The layout of the rafters of a gable roof. Step-by-step installation of a gable roof - a guide to the home master

When designing any residential building, architects pay special attention to the roof, as it performs not one, but several functions at once, depending on its design features. It must be said that not all future homeowners are satisfied with the usual gable roof, although it can be called the most reliable, since it has only two pitched planes and one joint between them. Many are attracted more complex structures, which add a special attraction and originality to the structure. Other, more practical homeowners prefer attic structures that can simultaneously serve as a roof and a second floor.

The basis of any roof is an individual truss system, which has its own design features. Making the choice of the desired roof frame will be much easier if you figure out in advance which ones types and schemes of truss systems used in building practice. After receiving such information, it will become more clear how complex such structures are in installation. This is especially important to know if the roof frame is supposed to be built independently.

The main functional tasks of truss systems

When arranging pitched structures roofs, the truss system is a frame for covering and for holding materials of the "roofing pie". With proper installation of the frame structure will be created the necessary conditions for correct and non-insulated types of roofs that protect the walls and interior of the house from various atmospheric influences.

The roof structure is also always the final architectural element exterior design of the building, supporting its stylistic direction with its appearance. Nevertheless, the design features of the truss systems must first of all meet the requirements of strength and reliability that the roof must meet, and only then - aesthetic criteria.

The frame of the truss system forms the configuration and angle of inclination of the roof. These parameters largely depend on the natural factors characteristic of a particular region, as well as on the desire and capabilities of the homeowner:

The amount of precipitation in different periods of the year.
direction and average speed wind in the area where the building will be erected.
Plans for the use of space under the roof - arranging residential or non-residential premises in it, or using it only as air gap for thermal insulation of the rooms below.
Variety of planned material roofing.
Financial capacity of the homeowner.

Atmospheric precipitation and the strength of wind currents give a very sensitive load on the structure of the roof. For example, in regions with heavy snowfalls, you should not choose a truss system with a small angle of inclination of the slopes, as snow masses will linger on their surface, which can lead to deformation of the frame or roofing or leaks.

If the area where the construction will be carried out is famous for its winds, then it is better to choose a structure with a slight slope of the slope so that the sharp gusts that occur do not rip off individual elements of the roof and roof.

The main elements of the roof structure

Details and nodes of truss systems

Depending on the chosen type of truss system, the structural elements used can vary significantly, however, there are details that are present in both simple and complex roof systems.

The main elements of the pitched roof truss system include:

Rafter legs forming roof slopes.
- a wooden bar fixed on the walls of the house and serving to fix the lower part on it rafter legs.

The ridge is the junction of the frames of two slopes. It is usually the highest horizontal roof line and serves as a support on which the rafters are fixed. The ridge can be formed by rafters fastened together at a certain angle or fixed on a ridge board (run).
Sheathing - these are slats or beams mounted on rafters with a certain step and serving as the basis for the flooring of the selected roofing material.
Retaining elements, where you can take beds, girders, racks, struts, ties and other parts, serve to increase the rigidity of the rafter legs, support the ridge, bind individual parts into the overall design.

In addition to the structural details mentioned above, other elements can be included in it, the functions of which are aimed at strengthening the system and optimal distribution of roof loads on the walls of the building.

The truss system is divided into several categories depending on different features of its design.

attic space

Before proceeding to consider different types roofs, it is worth figuring out what an attic space can be, as many owners successfully use it as utility and full-fledged living quarters.

design pitched roofs can be divided into non-attic and attic. The first option is called just that because the space under the roof has a small height and is used only as an air layer that insulates the building from above. Such systems usually include or have several slopes, but located at a very slight angle.

The attic structure, which has a sufficiently large ridge height, can be used in different ways, be insulated and not insulated. These options include attic or gable option. If a roof with a high ridge is chosen, then it is imperative to take into account wind loads in the region where the house is built.

Slope slope

To determine the optimal slope of the roof slopes of the future residential building, first of all, you need to look at the already built low-rise neighboring houses. If they have been standing for more than one year and steadfastly withstand wind loads, then their design can be safely taken as a basis. In the same case, when the owners set a goal to create an exclusive original project, unlike standing side by side buildings, it is necessary to familiarize yourself with the design and operational features of various truss systems and make the appropriate calculations.

It should be borne in mind that the change in the tangent and normal values of the wind force depends on how large the slope of the roof slopes is - the steeper the angle of inclination, the greater the importance of the normal forces and the smaller the tangents. If the roof is sloping, then the structure is more affected by the tangential wind load, since the lifting force increases on the leeward side and decreases on the windward side.

Winter snow load should also be taken into account when designing the roof. Usually this factor is considered in combination with the wind load, since the snow load on the windward side will be much lower than on the leeward slope. In addition, there are places on the slopes where snow will definitely collect, giving a big load on this area, so it should be strengthened with additional rafters.

Roof slopes can vary from 10 to 60 degrees and must be selected not only with regard to the consolidated external load, but also depending on the roofing that is planned to be used. This factor is taken into account because roofing materials differ in their mass, their fixing requires a different number of elements of the truss system, which means that the load on the walls of the house will also vary, and how large it will be, also depends on the angle of the roof slope. Equally important are the features of each coating in terms of resistance to moisture penetration - in any case, many roofing materials need one or another slope to ensure the free flow of storm water or melting snow. In addition, when choosing a roof slope, you need to think in advance how the cleaning process will be carried out and repair work on the roof.

When planning this or that angle of the roof slopes, you need to know that the fewer joints between the sheets of the coating, and the tighter they are, the less you can make the slope of the slope, of course, if it is not supposed to arrange a residential or utility room in the attic space.

If a material consisting of small elements, for example, ceramic tiles, is used to cover the roof, then the slope of the slopes must be made steep enough so that water never lingers on the surface.

Given the weight of the roofing material, you need to know - the heavier the coating, the greater the angle of the slopes should be, since in this case the load will be correctly distributed to the rafter system and load-bearing walls.

Can be used to cover the roof the following materials: or profile sheet, galvanized steel, corrugated asbestos-concrete and bitumen-fiber sheets, cement and ceramic tiles, roofing felt, soft roofing and other roofing materials. The illustration below shows the allowable slope angles for various types of roofing.

Basic structures of truss systems

First of all, it is worth considering the basic types of truss systems regarding the location of the walls of the house, which are used in all roof structures. The basic options are divided into layered, hanging, and also combined, that is, including elements of both the first and second types of systems in their design.

fasteners for rafters

Layered system

In buildings where internal load-bearing walls are provided, a layered truss system is often installed. It is much easier to install than a hanging one, since the internal load-bearing walls provide reliable support for its elements, and in addition, fewer materials will be required for this design.

For rafters in this system, the defining reference point is the ridge board, on which they are fixed. The non-thrust type of the layered system can be equipped in three versions:

In the first version, the upper side of the rafters is fixed on a ridge support, called a sliding one, and their lower side is fixed by cutting to the Mauerlat. Additionally, the rafters in the lower part are fixed to the wall with wire or staples.

In the second case, the rafters in the upper part are cut at a certain angle and interconnected using special metal plates.

The lower edge of the rafter legs is attached to the Mauerlat with movable fasteners.

In the third version, the rafters are rigidly fastened in the upper part with bars or processed boards located horizontally, parallel to each other on both sides of the rafters connected at an angle, and a ridge run is pinched between them.

In the lower part, sliding fasteners are used to fix the rafters, just as in the previous case.

It is necessary to explain why sliding fasteners are often used to fix the rafters on the Mauerlat. The fact is that they are able to save the load-bearing walls from excessive stress, since the rafters are not rigidly fixed, and when the structure shrinks, they have the ability to move without deforming general design roofing system.

This type of fastening is used only in layered systems, which also distinguishes them from the hanging version.

However, in some cases, a spacer system is used for layered rafters, in which the lower end of the rafters is rigidly fixed to the Mauerlat, and in order to remove the load from the walls, puffs and struts are built into the structure. This option is called complex, as it includes elements of a layered and hanging system.

In building your dream home, are you already at the finish line, and it's time to deal with the intricacies of the truss system? Let's put it this way: pleasant worries await you: calculating the angle, weight and safety margin of the rafters, an agreement with a familiar craftsman or company, or preparing all the necessary tools for independent carpentry work.

And so that tomorrow all these worries do not become a headache and you do not worry about whether this or that knot is done correctly, we have prepared this article for you. So, let's figure out how to make high-quality rafters for gable roof with their own hands so that it is no worse than purchased ones.

Short production time.
Technological precision of all details.
The same, already fitted dimensions of all structural elements.

But then be prepared for such cons:

High cost (at least twice as high as if you planed the rafters yourself).
Delay in delivery (especially in season).
The use of low-quality or under-dried wood (and then the roof will “lead”).

So convenience or quality? If this is not the first time for you to cut or plan something out of wood, feel free to take on the manufacture of rafters! Here's what it all looks like in real life:

Rafters in the building world in a simple language are usually divided and the main ones, i.e. carriers, on which the roof rests, and on auxiliary ones, which are located inside the roof and serve as a support for hemming the ceiling and walls of the attic (if one is planned). The strength and reliability of the future roof depends on how accurately and correctly you calculate the truss system in advance.

The truss system of any gable roof itself consists of the following basic elements that you need to make:

Mauerlat.
Vertical racks.
Crossbars.
Rafter legs.
Struts.
Skate ride.

Complex roof structures with multiple elements are best left to a professional, but you can handle a small roof of a private house. To do this, you will need these simple formulas that will help you find out how thick the rafters should be, with what slope and what span:

How to draft a future roof?

The golden rule applies in the construction of roofs - measure seven times, and cut off only once. And first of all, it is important for you to understand that each rafter leg has its own individual location. Therefore, first make sure detailed project, and better in a special program. Only after that, according to your 3D model of the future roof, mark exactly where and what exactly the connections of the rafters with the Mauerlat and among themselves will be.

It is important to determine the angle of inclination of the rafters as accurately as possible and at what angle they need to make cuts. And don’t worry about how to make all these rafters for a gable roof yourself: you just need a regular machine.

Determine the angle of the roof: calculate the load

The angle of inclination of a gable roof is made from 5 ° to 90 °. But the most proven and standard option is 35 ° -40 °, where loads are most rationally distributed and building materials are consumed.

Straight slopes are built when only a non-residential attic will be under the roof in the future, the main function of which is ventilation and heat exchange regulation. But when the under-roof space is planned to be residential, attic, they initially plan the so-called broken gable roof. Its difference is that the slopes in the middle have, as it were, a kink that changes their angle to a steeper one. And for arranging the attic, and for protecting the whole house from the weather, this design is quite suitable.

Please note that most roofing materials are suitable only for slopes greater than 45°.

Fixed and variable roof loads

From the same loads depends on what step the rafters need to do for your gable roof. This table will help you choose the desired section of the rafter legs:

Indicators of rafters for deflection

Even strong-looking rafters may not be suitable for building the roof of a residential building due to the fact that they do not have enough deflection indicators. There are separate items in the section of SNiPs, which are called "Loads and Impacts".

And the easiest way to increase the strength of the rafters for deflection is to make the section larger. A little more difficult - to strengthen it with a beam, bringing its edge to the strut.

Reinforcing elements for rafters

The more racks, struts and fights - the more stability and stability the entire truss system has.

If you have suspicions or even an accurate count that simple design the roof will not withstand future loads, make additional reinforcement elements for it. Such prevention will never hurt, but it will save you from many problems. Note that it is especially disappointing when the roof of the garage falls through - right on the car. And for a residential building, such problems are not a joy.

Enhance rigidity roof structure struts, additional runs and support posts. Struts are designed to reduce the span of the rafter legs. The angle of their inclination to the horizontal is usually at least 45°.

A run is a horizontal beam, which is parallel to the ridge and is fixed on vertical posts. More on video:

Determine the type of roof: cold or warm?

And now about the concept of the attic. If you are building the roof of a bathhouse or a small master's room, it can be done using the most simplified technology - they put rafters, connected them in a ridge and covered them with sheets of roofing material. But for the roof of a residential building, where ventilation is important, this principle is indispensable. There will already be at least three levels:

The upper or first level of the rafters is about 200 mm.
The average is always equal to the height of the auxiliary rafters.
The third is already on the edge of the wall.

It is so convenient to lay insulation, because the roof of a residential building is distinguished by the fact that heat rises up and, in the absence of thermal insulation, the roofing is constantly heated.

Bottom line: in winter, the snow melts and slides down, freezing and accumulating even more near the cold eaves. There are many problems from this: long dangerous icicles, and a clogged drainage system, and the gradual destruction of the entire roof. Decide for yourself!

We determine the type of truss system: layered or hanging?

So, now is the time to think over the supporting bases for future rafters, which also need to be prepared in advance and on which many parameters of the roof itself will depend. So, the rafters are divided into layered, hanging and hybrid.

Hanging rafters are usually the lot of small and light roofs, the distance between the supports of which does not exceed 6 meters. But in buildings with a load-bearing middle wall or additional supports for the roof fortress, layered rafters are arranged. Or like this combined option:

Another difference is that the hanging truss system makes the Mauerlat work in compression, and the layered one in shear. But the main task of both layered and hanging rafters is to transfer the loads of the entire roof to the walls and foundation as evenly as possible.

We select material for rafters

So, if you have decided on future loads, it's time to choose the right material. As it is usually used for the manufacture of rafters:

Wood. Solid wood, boards or glued beams.
Lightweight metal profile. These are galvanized steel profiles.
Black metal. These are I-beams and steel channels.
Heavy reinforced concrete structures for industrial construction.

Dry board: an economical option

If heavy loads are not expected on the rafter system, then make the rafters from a dry planed board with a small section. But if knee-deep snow is not uncommon in your area and the roofing material will not be easy - then some of constituent elements you will have to make glued. That's the whole difference.

It is most convenient to make elongated side rafters and diagonal rafter legs from the board. So, a board 40 mm thick, which is often used for outbuildings, is not suitable for a roof. Not less than 50 mm! Moreover, the longer the rafter leg is planned, the wider the board itself should be. So, rafters 6 meters long will have to be made from a board 150 mm wide, and even longer - from a board 180 mm.

For the roof of a frame house, this is really one of the best options!

And also the rafters from the board are the most economical, and at the same time they are almost not inferior in strength to the timber ones. It is only important to choose the right section and use quality material. Therefore, when buying material, be sure to take a special device for measuring wood moisture and use it. There is nothing worse than damp rafters. And it's not just about future mold: such a roof will lead and warp, because this material changes its shape when it dries. At the rafters, fasteners will fly and even the cover of your gable roof will bounce in places. In short, no problems!

But from regular board it is most convenient to splice the rafters along the length:

Durable metal: resistance to dampness

And, you will be interested to know that rafters can be made not only from wood! So, iron truss systems, which were once used exclusively for industrial construction, are returning to their former popularity today. And, note, this material for the roof has many advantages, the most valuable of which is the complete absence of fungus from dampness. The under-roof space, after all, most often “pleases” with accidental leaks.

And the work itself with such rafters during installation is no more difficult than with wooden ones - see for yourself:

Beams: the benefits of quality wood

The beam is more durable, but it is bad because it has a lot of weight and cuts have to be made at the attachment points. For a log, this is not only a problem, but also some loss in the bearing capacity of such a rafter leg. But so far this material is the most popular for the manufacture of rafters.

Most of all, lumber is suitable for the manufacture of rafters, which meets the requirements of GOST 8486-86 or 2695-83. And this:

Humidity is not more than 18%, measured with a moisture meter.
Cracks that are not through and do not exceed half the length of the board.
For each linear meter - no more than three knots, and each of them - no more than 30 mm in diameter.

Therefore, when buying wood for rafters, be sure to check the documents from the seller that speak of product quality.

The type of wood is also important. The fewer knots and cracks on the beams, the better. Some varieties also please with good moisture resistance and resistance to decay and pests. For the roof, this is what you need. Therefore, we recommend making rafters from coniferous wood, which is rich in resin, and resin is a natural barrier against decay. But special processing is still needed.

And take into account also this fact: in the manufacture of the rafter system, the material needs to be purchased 5-7% more than necessary, because it will not always be possible to make an ideal cut of the rafter or cut of the required depth. There will still be an overrun, and therefore stock up on it in advance so that you have a tree of the same moisture content and properties for the entire rafter system.

Otherwise, if any individual elements roofs you had to purchase separately, they may take longer to dry (wood always dries), or vice versa. Distortions can turn out to be considerable, i.e. the entire roof frame will be constantly affected by different physical forces stretching and pressure. Any experienced roofer will tell you how bad it is and what it is fraught with. And therefore - take more material for the manufacture of rafters than you plan. If everything goes smoothly, there will be plenty to make the first bench in front of the new house.

Treatment with antiseptics and propylene

And at this stage it is already important to protect the future truss system from biological destruction. You do not want the roof to collapse after a couple of years of operation, do you? Therefore, be sure to treat the wood for the rafters with fire and bioprotection.

The rafters are usually impregnated with an antiseptic, and treated with a flame retardant on top. It is also possible to alternate such processing several times. If you use universal impregnation, be aware that it usually includes products with different service lives. For example, fire protection will end earlier than bio.

But the choice of means for processing today is huge. This and universal protective equipment, and a variety of flame retardants, and antiseptics. It's easy to decide: if you are building in a fairly hot and dry area, first of all use fire-retardant impregnations that deprive the wood of natural flammability. And if your house will stand where the humidity is high, almost all year round- protect from decay.

You can, of course, use both drugs - but only without mixing, otherwise the whole material will deteriorate. You just need to choose one agent as an impregnation, and the second as a protective surface layer. Just try to dilute everything in the concentration indicated by the manufacturer. But do not treat frozen or damp wood with anything: its fibers simply will not absorb anything.

Video hint on the topic of rafter processing:

Note that a brush or a spray when processing rafters give little result - complete immersion and subsequent drying are much better. Just use a regular container, cover it with a film from the inside and make a “bathroom” for future rafters. Moreover, it is desirable to turn all this on the ground, as soon as you bring the material to the place, because. in the finished rafter system it will be difficult to get to the internal elements of the joints. And they are the most defenseless in terms of moisture. Dry after processing the part so that all sides are ventilated, and for at least 24 hours.

Do not forget also that wood, like any natural material, is subject to biological destruction. Therefore, in addition to fire-bio-protection, it is important to consider waterproofing in all places where the truss system adjoins the brick walls of the house, if any.

We make the right cuts on the rafters

Now let's move on to practice. First of all, you definitely need to make a convenient template, according to which you will make even, identical rafters:

And follow these instructions:

You will have to tinker with a rigid mount:

If we are talking about moving nodes, then follow this principle:

In practice, everything is really simple:

As you can see, the eyes are afraid, but the hands are doing!

How to assemble a truss system?

Finally, the rafters are ready, and you can proceed with their installation.

Build on the ground or on the roof?

So, in fact, everything is quite simple and somewhat similar to a children's designer. The easiest and most convenient way is to make farms right on the ground, and only then raise them. It is a little more difficult to assemble the rafters directly on the roof, but it is easier to lift them there. So start from this: if you have the opportunity (a crane, for example) to drag 200 kg of one truss onto the roof, drag it, if not, lift each individual rafter by 50 kg using improvised means and do the assembly on the spot.

So, first of all, for convenience, make a template according to which you will assemble the trusses, and another template for mounting cuts on the rafters (use plywood). You just have to cut the mounting cuts on the rafters, attaching a template, and connect them together at a certain angle. This triangle is called the truss truss.

Attention to strength - rules for increasing the length

If the thickness or length of the board is not enough to make a normal rafter leg, build up the rafters. And there are several ways:

Bring the boards together, folding them with wide sides and stitching them with nails.
Lay the boards in half the length, resulting in a particularly strong rafter leg that can withstand considerable loads.
By making an oblique cut at the ends to create a vertical anti-slip stop, and connect with a bolt.
Lay two boards with an overlap of a meter in length, connecting the rafters with studs or nails.

Also consider when calculating that the roof ridge accounts for about 50% of the load from the entire truss system. Therefore, always make the beam for the ridge so that it has a safety margin of at least 25% more than it was originally calculated.

And the most vulnerable parts of the truss structures are the lower ones, those that rely on the Mauerlat.

Cooking truss trusses

fasten truss knots needed with:

External straight brace.
Metal corner plate.
Internal metal rod.

You can also connect such rafters with studs - it will even be stronger. To do this, instead of a cut, we now make a cut in half a tree and connect the rafters with a ledge. Next, we drill a hole for the stud 12-14 mm and fix it with nuts with wide washers.

Let's start with an overview of proven grandfather methods:

Here's how they work:

When assembling a hanging type truss truss, you need to connect the upper ends of the rafter legs. To do this, cut the end of each at exactly the same angle at which you make the roof, connect the beams with cut planes and fix with two nails. Close the joint with a wooden lining or a metal plate.

Another useful tutorial:

Lifting and installation of finished trusses

Already on the roof, first of all, you need to start by installing those rafters that form the two extreme gable roof trusses (they are also called gable). To further secure them, put temporary struts. Next, stretch a strong cord between the extreme tops of the trusses, which will become the level for the intermediate rafters.

Now we raise and place all the other roof trusses at a distance of at least 0.6 meters from each other. Again, if some of the structures turned out to be quite bulky, support them with the same temporary supports.

The rest is a matter of technique:

There are a lot of variations in the execution of the truss structure of a gable roof. Its appearance will largely depend on how the attic will be heated or cold, on the presence of load-bearing partitions, the choice of roofing material and, of course, on the taste preferences of the developer. Despite the variety of roof devices (rafter system and roofing pie), the basic installation rules remain unchanged.

The main stages of installation of a gable roof

Gable roof projects

Before starting the installation of the roof, it is necessary to draw the external forms of the future frame, indicating its configuration and height, so that in total the gable roof looks proportional to general structure, in a word, clearly imagine the arrangement of the rafters of a gable roof. This can be done in any way convenient for you, the main thing is to keep the scale for a real vision of perspectives. From experience it can be said that optimal height roofs are considered 1/3 of the value of the length of the house. We immediately embody our ideas regarding a straight or broken slope, branching in the main lines (Fig. 1), residential or non-residential attic space and the type of roof itself, it can be hanging and layered. The latter option is more often used in the construction gable roofs, since it is more practical and economical in terms of lumber consumption.

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

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

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

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

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

Consumables calculation example

V ideal when the installation of a gable roof is carried out according to the project, a selection of all structural elements is made with the designation of the length and quantity of each item. Using the rational cutting system, the volumes are summarized by:

Lumber (lm)
Insulation (m2)
Vapor barrier membrane (m2)
Roof covering (quantity in pieces, m2)

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

Width (a) - 5 m
Length (in) - 8 m
Corner at the top () - 1200
Slope angle (A, C) - 300

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

h \u003d ½ x a / tg  / 2 \u003d 0.5 x 5 / 1.73 \u003d 1.44 mm

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

per sine ½ angle at the apex

L (AB) \u003d 1/2 x a / sin  / 2 \u003d 1/2 x 5 / 0.87 + 0.5 \u003d 2.87 m

To the resulting length, do not forget to add the length of the cornice overhang, it is determined in the range of 0.5 ÷ 0.8 m. Therefore, the final size of the rafter leg will be 2.87 + 0.5 ÷ 0.8 = 3.37 ÷ 3.87 m (we will stop at the 3.5m option)

S over roofs \u003d a x L (AB) x 2 \u003d 5 x 3.5 x 2 \u003d 35 m2

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

Lumber for the crate is also easy to calculate. The step between the purlins (m) is 300 mm. Total

M \u003d L (AB) / m x in \u003d 3.5 / 0.3 x 8 x2 \u003d 187 p.m.

The board for the rafters is calculated in the same way. The step between the rafters is set, it can vary from 600 to 1000 mm, the cross-section of the board, the weight of the roofing cake are taken into account, the multiplicity, which is dictated by the width of the heat-insulating mats and the size of sheets of moisture-resistant plywood or OSB boards, plays an important role when making a continuous crate.

All other elements are calculated according to the above scheme.

Roofing tool kit

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

Roulette
Pencil or marker
Lace (beat)
Hammer
Roofing shears
Putty knife
roofing knife
Construction tape
Hacksaw
Screwdriver with a nozzle for self-tapping screws

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

Some devices greatly simplify the installation process, these are templates and rails with markings.

Roofing stuff

It is also worth paying attention to the so-called roofing details, which the developer often does not pay attention to, but they also affect the functionality and durability of the roofing system. The use of low-quality self-tapping screws (without the manufacturer's brand and with a thickness of EPDM gaskets less than 2 mm) leads to roof leaks. Not durable paintwork on fittings over time can be broken and spoil appearance roofs. Another element that is important when constructing a roof is snow retainers, their absence increases the risk of snow avalanches from the roof. In turn, this can lead to damage to the drainage system, buildings or cars under the roof. The next problem that worries developers is the problem of condensate, it is associated with insufficient ventilation of the under-roof space. To improve air exchange, it is necessary to provide for the installation of ventilation outlet elements in the roof surface, they allow you to ventilate the under-roof space more intensively, respectively, to avoid the problem of condensate.

They also forget to prescribe antiseptic formulations as an item in the expenditure item, without which it is impossible to imagine modern building from wood.

Rafter system of a gable roof. Installation and its features.

The beginning of installation begins with the installation of a support beam - Mauerlat. It is installed on load-bearing walls and fastened with pre-built anchor bolts or metal studs. The accuracy of the installation of the entire truss structure depends on how evenly the Mauerlat is mounted. His straightness

checked with a level, if necessary, alignment is done using linings or squeezing protruding parts. The flatness of the support beam allows one template to be used to make all the table legs on the ground, rather than having to fit each in place. It is recommended to perform the rafter support assembly on the Mauerlat using one of the methods indicated in Figure 3.

It is highly undesirable to wash down on a Mauerlat or on a ridge run, this can reduce bearing capacity supporting elements.

If the project provides for a ridge run, and this is more reliable option, the next step is to install the beam at the top of the gables. Mounting points A and B in Fig. 1 are made according to the schemes shown in Fig. 4

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

Roofing pie device

Upon completion of the installation of the truss system, they proceed to laying the vapor barrier layer. Roll material roll out parallel to the ridge run and fasten from the inside of the roof to the rafters. Butt joints are overlapped and sealed with adhesive tape.

From above, the space between the rafters is filled with insulation. To ensure the protection of thermal insulation from moisture due to possible leaks of the roof or condensate forming on the inner surface of the roofing, under-roof waterproofing is installed. She is nailed with outer side rafters with nails or staples and fasten with counter rail bars.

Next, a crate is installed, its design is selected depending on the roofing material. A ventilated gap is created with the help of the counter rail and the batten, which ensures the air-dry state of all roof materials.

Roofing is the final stage in the construction of the roof. It is applied according to the manufacturer's instructions. At the end of the main work, they begin to assemble and install drainage systems, ventilation, snow retainers and ladders for roof maintenance.

The rafter system is the basis of any roof. The complexity or accessibility of the roof structure depends on the type of roof chosen. Today we will talk about the most simple version- a rafter system for a gable roof. Experienced specialists tell about the structure of the roof frame, the features and functions of its elements, and how the truss system of a gable roof is made with their own hands.

Gable roof: types and benefits

Recall that a gable roof is a type of roof consisting of two planes (slopes) connected at an angle of a certain degree. It can be simple (symmetrical or asymmetric) and complex - broken.

The rationality of choosing a roof of two slopes is determined by its following advantages:

Profitability and simplicity of erection, in comparison with other roof structures.
Ease and availability of service at any time of the year.
Reliability and durability against wind, snowfall, hail and other natural influences.
The possibility of arranging the attic.
Better hydro and thermal insulation.

The necessary theoretical minimum for the construction of the truss system

The pitched roof structure is made of metal or wooden beams. Metal is a more "problematic" material. It makes the entire roofing system heavier, cools down and heats up quickly, is more difficult to install and requires the use of professional welding equipment. Based on this, in the construction of private houses (especially with their own hands), wood is mainly used.

There are two main options for the implementation of the truss system for a gable roof - a hanging type device (each rafter leg has two points of support) and a layered method (the rafters are connected at the bottom by a puff, forming a triangular truss, a carrier beam is installed in the middle). A layered structure is necessary if there is a distance of more than 10 meters between the bearing walls. Look at the image:

What does the system of truss elements consist of? Imagine a 3D projection. The skeleton of the roof consists of a mauerlat (rafter base), rafter legs, a ridge, racks, girders, lying, puffs, struts and battens. Mauerlat, lying and puffs are the lower parts of the system on which the entire future roof is being built. First, take a look at the illustration below, and then consider each element separately:

Mauerlat - the basis of all foundations

Mauerlat is a bar made of solid wood (mainly coniferous species) with a section of 10-15 cm. These are the optimal dimensions for the required strength and durability of the entire roof structure. The beam is laid on the load-bearing walls of the house to redistribute the spacer load on them.
There are two ways to install the bars of the truss base - with the transfer of load to the walls and without the transfer of gravity. The choice of mounting option for the Mauerlat should depend on the severity of the roofing system, the coating, the thickness of the load-bearing walls and the perimeter of the roof.

In the latter version, the Mauerlat is placed in a pocket, closer to the inner edge of the wall, and fastened to wooden corks with staples (each cork corresponds to the size of a brick and is part of the top row of brickwork).

The bars that take the load are mounted on the load-bearing walls from above with the help of anchors. Masters advise laying a rigid frame on a concrete base in the form of a belt in the wall. High-quality waterproofing is necessarily laid under the Mauerlat.

Details can be found in the video:

Lying - Basic Load Distributor

Lezhen performs functions similar to Mauerlat, and has the same dimensions. Beams are laid on internal load-bearing walls to evenly distribute loads from vertical struts and struts.

See the illustrations for the installation master class:

Rafter legs - ribs of the roofing skeleton

Rafters can be called the main component of the roof frame. This element cannot be left unused or replaced by another part. The legs of the rafters are wooden beams, the cross-sectional size of which can vary from 5 to 15 cm. The rafters rest on the Mauerlat and are interconnected by a ridge.

The installation process of the rafters can be seen in this video:

Skate - a small nuance with great meaning

The final element of the junction of two slopes is called the roof ridge. This is a rib located vertically at the highest point of the roof. A ridge run is mounted at the junction of the rafters. After that, the roof ridge is installed on it. This element fastens the rafters, performs a ventilation function and gives the roof aesthetics.

Racks - receivers of the main loads

Racks are powerful beams that take part of the load of the truss structure. They are installed vertically, usually in the center of the truss. If the project provides for an attic, then the racks are placed on both sides, closer to the roof slopes. When the attic is divided into two rooms, the racks are placed both in the center and on the sides.

Runs - rafter support

Ridge and side runs serve as a stiffener for roof trusses. The greater the load on the system (snowy winters, heavy roofing, big square roofs, etc.), the more purlins should be installed on the roof slopes.

Tightening - truss element connector

This structural detail performs the function of fixing the rafters at the base. Thus, a rafter triangle is formed - a farm. Puffs may not be installed in layered systems.

Struts - the strength of the structure

The struts serve as a support for the uprights and strengthen all structural elements. Experts recommend installing struts at an angle of 450. This increases the strength of the system and protects it from deformation under the influence of snow masses and wind.

Lathing - the basis for a roofing cake

Lathing - horizontal wooden slats with a section of 40-50 mm, located on the slopes perpendicular to the rafters. The main purpose of the crate is to fix the roofing material. The frequency and thickness of the battens depends on its type. In addition, the lathing helps to move materials during the roofing and serves additional element structural strength.

Overhang elements - final moments

The edge of a roofing system is called an overhang. This is a protrusion of the rafter system above the wall by about 40 cm. The overhang box consists of the following elements: filly (slats connecting with rafters), frontal and cornice boards. The purpose of the overhang is to protect the walls from getting wet during rains and melting snow.

A step-by-step guide to installing a gable roof truss system

To get started, we suggest that you familiarize yourself with the illustration that we have prepared for you:

And now consider the three main stages of the process of installing a simple gable roof truss system:

Stage 1: Calculations and drafting

Work should begin with the preparation of the roof project. It will contain all sizes, shapes and types of fasteners of structural elements. To create a quality project, you need to make the following calculations:

Calculation of constant and variable loads on the truss system. Permanent loads include the weight of the roof and finishing materials(the attic is also taken into account additionally). Variable loads are the force of wind, rain, snow, etc. The maximum can be considered the main load of up to 50 kg per square meter roofs, and variable - up to 300 kg (taking into account possible snow blockages).
Accounting for seismic activity, storm winds and features of the location of the house. For example, if the house is surrounded by other buildings, then the load on the roof is significantly reduced.
The choice of the angle of inclination of the gable roof. When calculating the angle of inclination, the following factors are taken into account: the higher the angle, the more materials will go to the roof (and money, respectively); the slope depends on the roofing material - the softer the roof, the smaller the angle of inclination (for example, for soft tiles an angle of 5-200 is selected, and if you use slate or ondulin, you must select a slope of 20-450).
Calculation of the pitch and length of the rafters. The step length between the trusses varies from 60 to 100 cm. The heavier the roofing, the more often the rafters need to be distributed. To calculate the length of the rafter, we use the Pythagorean theorem, taking the rafter leg as the hypotenuse of the triangle. The first side will be considered half the width of the house, and the second - the selected roof height. Then we add another 60-70 cm of margin to the hypotenuse we found.

When all calculations are made, you need to make a drawing of parts, connections and the entire project as a whole.

Stage 2: Acquisition and preparation of the necessary materials and tools

For work, it is necessary to purchase lumber, according to calculations, bolts, corners, anchors and other connecting parts, and prepare the appropriate tools (drills, levels, meters, jigsaw, etc.). Wood for load-bearing beams and rafters must be solid and of high quality - knots and wormholes are unacceptable.

Antiseptic, anticorrosive and fireproof wood treatment is a must at this stage. You can start working with the material one day after processing.

Stage 3: Installation of the roof truss structure

It is better to mount the roof frame in dry, not windy weather, so as not to encounter additional difficulties during operation. At this stage, we will dwell in more detail and consider step-by-step instructions for installing the truss system.

Installing the truss system: a step by step guide

Step 1. Laying the Mauerlat and the bed. There may not be a bed if there are no more load-bearing walls inside the house. Before laying the Mauerlat on the walls, it is necessary to lay out waterproofing material, for example, roofing material. We measure the tape of the desired width, cut it off and lay the waterproofing on the edge of the wall (where the frame will be installed).

We mark the beams of the desired section and length, trim and begin to form the base frame. Mauerlat should be located on the outer edge of the wall (if a hanging structure is planned) or in a special niche on the wall in front of the threshold (if the roof system is layered). The beds under the racks are laid on the internal load-bearing partitions. Mauerlat is attached to the wall and wooden corks staples, studs and anchors.

And we invite you to familiarize yourself with the illustration that we have prepared for you:

When laying the frame along the entire length of the wall, we may encounter the need to connect the base beam. They should be performed by cutting the bars at an angle of strictly 90 degrees. Fastening is carried out with high-quality bolts.

How not to damage bricks or blocks when lifting roof boards?

Choose the edge of the wall through which it is most convenient to feed the beams for the roof frame. This edge must be protected with a wooden square. Two trimmings of a rough board about a meter long will do, which need to be knocked together at a right angle. Put the square on the outer edge of the work wall. Now you can lift the boards without fear of damaging walls or window sills with them.

Step 2 Installation of rafters. The first step is to install the extreme rafters. In order for the rafters to be held evenly, we install the racks in the center. We attach the racks to the Mauerlat using an iron corner and self-tapping screws. This temporary part is removed after the installation of all rafters. We fasten the extreme rafters with crossbars and install a ridge run. Mounting type - metal corner, self-tapping screws and studs.

The illustration shows the process of mounting the rafter legs and attaching the rafters to the run:

But how to attach the rafters to the Mauerlat:

Between the extreme farms, it is imperative to stretch the construction thread along which we will level all the slope rafters.

Now we mount everything truss elements according to a predetermined pattern. We join the rafters over the ridge run.

For more information about the process of installing rafters, see this video:

A system of special racks will help strengthen the rafter legs. On the Mauerlat, wooden bars are fastened from boards of the same thickness as the rafters. The bars must be fixed in increments equal to the selected distance between the rafter legs according to the markup. The length of each board is approximately 40 cm. These racks will transfer the load to the power plate and load-bearing floors. The bars must be fixed to the base with steel corners. Now the rafter legs need to be installed so that one side of each is adjacent to the rack. Then, on the other side of each rafter, we fasten the same rack and grab all three parts with 12 mm studs.

After mounting all the legs of the rack, they are cut flush with the bevel of the rafters from the side of the street. From the inside, an empty corner is formed between the uprights, which must be closed with a wooden triangle (you can use trimmings from bevels).

All rafter legs should be additionally strengthened with crossbars, racks, struts and the joints should be reinforced with metal plates. The full process of strengthening the rafters can be viewed on the video:

Step 3. Waterproofing and crate. On the finished rafter ribs, you need to lay a high-quality waterproofing vapor-permeable material under the crate. The entry of the insulating sheet (sheet to sheet) is 15 cm. A counter crate is stuffed onto the waterproofing wooden slats along the edges of the rafters. From above, a crate of the same rails is installed perpendicular to the rafter legs.

When installing the frame, it is necessary to take into account the presence of a chimney and the obligatory ventilation of the ridge. The distance between the boards of the crate is on average 300 mm. This scheme is suitable for all types of solid roofs. When choosing a soft roofing material, the crate is made of solid sheets of moisture-resistant plywood.

The rafter system is ready. Now it's the turn of the installation of roofing material, internal insulation roof and attic arrangement (if provided by the project).

So it's time to answer main question our topic: is it worth doing it all with your own hands? Do not believe anyone who tells you that it is easy and simple. But if you have golden hands and a great desire to make quality roof"for yourself", then go ahead! We wish you good luck!

Rafters perform a number of significant roofing functions. They set the configuration of the future roof, perceive atmospheric loads, and hold the material. Among the rafter duties are the formation of even planes for laying the coating and providing space for the components of the roofing pie.

In order for such a valuable part of the roof to flawlessly cope with the listed tasks, information about the rules and principles of its construction is needed. The information is useful both for those who are building a gable roof truss system with their own hands, and for those who decide to resort to the services of a hired team of builders.

In device roof frame for pitched roofs, wooden and metal beams are used. starting material for the first option is a board, log, beam.

The second is constructed from rolled metal: channel, profile pipe, I-beam, corner. There are combined structures with steel most loaded parts and wood elements in less critical areas.

In addition to the "iron" strength, the metal has a lot of disadvantages. These include heat engineering qualities that do not satisfy the owners of residential buildings. Disappointing need for the use of welded joints. Most often, industrial buildings are equipped with steel rafters, less often private change houses assembled from metal modules.

In the case of self-construction of truss structures for private houses, wood is a priority. It is easy to work with it, it is lighter, “warmer”, more attractive in terms of environmental criteria. In addition, nodal connections do not require welding machine and welding skills.

Rafters - a fundamental element

The main "player" of the frame for the construction of the roof is the rafter, among the roofers called the rafter leg. Beds, braces, headstocks, girders, puffs, even Mauerlat may or may not be used depending on the architectural complexity and dimensions of the roof.

The rafters used in the construction of the gable roof frame are divided into:

Layered rafter legs, both heels of which have reliable structural supports under them. The lower edge of the layered rafter rests on the Mauerlat or on the ceiling crown of the log house. The support for the upper edge can be a mirror analogue of an adjacent rafter or a run, which is a beam horizontally laid under the ridge. In the first case, the truss system is called spacer, in the second, non-spacer.
hanging rafters, the top of which rests against each other, and the bottom is based on an additional beam - puff. The latter connects the two lower heels of adjacent rafter legs, resulting in a triangular module called a truss truss. The tightening dampens the tensile processes, so that only a vertically directed load acts on the walls. The design with hanging rafters, although it is spacer, does not transfer the spacer itself to the walls.

In accordance with the technological specifics of the rafter legs, the structures constructed from them are divided into layered and hanging. For structural stability, they are equipped with struts and additional racks.

For the arrangement of supports for the top of the layered rafters, beds and girders are mounted. In reality, the truss structure is much more complicated than the elementary patterns described.

Note that the formation of a gable roof frame can generally be carried out without a truss structure. In such situations, the alleged planes of the slopes are formed by slegs - beams laid directly on the bearing gables.

However, we are now specifically interested in the device of the truss system gable roof, and it can involve either hanging or layered rafters, or a combination of both types.

Subtleties of fastening rafter legs

The rafter system is fastened to brick, foam concrete, aerated concrete walls through the mauerlat, which in turn is fixed with anchors.

Between the Mauerlat, which is wooden frame, and walls made of these materials must be laid with a waterproofing layer of roofing material, waterproofing, etc.

The top of the brick walls is sometimes specially laid out so that something like a low parapet is obtained along the outer perimeter. So it is necessary that the Mauerlat placed inside the parapet and the walls do not burst the rafter legs.

The rafters of the roof frame of wooden houses rest on the upper crown or on ceiling beams. The connection in all cases is made by cutting and duplicated with nails, bolts, metal or wooden plates.

How to do without furious calculations?

It is highly desirable that the cross section and linear dimensions of the wooden beams be determined by the project. The designer will give clear calculation justifications for the geometric parameters of the board or beam, taking into account the entire range of loads and weather conditions. If there is no home design development master at his disposal, his path lies on the construction site of a house with a similar roof structure.

You can ignore the number of storeys of the building under construction. It is easier and more correct to find out the required dimensions from the foreman than to find them out from the owners of a shaky unauthorized construction. After all, the foreman is in the hands of documentation with a clear calculation of the loads per 1 m² of roof in a particular region.

The installation step of the rafters determines the type and weight of the roofing. The heavier it is, the smaller the distance between the rafter legs should be. For laying clay tiles, for example, the optimal distance between the rafters will be 0.6-0.7 m, and for a profiled sheet, 1.5-2.0 m is acceptable.

However, even if the step required for the correct installation of the roof is exceeded, there is a way out. This is a reinforcing counter-lattice device. True, it will increase both the weight of the roof and the construction budget. Therefore, it is better to deal with the step of the rafters before the construction of the rafter system.

Craftsmen calculate the pitch of the rafters according to design features buildings, tritely dividing the length of the slope into equal distances. For insulated roofs, the step between the rafters is selected based on the width of the thermal insulation boards.

On our website you can find, which may also help you a lot during construction.

Rafter structures of layered type

Rafter structures of the layered type are much simpler in execution than their hanging counterparts. A justified plus of the layered scheme is to provide full ventilation, which is directly related to the longevity of the service.

Distinctive design features:

Mandatory presence of support under the ridge heel of the rafter leg. The role of a support can be played by a run - a wooden beam resting on racks or on inner wall buildings, or the upper end of an adjacent rafter.
The use of Mauerlat for the construction of a truss structure on walls made of brick or artificial stone.
The use of additional runs and racks where the rafter legs, due to the large size of the roof, require additional support points.

The minus of the scheme is the presence of structural elements that affect the layout of the internal space of the operated attic.

If the attic is cold and the organization of useful premises is not supposed to be in it, then the layered construction of the truss system for the installation of a gable roof should be preferred.

A typical sequence of work on the construction of a layered truss structure:

First of all, we measure the height of the building, the diagonals and the horizontalness of the upper cut of the skeleton. When identifying vertical deviations of brick and concrete walls, we eliminate them with a cement-sand screed. Exceeding the heights of the log house we squeeze. By placing chips under the Mauerlat, vertical flaws can be dealt with if their magnitude is insignificant.
The floor surface for laying the bed must also be leveled. He, the Mauerlat and the run must be clearly horizontal, but the location of the listed elements in the same plane is not necessary.
We process everything wooden details structures before installation with flame retardants and antiseptics.
We lay waterproofing on concrete and brick walls for the installation of a Mauerlat.
We lay the Mauerlat beam on the walls, measure its diagonals. If necessary, we slightly move the bars and turn the corners, trying to achieve the perfect geometry. Align the frame horizontally if necessary.
We mount the Mauerlat frame. The splicing of the beams into a single frame is carried out by means of oblique cuts, the joints are duplicated with bolts.
We fix the position of the Mauerlat. Fasteners are made either with brackets to wooden plugs laid in the wall ahead of time, or with anchor bolts.
We mark the position of the bed. Its axis should recede from the Mauerlat bars at equal distances on each side. If the run will be based only on racks without lying down, the marking procedure is carried out only for these columns.
We install the bed on a two-layer waterproofing. We fasten it to the base with anchor bolts, connect it to the inner wall with wire twists or staples.
We mark the installation points of the rafter legs.
We cut out racks according to uniform sizes, because our bed is set to the horizon. The height of the racks must take into account the dimensions of the section of the run and the bed.
Installing racks. If provided by the project, we fix them with spacers.
We lay the run on the racks. We check the geometry again, then install the brackets, metal plates, wooden mounting plates.
We install a trial rafter board, mark the places of trimming on it. If the Mauerlat is set strictly to the horizon, there is no need to adjust the roof rafters in fact. The first board can be used as a template for making the rest.
We mark the installation points of the rafters. Folk craftsmen for marking usually prepare a pair of slats, the length of which is equal to the gap between the rafters.
According to the markup, we install the rafter legs and fasten them first at the bottom to the Mauerlat, then at the top to the run to each other. Every second rafter is screwed to the Mauerlat with a wire bundle. V wooden houses the rafters are screwed to the second crown from the top row.

If the rafter system is done flawlessly, the layered boards are mounted in random order.

If there is no confidence in the ideal structure, then the extreme pairs of rafters are installed first. A control twine or fishing line is stretched between them, according to which the position of the newly installed rafters is adjusted.

The installation of the truss structure is completed by installing the filly, if the length of the rafter legs does not allow the formation of an overhang of the required length. By the way, for wooden buildings the overhang should “go beyond” the contour of the building by 50 cm. If the organization of the visor is planned, separate mini-rafters are installed under it.

Another useful video about the construction of a gable truss base with your own hands:

Hanging truss systems

The hanging type of truss systems is a triangle. The two upper sides of the triangle are folded by a pair of rafters, and the puff connecting the lower heels serves as the base.

The use of tightening allows you to neutralize the effect of the thrust, therefore, only the weight of the crate, the roof, plus, depending on the season, the weight of precipitation, acts on walls with hanging truss structures.

The specifics of hanging truss systems

Characteristic features of hanging type truss structures:

Mandatory presence of a puff, made most often of wood, less often of metal.
The ability to refuse the use of Mauerlat. A frame made of timber will be successfully replaced by a board laid on a two-layer waterproofing.
Installation on the walls of ready-made closed triangles - roof trusses.

The advantages of the hanging scheme include the space under the roof free from racks, which allows you to organize an attic without pillars and partitions. There are disadvantages.

The first of these is the limitation on the steepness of the slopes: their slope angle can be at least 1/6 of the span of a triangular truss, steeper roofs are strongly recommended. The second disadvantage is the need for thorough calculations for the competent device of cornice nodes.

Among other things, the angle of the truss truss will have to be set with jewelry accuracy, because. the axes of the connected components of the hanging truss system must intersect at a point, the projection of which must fall on the central axis of the Mauerlat or the lining board replacing it.

Subtleties of long-span hanging systems

Puff - the longest element of the hanging rafter structure. Over time, it, as is typical of all lumber, deforms and sags under the influence of its own weight.

Owners of houses with spans of 3-5m are not too concerned about this circumstance, but owners of buildings with spans of 6 meters or more should think about installing additional parts that exclude geometric changes in tightening.

To prevent sagging in the installation scheme of the truss system for a large-span gable roof, there is a very significant component. This is a pendant called a grandmother.

Most often, it is a bar attached with wooden surfs to the top of the truss truss. You should not confuse the headstock with the racks, because. her Bottom part should not come into contact with the puff at all. And the installation of racks as supports in hanging systems is not used.

The bottom line is that the headstock, as it were, hangs on a ridge knot, and a puff is already attached to it with the help of bolts or nailed wooden plates. Threaded or collet type clamps are used to correct slack.

Adjustment of the tightening position can be arranged in the zone of the ridge knot, and the headstock can be rigidly connected to it with a notch. Instead of a bar on non-residential attics reinforcement can be used to make the described tightening element. It is also recommended to arrange a headstock or suspension where the puff is assembled from two bars to support the connection area.

In an improved hanging system of this type, the headstock is complemented by strut beams. The stress forces in the resulting rhombus are extinguished spontaneously due to the competent arrangement of the vector loads acting on the system.

As a result, the truss system pleases with stability with a slight and not too expensive upgrade.

Hanging type for attics

In order to increase usable space the tightening of the rafter triangles for the attic is moved closer to the ridge. A perfectly reasonable move has additional advantages: it allows you to use puffs as the basis for filing the ceiling.

It is attached to the rafters by cutting with a semi-frying pan with a duplication of a bolt. It is protected from sagging by installing a short headstock.

A noticeable drawback of the attic hanging structure is the need for accurate calculations. It is too difficult to calculate it on your own, it is better to use a ready-made project.

Which design is more cost effective?

Cost is an important argument for an independent builder. Naturally, the price of construction for both types of truss systems cannot be the same, because:

In the construction of a layered structure for the manufacture of rafter legs, a board or beam of small section is used. Because layered rafters have two reliable supports under them, the requirements for their power are lower than in the hanging version.
In the construction of a hanging structure, the rafters are made of thick timber. For the manufacture of puffs, a material similar in cross section is required. Even taking into account the rejection of the Mauerlat, the consumption will be significantly higher.

Saving on the grade of material will not work. For the bearing elements of both systems: rafters, purlins, beds, Mauerlat, attendants, racks, lumber of the 2nd grade is needed.

For crossbars and puffs working in tension, you will need the 1st grade. In the manufacture of less responsible wooden slips, the 3rd grade can be used. Without counting, we can say that in the construction of hanging systems, expensive material is used to a greater extent.

Hanging trusses are assembled in an open area next to the object, then transported assembled upstairs. To lift weighty triangular arches from a bar, you will need equipment, for which you will have to pay rent. And the project for complex nodes of the hanging version is also worth something.

Video instruction on the installation of a truss structure of a hanging category:

There are actually many more methods for constructing truss systems for roofs with two slopes.

We have described only the basic varieties that are actually applicable for small country houses and buildings without architectural ideas. However, the information provided is sufficient to cope with the construction of a simple truss structure.