Are you just about to build your house and are looking for an unusual and energy-saving project? This is different from conventional roof the fact that its two slopes have different lengths or angles of inclination.
More often gable roof with different slopes is implemented when it is necessary to create a single complex from a house and an extension, although recently they have begun to forget about the classical canons of roof construction and about ordinary architectural tasks. Do you want to know why? This is interesting!
American architect Frank Lloyd once said: "Great architecture is evidence of the greatness of mankind." Indeed, the evolution of the roof from ancient times to the present time is amazing. What architects of different times did not do with the roof of a residential building!
And what forms they did not create. Although the architecture of the last century is especially surprising with its diversity, where in the pursuit of unusualness, originality and madness of ideas, simple residential buildings in projects and implementation turned into real space objects.
Sometimes the embodiment of the wild imagination of the designer did not have a single recognizable architectural element - there is no roof, walls in their classical sense, too ... And at the turn of the century, the fashion for such buildings began to decline sharply - rather because of the irrationality of the constructive solutions themselves.
But humanity has benefited from this a lot: for example, with a light heart, they moved away from the unchanged classics of roof construction, taking note of new rational ideas. As a result, they began to build really beautiful, albeit unusual, roofs of private houses. For example:
Such a builder achieves much more efficiency from his creation than if he built an ordinary two-storey house under a gable roof. Those. all the minuses were reclassified as pluses, and the originality remained at its best:
As modern architects have calculated, the arrangement of just one corner above 45 degrees significantly reduces the unused area of \u200b\u200bthe house. And it's worth a lot.
You will be surprised, but in fact, the asymmetric roof is not so new. Even the ancient builders did not have in their arsenal modern computer programs and precise measuring instruments, as well as sufficient knowledge of stereometry. Therefore, they did not think for too long about how perfectly even the roof still needs to be made.
They used a long slingshot as the main measuring tool, and tied a cord and a plumb line to its ends. The slingshot was raised so that the plumb line pointed just to the middle end wall the buildings. Next, the ends of the cord were stretched to the corners of the house. If necessary, the slingshot was raised higher or, conversely, lowered lower. As soon as the overhang was chosen, a special board was nailed to the wall of the house. A cord was attached to these harnesses. So it turned out a clear visual boundary of future roof slopes.
Difficulties arose just with the second slope of the roof. The fact is that it was difficult to place the second board at the same height as the first one, because for a long time in Russia houses were built from roundwood. It is almost impossible to distribute such walls in one plane to the horizon. Therefore, transferring the size of one board to the second was hopeless.
For more accurate measurements, a water level was already needed. Only with the help of this tool, the horizon of the future roof turns out to be relatively even, and the ridge is placed in the center. But in most cases, especially when the construction took place in a remote rural area, the locals were not spoiled with such tools, and therefore almost everything was done by eye. And yes, the slopes at the roofs were often really different.
What is even more interesting, a truly asymmetric pitched roof was found in Ancient Rus' and as a separate specific type of architecture. Basically, these could be seen in wooden houses and palaces that belonged to rich people. Then it was with the help of architecture that the importance of the wealth of the owners of such buildings was conveyed:
Therefore, local architects of that time were looking for all the ways to make the same tower differ from a simple hut. Here it was already customary to cover each log house with a separate roof, even if the buildings were built by a friend from a friend.
Each ramp was guided and wrapped in a special way, with the help of a variety of possible completions. Moreover, the log cabins themselves were built of different heights, from which the roofs were often noticeably uneven.
But we note that the often encountered razor-sloped roof, in which the slopes do not converge in one ridge from above, cannot be called a gable. It is rather two separate shed roofs, which are built separately and each according to its own rules.
What is so good about an asymmetric roof that for the sake of its benefits, many are ready to risk both the strength of the house and the durability of the roof over their own heads? Let's list them.
The asymmetric roof always looks stylish in any terrain. In our country, after so many centuries of constant construction of towed gables, any such projects are already striking, surprising and leaving an indelible impression.
Moreover, if you want to create absolutely unique architecture at home, then it is easiest to realize your crazy idea just with the help of such a solution as different slopes.
Note that working with an asymmetrical gable roof is more pleasant and interesting for any architect. After all, now he does not need to first draw the contours of the house - a typical rectangle, and only then fit there everything that he and his customer planned. Now there are no frames: first you design the interior space of the house, make it the way you want, and the shape that your fantasy suggested to you.
Now you place a garage, and a veranda, and any gazebo near the house, and you will not need to worry about building all this on more than one foundation and attaching different roofs. Now, when your project is ready on paper, you simply draw a roof on top so that it covers everything.
And many more valuable advantages:
Most often, an asymmetric roof is built when the second floor of the house is planned to be incomplete. For example, the area of the first floor is 120 square meters, and the second - only 60. In this case, the roof closes only two or three rooms of the upper floor, and the rest of the space remains open.
Why is such construction good, and why is such a project attractive? First of all, the fact that there is already much less pressure on the foundation of such a house than that of a full-fledged two-story building. And at the same time, the foundation itself no longer needs to be built too wide, designed for extra square meters.
Often, an asymmetric roof is also used to install any necessary equipment such as solar panels.
A pitched roof is good because with the help of such a design, problems with strong winds and snowfalls. The fact is that if almost the same wind direction prevails in a certain area, then it makes sense to build a pitched roof so that it has a gentler slope on the windy side, and steeper on the quieter side.
This approach solves the problem of distributing the load from wind and snow at a time, while it is usually difficult to decide whether to make a gabled roof, thus getting rid of tons of snowflakes, or flat, so that it does not blow off in the first storm.
The fact is that a typical attic under an ordinary gable roof is the most losing and looks unpleasant, even psychologically pressing. It's all about the geometry of the interior: the incomprehensible dark space under the very ridge completely deprives the impression of the attic as a living space, and the sharp slope of the slopes and sharp corners certainly do not give comfort.
Of course, modern designers are enterprising and cunning, and have already learned how to use all these shortcomings for good, arranging wardrobes, and organizing such a space as something profitable and stylish. If you look at such a ready-made interior design of such an attic, the so-called “wow effect” immediately arises and it seems that living in such an attic is a real pleasure.
But in fact, all this is mostly beautiful - only in a glossy picture, but in real life such an attic, as it turns out, has too little usable area. Therefore, a gable roof with different slopes is a much more optimal solution. Especially the roof, which has a displaced ridge.
In this case, the geometry of the attic is no longer so unusual, and one of the walls may well be even vertical if you lose some half a meter of sharp space under this slope without regret:
Some architects even recommend building for attic houses asymmetrical roofs, namely, gable roofs with different slopes. So that the cornice would move forward and be a separate expressive architectural device. But, note, a gable roof with different slopes in 90% of cases is really built without an attic.
In fact, on the scales you have two aspects:
Therefore, decide for yourself what is more important for you: uniqueness or simplicity, and whether you are ready to make a detailed drawing for many long hours, calculate every little thing and risk, in fact, the whole building if you do not have enough experience. But in order to be proud of yourself and have extra comfortable space in the house. Let's just say: in this regard, modern developers are becoming bolder and bolder!
Note that the classic gable roof is the simplest constructive solution. Let's highlight the main types of different pitched roofs:
For example, modern houses of the Solomon project are distinguished, first of all, by the fact that they have a gable roof with different slopes. And the very design of residential buildings of the Solomon type is good because here you can make your own changes, refine the design and architecture of the house.
As you may have guessed, if you build a gable roof with different slopes, the architect does not have much choice: the slopes are the same, but at a different angle, the slopes are different in length, but at the same angle, their variations and the variant with an offset ridge. And each of these projects has its own advantages and disadvantages, which we will discuss separately.
In this example, the slopes have the same length, but are located at different angles: one is higher, the other is lower. This was conceived in order to place a spacious terrace on one side of the house, and a small utility block on the other. If the entire roof were as shallow as one of its slopes, then the owners of the house would have problems with the accumulation of snow. But the hozblok usually does not require a high ceiling.
Note that this option is the most sparing for designing a pitched roof and it almost does not exert different pressure on the foundation. And here's how to build a gable roof with different angles of inclination of slopes of the same length:
The only disadvantage of this option is the design. Believe me, it is much easier to calculate the slopes that are at the same angle of inclination, and it is much easier to attach them to the ridge.
In this embodiment, one of the slopes is slightly or significantly longer than the other. Like in this example:
Here one of the slopes is much longer than the other, thanks to which the roof covered not only the house, but also the adjacent veranda. And at the same time, the long slope itself relies not only on the house, but also on the extension, due to which the balance in the load from the roof is maintained.
Here's another one good example the construction of such a roof, however, a longer slope here no longer covers the extension, but part of the house itself:
Another project:
But in this project, the roof of the house on one side has the same slopes, and on the other it is already different:
But this option is more rational in terms of evenly distributing the load on the walls of the house, because thanks to the break, there is no longer one bursting force of the truss system:
Please note that under refraction, such a roof has additional props. And keep in mind that any breaks are always the most problematic places on the roof.
Such pitched roof projects no longer belong to those listed above due to their non-standard. But these are rare:
In this project, the whole point was to make a stylish and unusual room second floor. Interesting idea, don't you agree? Such cut floors exert half the pressure on the foundation, and therefore much less money needs to be spent on its construction (as well as on heating the whole house). And the foundation, as you know, costs at least 30% of the cost of building the entire house in the estimate.
And another project as an example, with one broken slope:
It’s already more difficult to deal with the skate, but everything is doable:
But it is especially necessary to carefully design the load from a displaced ridge on a timber structure. After all, the walls settle quite strongly in the first year, up to 15%, and therefore it is important to prevent the entire roof from skewing later:
So, as you already understood, a roof with different slopes is quite complex in its structure. Why is that? The fact is that such a roof rarely has a ridge in the center and, as a result, the slopes do not transfer the load evenly. That is why the architect, when working with such projects, has to carefully calculate the truss system, and with completely different formulas than usual.
So, for example, the central load will no longer come from the ridge itself, and therefore the subcortex will have to be placed a little to the side. But, at its core, the asymmetric gable roof still consists of two triangles - only this time they are not the same.
But this roof geometry also has your formula. Therefore, if you want to change something in one of the triangles, the changes will occur in the entire asymmetric roof. Keep in mind that when building such architectural delights, you will not be able to try everything on by eye. And even more so, then you will not make any changes.
So how do you still independently calculate and build an asymmetric gable roof? You will be helped by modern computer programs that are able to calculate the required pressure of the rafters on the Mauerlats and the exact location of the necessary central support. It will be difficult to calculate all this on your own, although it is possible.
So, if we are talking about a symmetrical roof that just has different lengths of slopes, then keep in mind that the slope that is longer has more pressure on the entire truss system and on the wall of the building. Due to the fact that it took more building material and more roofing. Usually for strong walls of the house this does not play a special role, but if you are building frame structure or block walls, create an additional support for such a slope, for example, almost at the very eaves.
Just remember that a roof with different slopes is calculated using different formulas. In fact, here you will need to make two whole calculations of two shed roofs, which are simply connected together with one ridge.
What we have listed is not the only option for building multi-pitched gable roofs. In fact, today architects no longer adhere to strict rules about such design and are more free to let their imaginations run wild. Why are they valued as professionals?
Our main task is to ensure that your home is securely sheltered from precipitation and cold. And all this is achieved with the help of a well-thought-out design, and it does not have to be standard at all, like a hut or a teremok. Despite the fact that the pitched roof is a little far from the design of the classic gable roof, its truss system must also be carefully calculated.
Particular attention should be paid to the loads and their correct distribution on the walls of the building. After all, the main mistake in private construction is when the roof is designed unusual, and even its ability to withstand wind and snow is calculated correctly by home craftsmen, but the roofing is not included in the load.
What does it threaten? So far, there are not so many implemented projects with pitched roofs in our country, and therefore it is difficult to track what exactly happens to such houses in 20-30 years. There simply is no such experience. But we can assure you that there have already been cases in world practice when the load from the roof was calculated incorrectly, and as a result, the building simply collapsed over time, not to mention serious distortions. We don't want this, do we?
And this is work with drawings and computer calculations. After all, it is important to make sure that the new roof perfectly withstands any loads and is stable both during heavy snowfall and during winds.
Note that today some architects are categorically opposed to the construction of a gable roof with different slopes. All due to the fact that for more than one century a gable roof in Russia was almost the only form. Today, for many professionals in their field, when it comes to the roof, symmetry is the defining element.
In the roof, they want to see unambiguous forms and clear lines that come together at the top. Note that such a smart classic gable roof is also perceived as more comfortable and more familiar, which is why customers themselves often refuse unconventional projects.
But for the more advanced architects of our time modern roofs are, first of all, new technical solutions. They are designed to improve such indicators of private construction as reliability, durability and functionality. Therefore, today the priority in terms of roof construction is not tradition and ideal geometry, but saving building materials, originality, which is now so lacking, and the most efficient distribution of useful living space.
You just decided to build your own house on suburban area Are you looking for a custom construction project? Then you should think about an asymmetrical or asymmetrical roof. From standard roof this design is different in that it has two slopes of different lengths or with a different slope. The gable roof of a building with different slopes is usually equipped when combining a residential building with some additional extension.
In this article
A similar question is asked by novice builders. Choice roof structure is based primarily on performance characteristics and appearance.
If you wish to build beautiful house, unlike the neighboring ones, the design of the roof must be taken into account already when creating a construction project. Symmetrical buildings have long become boring to everyone, modern tendencies design building structures suggest distortion of stereotypes, regular geometric shapes.
Therefore, a gable roof with different slopes effectively stands out among symmetrical counterparts. The ability to change the parameters of the classic triangle provides scope for creating original projects of gable roof structures. It also allows you to highlight the house against the background of neighboring structures, to draw attention to it, since it is the roof that sets the appearance of any structure.
Technological features of the roof structure are also based on its geometric shapes.
Important! The roof slope with the smallest slope is installed from the side of frequent and strong gusts of wind. This allows you to significantly reduce the load transferred to the supporting structure, reduce the noise effect from vibration roofing.
Increasing the angle of inclination of the slope of the asymmetric roof provides an opportunity to profitably use attic space, For example:
One of the most common ways to increase the area is the use of broken roof structures, when the angle of inclination of the roof slope changes without reaching the base. Of course, these are additional costs for building materials, and the installation of the roof is somewhat more complicated.
When performing calculations for a gable roof with different slopes, the following points must be taken into account:
Important! Roofing forms constant force effects on the elements frame structure. Therefore, when harvesting consumable lumber to create a frame, it must be taken into account that ceramic tiles much heavier than soft roofing materials.
All these nuances simultaneously create General requirements to the rafter system:
According to the finished drawings of a gable asymmetrical roof, you can read what elements are needed for the construction of the supporting structure:
A gable asymmetric roof is a bold solution for a country house, arranging your own home with a capital roof structure, which makes it possible to make the most efficient use of the free space under it.
A gable roof is a roofing structure that is most often used in private housing construction. It is not only easy to build, it is reliable, it will be inexpensive if you correctly calculate the number of elements .. The article discusses what elements this type of roofing consists of, and how you can assemble it yourself. You will learn about the basics of calculations, rules and assembly steps, which will allow you to talk on the same wavelength with the contractors of the construction company.
To find out the approximate cost gable roof use the following calculator:
From the name itself, it becomes clear that such roofs have only two slopes, which can be the same or different in area. The former are called symmetrical, the latter asymmetrical.
Not all gable roofs consist of the same elements. But there are among them the main ones that are present in all designs.
Mauerlat- a beam of 100x100 mm (minimum cross section), on which the rafter system rests. The main purpose is to evenly distribute the load acting from the side of the roof structure on the walls of the building. They attach the Mauerlat to the walls (there are several options).
rafters, otherwise they are called rafter legs. These are boards (rarely beams) with a minimum thickness of 50 mm, located with a slope towards the walls. They form slopes. The lower end they are attached to the Mauerlat, the upper end to the ridge beam or to each other.
Skate bar it is not always used, but only when the roof is covered with layered rafters. More on this below. Its purpose is to support the rafter legs.
Rafters attached to the Mauerlat Source krysha-expert.ru
Additional wooden elements that are not used on all gable structures.
Skate support. They are installed only if there is one in the roof structure.
Rafter racks. They are used if the width of the building is more than 12 m. The longer the rafters, the lower they are load bearing capacity.
Run, he's a beam laid on racks across the rafter legs. The rafters rest on it, and not on the supports.
Sill- a beam located parallel to the run, only in the lower part. Rafter racks are mounted on it.
Puffs. These are bars, pull together paired racks (between themselves).
There are two of them: hanging and layered. The first variety, in which the upper ends of the rafters rest against each other, are fastened together. To increase the strength of the connection and the reliability of the structure, a puff is often installed between them.
The second variety is legs resting on a skate. They can also be tightened if the goal is to increase the bearing capacity of the entire system.
Attention! The functions of tightening for a hanging variety can be performed by a floor beam, on which the legs rest.
Hanging and layered rafters Source kayabaparts.ru
On our website you can find contacts construction companies, which offer the service of calculation, installation and repair of the roof. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".
The gable roof is assembled in different ways. Dependence - type of truss system. Let's deal with each separately.
There is a strict sequence of operations:
Produce mounting mauerlat on walls. It is attached to them with the help of studs, which are installed in a poured reinforcing belt. The upper end of the stud is a threaded part onto which a nut with a wide washer is screwed. It is with them that the Mauerlat is pressed against the wall.
Produce ridge beam installation. To do this, along the roof structure right in the middle (if a symmetrical roof is being built), support posts made of timber or boards are installed. They are attached to the bed or to the floor beams with special metal corners for self-tapping screws. Additionally, supports and struts are installed to withstand the verticality of the racks.
For the last ridge beam is laid, which is fixed to the racks with the same metal profiles (corners, plates, etc.). The main task of the work foreman is to set the ridge run in a horizontal plane.
Rafters are installed in pairs, forming triangles of the roofing system.
hanging rafters Source kayabaparts.ru
If necessary, then under the rafter legs are installed additional racks. They are attached either directly to each other, or laid on top of the racks, a run across the legs.
over the truss system crate is installed from wooden blocks or boards.
Over the crate stuffed roofing material.
The sloping truss system of a gable roof of a frame house, and not only a frame house, is assembled not on the roof, but on the ground. The thing is that it is difficult to fit the elements together when they do not have support at one end. To do this, it will be necessary to build an additional supporting structure temporary type. This is a waste of time, effort and money that no one needs.
Therefore, paired rafters, they are in assembled are called farms, are collected in the plane of the earth. Since the truss structure is a triangle, in a symmetrical roof it is also isosceles, it will not be difficult to assemble it. The main task of the work foreman is to comply with the dimensional parameters of the truss elements. Because it will be more difficult to adjust roof trusses if there are sufficiently large dimensional errors between them.
Raise the rafter assembly to the roof crane or other device.
Installation of layered rafters Source pallazzo.su
At first install two end trusses along the gables of the house, put them together in height and fix them to the floor beams with supports and jibs (temporary).
A thread is pulled between the upper points of two trusses, along which the rest of the rafter triangles are mounted.
The rest, as in the case of hanging rafter legs: crate and roofing material are stuffed.
The process of erecting a gable roof in the video:
An important preparatory measure, on which the bearing capacity of the system as a whole depends. It is impossible to independently carry out the calculation if you do not understand this. Therefore, ordinary people use online calculators or tables. The calculation manipulations are based on the section of bars (in mm) or boards, depending on the length of the legs and the installation step.
The dependence is as follows: the longer the legs and the greater the distance between them, the larger the section of the beams should be. Eg:
installation step 2.15 m, the length of the rafter is 3 m; for this, a bar with a section of 100x150 mm is used;
step 1.4, length 3, section 75x125 mm;
step 2.15, length 5 m, section 100x250;
step 0.9, length 5.5, section 50x200 mm.
For each position there is a parameter of the applied bars. The tables are freely available.
Rafter legs distribution scheme Source chaos-heart.ru
Determining the slope of a gable roof structure is not easy. Consider the type of roofing. The dependency is like this:
if asbestos-cement slate is used, then the angle should be not less than 22°, a decrease in this parameter will lead to leaks at the joints of adjacent sheets;
metal tile - 14° angle;
corrugated board - 12°;
shingles- corner must not exceed 15°, otherwise there is a possibility of slipping of the coating from the crate;
roll material(roofing material, roofing felt and others) - slope within 3-25°.
But there is one nuance here. The steeper the roof, the less stress acts on its slopes, because rainwater and the snow quickly disappears from the surfaces. But at the same time, the windage of the structure increases. That is, wind loads increase. At the same time, high roofs mean an increase in the cost of building materials, which increase the cost of construction.
The angle of the roof slopes Source arhplan.ru
A gable roof with different slopes is quite common today. It cannot be said that they are better than symmetrical ones, but the originality of the design made them popular. We add that such roofs are more complex than traditional ones with the same slopes.
These roofs are divided into three kinds:
Asymmetrical. They have a ridge run located in the middle of the house. The slopes are located to each other at the same angle of inclination. But one of them is always longer than the other.
Asymmetrical. The slopes can be the same or different in length, but the angle of inclination of both is different.
Asymmetrical offset. The same as the previous version, only the ridge run is offset relative to the middle of the house to one side.
Asymmetric gable roof with offset ridge run Source pinterest.ca
A gable roof with different slopes is a difficult construction. The whole difficulty lies in the fact that the displacement of the ridge beam relative to the middle of the building creates completely different loads. They are no longer distributed along the ridge. Their main pressure (central) falls on a long, gentler slope. That is why at the design and calculation stage it is necessary to accurately determine the installation location of additional racks. They are installed under the rafter legs of a long gentle slope.
At the same time, they do not carry out the installation of the entire truss system by eye. Even the smallest deviation from the project can lead to irreparable consequences. Making changes to the design will be difficult, and sometimes simply impossible.
Asymmetric roof truss Source builtec.info
And one moment. An asymmetric roof (gable) requires the construction of a very strong Mauerlat, with which uneven loads will have to be redistributed. Special attention fastening the Mauerlat to the walls of the house.
As for the construction of a roof with different slopes, the technology itself is no different from the traditional one. The main thing is to strictly adhere to the requirements outlined above. Typically, such structures are assembled from layered rafter legs with the installation of a ridge beam. Therefore, the main task of the work foreman is to accurately set the skate horizontally on the site strictly according to the project. Be sure to accurately maintain the dimensions of the rafters, mainly in terms of length.
Another type of roof with two slopes. To understand what we are talking about, look at the photo below.
Multi-level gable roofs Source moscow.sk-evrodom.ru
In its configuration, the roof is gable, covering the entire house. But individually, each slope is shed construction. Usually a load-bearing wall is erected between them, on which both slopes rest.
But at the same time, a larger slope rests on the upper end of the wall, where a ridge beam or Mauerlat beam is installed, and a smaller one on its vertical plane, where it is usually fixed bearing beam. The construction of such roofs is carried out according to the technology of a shed structure.
These structures are mainly used in houses where an attic is planned. Organizing a room under traditional slopes is problematic. The reason is the presence of "dead" zones at the junction of the rafter system and the wall of the house. To remove these zones, it is necessary to make part of the slope steeper in terms of inclination relative to the vertical.
In cross section, the roof will not be triangular, but pentagonal. It is not easy to assemble it, there are too many elements located at different angles. But she has serious benefits before everyone else:
withstands well snow loads ;
resists well wind pressure.
Minus one - a large consumption of building materials. But the gain is clear - additional living room for little money.
Broken mansard roof Source nkkconsult.ru
The construction of a mansard roof is the installation of racks on which the beds are laid and the lower ends of the truss system rest. At the top, the ends of the rafters are connected on the ridge. The steep lower rafter legs rest against the Mauerlat from below, and from above to the beds. It turns out quite stable and durable construction.
In this video about the mansard roof device:
A variety of roofs with two slopes makes it possible to choose the option that will fit into the architecture of the house being built. The effectiveness of the building is just visible part. The design is based on the exact calculation of the elements and the loads on them. But, as practice shows, most of the roofs in the category of private housing construction are gable.
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. The starting material for the first option is a board, log, timber.
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 a welding machine and welder skills.
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:
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 roof 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 gable roof truss system, and it can involve either hanging or layered rafters, or a combination of both types.
Fastening the truss system to brick, foam concrete, aerated concrete walls is made through the Mauerlat, which in turn is fixed with anchors.
Between the Mauerlat, which is a wooden frame, and the walls of these materials, a waterproofing layer of roofing material, waterproofing, etc. is necessarily laid.
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.
Roof frame rafters wooden houses rest on the upper crown or on the ceiling beams. The connection in all cases is made by cutting and duplicated with nails, bolts, metal or wooden plates.
It is highly desirable that the cross section and linear dimensions of the wooden beams be determined by the project. The designer will give a clear calculation justification for the geometric parameters of the board or beam, taking into account the entire range of loads and weather conditions. If available home master there is no design development, 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, optimal distance there will be 0.6-0.7 m between the rafters, and 1.5-2.0 m is acceptable for the profiled sheet.
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 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:
The minus of the scheme is the presence of structural elements that affect the layout inner space operated attic.
If the attic is cold and organization is not supposed to be in it utility rooms, then the layered design 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:
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:
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.
Characteristic features of hanging type truss structures:
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.
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. its lower part should not come into contact with the puff at all. And the installation of racks as supports in hanging systems ah does not apply.
The bottom line is that the headstock, as it were, hangs on a ridge knot, and a tightening 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, strut beams complement the headstock. 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.
In order to increase the 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.
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:
Saving on the grade of material will not work. For load-bearing elements both systems: rafters, girders, 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 harvested on 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.
