considered a more reliable type of fastening.

It should be noted that part of the rafters extends beyond the edge of the wall for some distance. This creates a ledge that protects the wall from rain and snow. Standard scheme fastening the rafters to the beams provides for a minimum length of such a protrusion of 50 cm. The protruding part of the roof can be longer, depending on the needs of the owners of the future home.

The installation of pairs of rafter legs goes through the entire roof, from one edge to the other. The installation of the truss system must be carried out in such a way that it is possible to correct irregularities or structural errors in time.

Each pair of legs is attached in a supine position, after which it rises and is installed in the prepared grooves. After that, the rafters are fastened to the beams and pre-fixed. When several pairs are installed, they are fixed using runs.

The installation of rafters, as well as the creation of the entire roof, is a very responsible process. Taking into account that the base of the roof can be fixed to the wall using improvised means for lifting, subsequent work on its creation, which includes the installation of rafters, will be impossible without scaffolding, which also includes mobile structures. Scaffolding is used to lift materials to the desired height, in addition, they can be used as a working platform for a person and a place for laying building materials.

The device of the truss system.

Preparation of scaffolding and scaffolding

Do-it-yourself rafter installation can seem like a lot of work, but if you follow all the tips and follow them correctly, the process will be fun. If you are building a house, then you must use at least 3 scaffolds, in any case, their number should not be less than 2. For work, it is better to make mobile scaffolding, as they are very convenient. Installation of rafters should begin only after all safety issues have been resolved, in no case should this be neglected, since health is more important than construction speed.

Types of truss systems.

If there is no internal load-bearing wall in the house, that is, there is no additional support, and the construction legs rest only on the outer walls of the house, then hanging rafters should be used.

What is a rafter? Translated from the Old Russian language, this is a construction to support gable roof. And the rafter legs are inclined, with the help of which the roof slope is formed. The rafter legs are usually connected by "grandmothers" or "fillies", which are made vertically. The puff is a horizontal beam, with its help the rafter legs are connected.

Varieties of rafter designs

Roof structures, as a rule, contain the following components:

Schemes of layered rafters and their application.

1. Rafter legs are used to form the slope.
2. To transfer part of the load - columns or internal supports.
3. Various inclined elements (braces, braces) that perform the same functions as the racks.
4. Elements that fasten rafter legs to each other. Usually floor beams are used for this.

Triangle - optimal shape roof truss. This design has the highest rigidity.

Despite the many possible roof shapes, two types of rafters are commonly used:

1. Layered truss system;
2. Hanging rafters.

Figure 1. Installation of rafters.

The first case is used subject to the presence of internal load-bearing elements in the building structure. At the same time, the rafter legs have an emphasis not only on external walls, but also on internal columns or supports. Racks are used to transfer the load. Figure 1 shows the mounting schemes of the rafters.

The hanging structure has an emphasis only on the outer walls, and in the ridge the rafters rest on each other. Hanging rafters are used in the absence of intermediate supports, while the span width is less than 12 m. The design feature is high rate expansion load, to reduce it, special puffs are used. The legs of such a rafter system should be strengthened with struts, which will also reduce the pressure on the load-bearing walls.

Walls made of brick or stone require the installation of a Mauerlat. Mauerlat is a wooden beam, which usually has a section of 150x150 mm and is fixed with special studs. These studs must be pre-embedded into the wall. A waterproofing layer must be laid under the Mauerlat.

Do-it-yourself installation of hanging rafters on the Mauerlat: step by step instructions

For work you will need the following tools:

Scheme and installation hanging rafters.

• axe;
• hammer;
• knife for precise fitting of parts;
• pencil;
• plumb;
• roulette;
• building level.

To install the rafters, it is necessary to take a beam, the length of which will be 6 m, and the section 50x200 mm. It should be noted that if the cross section is suddenly small, then after some time, such a structure may sag. Based on the case described above, the roof slope, namely its angle, should be 33 º. The next step in installing the rafters is that, using scaffolding, you need to raise 2 beams and connect them at the top.

Knots of layered rafters.

1. On the rafter legs, you need to “cut the heel” in the following way so that the rafter rests well on the Mauerlat.
2. With the next rafter, you need to do the same. It will be nice if the rafter legs are marked as “left” and “right”.
3. After completing these works, the rafter legs must be connected.
4. After that, at the place where the rafter legs are connected, you need to perform with right angle"stump", so that the rafters at the top are not overlapped, and then fastened with nails. This method is unreliable, as the rafters rest against each other.
5. For correct execution"Hemp" should initially attach one rafter to another, then draw a line of their connection (you can use a pencil for this) and only then saw off.
6. To cook construction material on the ground, you need to measure and make several patterns at once.
7. Having done all the operations, we begin the installation of the rafters, first on one gable, and then on the other. Using nails, we fasten the rafters to the Mauerlat.
8. The following pairs of rafter legs are prepared according to ready-made patterns on the ground;
9. Then you need to pull the thread along the ridge between the already finished pairs of rafters and proceed with the installation of all the remaining rafters.
10. The distance at which the rafters are installed is 70 cm. Of course, in fact, it can be within 68-73 cm from each other. This is considered optimal distance for the roof, as it is reliable, and such a distance between the rafters will be convenient in the future when you stretch the film.
11. For these purposes, it is necessary to initially mark the Mauerlat, and then install the rafters on it.
12. It is worth noting that the adjustment must always be carried out with the help of a thread that is pulled between the rafters, when necessary, it will be possible to adjust the height of the rafter legs on the spot. In some cases, you need to put small boards under your feet.
13. Adjustment in the lower part in width, which is between the two rafters, is made according to the indicated markings on the Mauerlat. As for the upper part, here the adjustment is carried out using a temporary board with the same markings. This means that after each pair of rafters is installed, a board is temporarily nailed to the top of the left and right rafters according to the markings already made in advance, which corresponds to the markings applied to the Mauerlat.
14. In the described case, the hanging rafters will need to be connected with a horizontal bar, that is, with a puff, due to the large distance between the supporting walls. It is worth paying attention to the fact that initially the rafter pairs were connected horizontal board in the area of ​​\u200b\u200bthe ridge, thus forming a ridge knot.

Gable roof installation.

In the case under consideration, due to the large distance between the bearing walls, where the width of the house itself is about 11 m, the puff will not consist of one bar, but of several interconnected boards. Such a puff, made of several boards, will help solve several problems at once:

• the result is a tightening of the desired length:
• it is worth noting that the strength and reliability of tightening made of 3 boards with a total thickness of 60 mm is much higher than if it is one beam with a thickness of 60 mm.

Quality roof: summing up

For the required length, 4 and 6 m boards were cut, after which they were fastened with nails, twisted with nuts and studs with rafter legs.

Under constant control, you need to keep the distance that is between puffs. It should be the same as that between the rafter legs.

To do this, you need to use narrow boards, as in the case of adjusting the distance of the rafter pairs at the ridge, which are marked and correspond to the markings on the Mauerlat. Always keep your distance under control!

In addition to all this, the puff and the skate were connected by another 1st board. Given the fact that there is no retaining wall, the puff will simply bend, unable to support its own weight. In order to avoid such troubles, the tightening together with the ridge of the rafter pair are connected by a “headstock”. All of the above actions must be done with each rafter pair.

The rafter system is the supporting load-bearing frame for the roof. That is why it must be reliable, since the durability of the entire structure directly depends on the quality of the material from which the elements of the system are made, and the professionalism of its assembly.

it is quite possible to manufacture and install, having a master nearby who has already done this more than once. Without experience in this work and a reliable adviser, it is dangerous to take it yourself - it is better to entrust this event to a team of qualified craftsmen. However, if you nevertheless decide to try your hand, then you need to approach all the details of the system with all responsibility and caution, since the work is not only difficult, but also quite dangerous.

In order for the entire roof system of the house to last a long time, dried wood is selected for the manufacture of its elements. conifers. For rafters, a beam is needed, having a size of 100 ÷ 150 × 50 ÷ 60 mm.

Coniferous wood is light in weight, which is favorable for the entire construction of the house, since a heavy rafter system, creating a lot of pressure on the walls, can lead to damage and destruction.

Another advantage of coniferous material for the construction of the foundation for the roof is a high percentage of cm of leafiness in its structure, which means an increased ability to withstand atmospheric moisture.

For the manufacture of elements of the truss system, it must meet certain requirements that directly affect the durability of the entire structure:

• Wood for mounting the rafter system must be aged, which will eliminate the risk of its deformation in the structure.
• The moisture content of wood should be no more than 2-2.5%.
• If a hanging rafter system is arranged, then for the puffs and the rafters themselves, wood of only the first grade must be taken.
• When building a layered system, the second grade of material is also suitable.
• For retaining elements - racks and struts, you can also use the third grade of wood, however, while trying to choose raw materials, on which the minimum number of knots.
• The exact thickness of the blanks is selected depending on the weight of the selected roofing material and on weather conditions in this region. This is especially true for the maximum thickness of the snow cover in winter period. For example, for middle lane Russian regions, it is necessary to calculate the load on 1 sq..m . roofs in 180÷200 kg.
• In addition, the parameters of the rafter legs depend on overall dimensions truss system and its slope.
• Before installing the system, the wood must be subjected to anti-fungal and fire-fighting treatment.

When installing a structure, you need to know and types of loads that the entire roof system is exposed - they are also taken into account when choosing the parameters of the rafters and installing the structure.

• Live loads are the weight of a person at repair work roofs, snow cover in winter and the strength of gusts of wind.
is the weight of roofing, insulation and insulating materials.
• Seismic effects are special types of loads if the structure is located in seismically hazardous regions.

General design of the truss system

The most common the truss system has the shape of a triangle and is intended for arrangement. It includes several triangular elements, consisting of two rafter legs and auxiliary supports, and couplers. Each such triangular structure is called a rafter. The triangular elements of the system are located at a certain distance from each other, and most often it is from 50 to 80 cm.

This form has become traditional, as it creates better rigidity and reliability of the structure. It can end at the level of the walls or be continued for the installation of overhangs, which can be 40 centimeters or more long. Sometimes the rafters ending on the walls are built up with additional bars - “fillies”.

So, as mentioned above, the rafters are one triangular section, which includes:

• Two rafter legs connected on a ridge beam, or without its use, directly to one another.
• Braces or rafter legs are struts that support the rafter leg and lighten the load that falls on it. They rest against the bed and are fixed to it.
• Racks or vertical supports, consisting of bars. They, like the spacers, support the rafter leg, but closer to the center of the triangle. The rack is installed on the bed.
• A crossbar is a board that holds two rafter legs together.
• The fight is two crossbars fixed on both sides of the rafter leg. It performs the same task as the crossbar - it gives structural rigidity.
• Headstock is a vertical bar that is retaining and is installed in the middle of the triangle, resting against the floor beam and supporting the ridge. This part is used in hanging rafter systems.
• Run - they connect individual rafters in common system. They are parallel to the wall.
• Puffs are floor beams that connect the rafter legs, closing the rafter triangle.
• - a powerful bar installed at the upper end of the wall structure, to which elements of the truss system are subsequently attached.

There are three types of truss systems - these are layered, hanging and combined, i.e. including elements of both one and the other.

Hanging system

The hanging rafter system is used to cover buildings without internal main walls. The rafter legs are laid on the Mauerlat, fixed on load-bearing walls.

Since a large one falls on such a system, which is transferred to load-bearing walls, the following additional elements are used to relieve this stress:

• A puff that simultaneously performs the role of a floor beam. It can be used with a span of up to 6 meters. If the span is larger, then it is raised higher along the rafter leg, and in the lower part the triangle is also closed with a floor beam.
• Headstock supporting the ridge, it is mandatory to install if the span between the bearing walls is more than eight meters.
• Struts extending from the headstock at an angle and supporting the rafter legs.
• Support that strengthens the rafter leg.
• A ridge beam is required in this system.

All elements are attached to each other metal corners, staples or twisted with screws.

Layered system

The layered system is more stable and reliable, thanks to additional supports in the form of capital partitions inside the building. Their presence makes it possible to attic extra room.

When making such a decision, the racks in the truss system are installed closer to the load-bearing walls, freeing up space.

In this system, the rafter legs are installed on the Mauerlat, which is fixed to the side load-bearing walls. For the reliability of the installation, special grooves are cut in the rafter legs, and the elements are fastened together with brackets.

A ridge beam in this system is desirable if a large span is formed between the load-bearing walls, and it is planned to arrange a living space in the attic. The same applies to puffs, which in this case are fixed at the level of the ceiling of the future room.

You also need to know that the mauerlat must be very securely fixed to the wall with pins that extend 350 ÷ 400 mm deep into the wall, since it receives a large weight and dynamic load from the entire rafter system.

If it is assumed that the main walls of the building can shrink slightly, then the lower parts of the rafters are attached to the Mauerlat sliding fasteners, enabling the element to take the desired position without harming either the walls or the entire truss system.

Video: gable roof truss system

Installation of the truss structure

Having prepared suitable material and having a roof design project, you can proceed with its installation.

Gable roof

Mauerlat bars are fixed on the load-bearing walls on a pre-laid waterproofing material - ruberoid, and they mark the installation of rafters. It is very important to make the markings on both sides of the installation in the same way, otherwise the rafters will be skewed.

• The first rafters are adjusted and rigidly fastened directly at a height so as not to make mistakes in fastenings and in samples for installation on.
• Then, they are lowered down, and all the other rafters are made according to the first sample. On the ground, it is much easier and safer to fit all structural elements to each other and make reliable fastenings.
• When sawing the bars under the rafters, it is necessary to leave a small margin, i.e. make them a little longer than required so that you can fit them in place.
• To make it easier to navigate, exposing the first rafters, they take a beam, the length of which is equal to the distance between the outer edges of the walls - this will be the base or hypotenuse of the future triangle.
• The middle of the bar is determined, and a perpendicular board is temporarily nailed to it, having a height from the front wall of the structure to skate - peaks equilateral triangle.
• Then, laid out and fixed sides - legs triangles, they are rafter legs.

• If selected hanging system rafters, then the puffs are immediately marked and fixed.
• If it is planned to install additional fasteners, then they are fixed already in place, after installing the rafters on the roof.
• Further, the first rafters are first raised and temporarily installed. On each of them, places are marked where rectangular selections will be made to fix them on the Mauerlat.
• Then, the rafters are lowered down again, and grooves are cut out on them, having a right angle.

• For the first pair, taking it as a sample, the same grooves are measured and cut out on the remaining rafters.
• Further, two triangles rise to the walls, which are installed at the beginning and end of the future one. If a ridge beam is provided, then both installed parts are immediately connected to them.

Video: how the rafters are attached to the Mauerlat

• Cords are stretched along each slope between the already mounted rafters, which will also serve as guidelines for aligning the rest of the structure.
• First installed rafters are immediately reinforced by racks, struts and other elements of the system that give rigidity and reliability to the structure.
• Further, the remaining rafter pairs are raised and installed.
• If necessary, they are interconnected by runs and beds.
• When installing the rafter system, all its elements are temporarily fixed, since it is possible that some of them will have to be adjusted and reinstalled later. They are thoroughly fixed only after reconciliation of the entire system. Then corners, brackets, and, if necessary, sliding elements are used for fastenings. IN different places connections, self-tapping screws, nails, bolts, staples and studs are used.

If necessary, the rafters can be extended with "fillies"

• After the system is basically installed, the rafters can “filly” on overhangs - this is done so that the walls of the building are as well as possible covered from moisture getting on them during rain.
• The next stage of work is the device of the crate on top of the rafters. The thickness and width of the boards for this part of the structure are selected taking into account the installation technology of the selected roofing material - this will depend on the width, weight and length of its sheets.

Video: installation of a gable roof truss system

Single slope systems

It is generally accepted that a shed system is used only when constructing the roof of garages, sheds, gazebos and other non-residential buildings, but this is not at all the case. Such a roof also serves perfectly to cover residential buildings, and under it you can even arrange an additional warm room if you correctly calculate the slope of the structure.

A single-pitched system can be considered as half of a gable roof, but with some deviations. For example, if when installing a gable roof, the gable part is the width of the building, then with a single-pitched roof, its length.

The pediment can be raised from brick or wooden beams and boards. Its height will depend on the selected roof slope. The gable of the roof is raised high if an additional room is arranged under it.

The rafters in this system are easier to lay, but if the distance between the walls is large enough, then it is still necessary to install additional supporting elements for rigidity.

To correctly identify desired angle slope, you need to rely on the following factors:

• The thickness of the snow cover in winter and the average amount of precipitation in other seasons.
• Weight roofing, which is planned to cover the truss system.
• Temporary loads, in the form of gusts of wind.

The angle of this type of roof can vary from 5 to 45, and sometimes there are buildings with an angle of even 60 degrees.

Installation of a single-slope version is carried out on site, i.e. at a height, since the pediment and back wall buildings.

If the slope of the roof in a one-story mansion is not too large, then the rafters can be extended forward from the front or back of the house. This is done in order to arrange a veranda or terrace under the roof.

Attic systems

The most difficult to perform - attic systems roofs

If it is immediately laid down in the project to make the attic of the house residential, then you can choose one of two roof structures. The choice will depend on the desired attic area and ceiling height. It can be a gable with a high ridge or a broken mansard roof.

Gable roof

To arrange under a gable roof additional room, the space must be free from various additional fasteners. Therefore, you will have to get by with a minimum number of them.

Mandatory in this design will be racks and puffs - they will also perform the functions of the crate, on which it will be attached finishing material walls and ceiling of the building.

But in this case, it is very important to use massive bars for the floor beams, which will calmly withstand the weight of the truss system with insulation and roofing material, plus the entire load given by the pieces of furniture that will be installed in the room. In addition, it is necessary to mount the bars of the floor beams at a small distance from each other, which should not exceed 50 ÷ 60 cm, but in order for the walls of the building to withstand the entire load without problems, they must be quite massive and strong.

Installation of the system takes place in the same sequence as a gable roof.

Attic "broken" design

The mansard roof structure of the house is more complex than the usual gable, but its advantage is that living space, which is obtained as a result of its installation, will be much larger, and the ceiling will be higher.

An approximate diagram of the attic "broken" system

This type of roof is called broken, as the system consists of two parts, in each of which the rafters are located at a different angle.

The side rafters can be positioned at an angle of 30 or 45 degrees from the vertical - this is the most common installation options.

The top is fixed at an angle that can vary from 5 to 30 degrees from the horizon.

IN attic construction both rafter systems can be used. lower rafters it is preferable to arrange according to a layered system, but if there are no capital partitions in the building, then a hanging one can also be used. In the latter case, beams attic floor, as well as rafters, should be installed at a distance of no more than 50-60 cm from each other. It should be noted that the walls must be well fortified, since the load on them will be quite serious, much more significant than with a gable roof.

• The beginning of the construction of the lower truss system begins with the installation of racks, fixed with strapping from above, and from below - by floor beams. The distance between the rack systems will be the width of the room, and their height determines the height of the room.

Start of installation - installation of two rows of racks

• This frame will determine the placement of the remaining elements of the system.
• Next, you need to find the middle of the distance between the rows of racks, and this will determine location in the upper part of the attic. In this place, a vertical bar is installed, the same height as the rack system.

• Then, side rafters are installed, they are fixed to the rack strapping and a beam overlap, thus, triangles are obtained in which the rack and beam overlaps form a right angle.
• When all the side elements are installed, proceed to the installation of floor beams, they are also attached to the strapping bar and the end side rafter. A diagram of this bundle is shown in the first figure in this section.
• Further, the floor beams are connected to each other by a horizontal rail, which is stuffed on top of them, in the middle of the structure.
• Ridge rafters are installed, which are supported by struts. They are attached to the rail connecting the floor beams.

• On the ridge, the rafter legs can be fixed to the ridge board or connected by a metal or wooden plate to each other
• Sometimes, for structural rigidity, a supporting headstock is installed between the ridge and the floor beam.

• The crate of the gable walls is made with openings for windows. If the entrance is from the street, then on one of the gables, in addition, an opening for the door is provided.

• Further, if necessary, the entire truss system is sheathed with sheathing or plywood, if roofing material is chosen. soft roof, for example, flexible tiles.

Video: an example of installing a truss attic system

To equip the truss system is not at all simply, and you cannot cope with this work alone - you will need at least two assistants. It is desirable that at least one of the invited masters has some experience in this field of construction.