The truss frame sets the geometric and operational parameters of the pitched roof. Due to violations in the installation technology, due to flaws in the manufacture of its elements, distortions of the system, traditional leaks, holes in the coating appear, threatening emergency situations.
In order to build a reliable and stable roof structure, you need to clearly know how the sawing and installation of rafters is performed, followed by fixation to the supporting elements.
Rafters, or rafter legs, are wooden or metal beams installed on the house box at a given angle. They determine the configuration of the roof structure, take on and steadfastly resist the sum of permanent and temporary loads acting on the upper enclosing system of the building.
The structural simplicity of the rafter legs is extremely deceptive. In fact, these are quite complex elements that require careful marking and accurate cutting. Inconsistencies in the connections of the rafter legs with the Mauerlat, with each other and other components of the system lead to a change in the shape of the slopes, a violation of the integrity of the coating and the destruction of nodes.
On the other hand, the competent installation of rafter legs can correct some errors in the construction of the house box, and not aggravate the situation by clearly repeating and increasing the wall height differences. True, in such situations, the frame elements are made individually and scrupulously adjusted in fact directly at the facility.
However, before dealing with the specifics of installation, you need to find out what their design differences are, according to which the rafter legs are divided into two groups, these are:
The scope of their application and installation technology depend on which group the rafter legs belong to. The hanging variety is collected on the ground, and the trusses, made in the form of peculiar triangles, are raised to the roof and mounted in a form completely prepared for installation.
The advantage of building a truss frame using hanging technology lies in the safety of work and the ability to perform nodal connections as accurately as possible. If the simplest version of a hanging truss with a puff at the bottom is used in the construction of the roof, you can abandon the Mauerlat device, in place of which a narrow leveling board is quite suitable.
The disadvantages of hanging technology are accompanied by advantages. For example, a truss assembled on the ground is much more difficult to transport to the installation site than boards and timber for layered rafters. There are restrictions on the spans to be covered: the limit is 14 m, above which it is unreasonable to install wooden beams prone to sagging without intermediate supports.
The rafter legs of the layered group both top and bottom are based on independent structures. The top of them is laid on a purlin structure, which is mounted on the floor beams or on the bed, replacing the Mauerlat on the inner wall. The bottom is either installed on the Mauerlat, or rests against it, catching on the bar with a tooth or a support bar sewn instead of a tooth.
The advantage of layered systems is rightfully recognized as the possibility of overlapping almost any span in size. It’s just that with an increase in the overlapped space, the design becomes more complicated: it is supplemented with struts for a couple with racks, additional runs, coupled with beds, fights.
The layered structure is assembled and mounted longer, because. it is built not from farms, but from individual elements. However, just this scheme has more opportunities to correct the shortcomings of a box or an unevenly settled log house. Because layered rafters are stacked individually, it is possible to slightly change the position and size of the node, in order to eventually form a perfectly aligned slope plane.
It is clear that for the construction of the truss system, lumber will be needed - long-length products of timber processing enterprises with clear geometric parameters. You will need a board or timber, on which, of course, there are no mounting cuts and cuts for installation.
Why are cuts and cuts needed? The fact is that when placed on an edge, boards and beams have too little support area. They are in contact with the Mauerlat with only one vestma in a thin line, because of which, at the slightest load from above, they can tritely “move out” from their position and drag the entire structure with them.
In order to increase the area of \u200b\u200bsupport in the junction of the rafter and the Mauerlat, or it and the additional run, a corner cut is selected in the beam or board, a tooth is cut out or a support bar is sewn on. If the top of the rafter is paired with a mirror-opposite counterpart, then for a reliable stop, you will need a gash, the plane of which must be clearly perpendicular to the horizon.
The basic rule in the construction of truss frames is that the support sites selected in the lumber are strictly horizontal and vertical. At the slightest violation of horizontality with verticality, stability is lost, structural parts are displaced under their own weight and load, up to the complete destruction of the system.
Note that the nodes of the truss systems are entrusted with the obligation to ensure the possibility of a slight displacement and rotation when the load is exceeded. These movements are necessary in order for the structure to bend slightly, move slightly, but not collapse and maintain stability.
These subtleties should be known both to the master who decided to do the manufacture and installation of rafters with his own hands, and to the owner of the house under construction, who does not want to pay for the poor-quality labor efforts of the builders team. Let's analyze the common options to understand the essence of the process.
Consider an example of the construction of a truss system over a log cabin of a bath. The span between the walls is small, it is easier and more reasonable to block it with a hanging structure, the installation of which will be carried out on the bypasses of the ceiling beams - matrices.
The log base is an almost ideal option for installing hanging systems, because. it is easiest to cut it into the horizon, eliminating the need to adjust the rafters in case of a violation of the geometry of the foot. There is no need for a Mauerlat device. However, the puff will have to be moved up in order to bypass the upper crown of the log house and form a useful attic space.
Before performing the installation of the rafters, a phased preparation of the log house is carried out. On both sides of the foot, we align the bypasses according to the lace tied to the nails hammered into the two extreme beams. On top of the bypasses, we cut off the slab so that the edge of each beam ends with a flat horizontal platform.
The surface formed after squeezing the upper bulge of the log along the edges of the beams is aligned to the horizon according to the level. We apply the specified control tool to three or more beams at the same time. If the level is not long enough to carry out such a check, use a long rail or board instead.
After squeezing all the excess, we mark the nests for the rafter tooth. To do this, we again use nails and lace. Note that it is possible to draw nest sampling sites on the bypasses both before the construction of hanging trusses and after. However, it is much more convenient to make nests before making rafters. They will help to carry out the fitting with higher accuracy.
To facilitate your work, it is advisable to find the center of the log house from the side of future tongs. At these points, it is recommended to nail along the control rail, one of the edges of which will indicate the axis of symmetry. You can do without rails if you already have some experience in the construction of roofs.
If everything turned out exactly and no more adjustments are required, the template is ready. We return with him to the ground. We disassemble the workpiece and make cuts along the marked lines. The parts obtained as a result of fitting and fitting will serve as a standard for the practically in-line production of roof trusses in the required quantity.
We will assemble hanging farms on the ground. Their installation, as well as fitting, should be carried out by at least two people. One master simply can not cope with such work. The performer at the top will install the truss, and the second one will change its position according to the plumb line. The position of each leveled and installed truss should be fixed with temporary struts.
To increase the stability of the system, we will install racks under the rafters:
To ensure the rigidity of the hanging system, the truss trusses are connected by wind ties - boards, poles or slats nailed from the inside of the structure. On the outside of the truss frame, rigidity will increase due to the construction of the crate.
The rafter legs are attached to the matrices with 200 mm nails or angle brackets. In this regard, metal corners and plates with perforation for fasteners significantly lose to traditional methods. To the sidewalls of the rafters we nail fillies made of a board, the width of which is half the material used in the manufacture of the rafters.
The length of the filly should be 70 - 80 cm more than the designed width of the overhang. This distance is necessary for their reliable connection with the rafter legs. Fillies can be cut in advance, or without preliminary cuts, you can nail the trimmings of a narrow board to the rafters, and then draw up the cornice line. However, the first option is more convenient and economical.
In most cases, as in the example above, fillies must be partially buried in the mats bypass, for this:
Upon completion of the installation of all fillies in the last ones, we hammer in a nail. We pull the control cord and mark where to saw off the excess.
In the construction of a truss frame using layered technology, there is much in common with the installation of a hanging structure. The fitting is carried out in almost the same sequence, so it makes no sense to describe the actions twice. The main difference is in the methods of forming the upper node, because the tops of the layered rafters have a support - a ridge run.
If at the top the layered rafters are tritely based on a ridge run, they are laid either with a run, i.e. parallel to each other, or with a strictly vertical joint, similar to the docking of hanging legs. However, in most cases, they try to fix the upper part with a notch or a vertical cut with a tight fit to the ridge beam.
There are schemes according to which the layered rafters are based not on the ridge, but on the side run. In such situations, the top is formed according to the hanging principle, and the point of support on the girder is made out with a corner cut.
Let us analyze the most popular option in private construction for the construction of rafter legs based on the lower corner cut and on the ridge run through the vertical gash. Note that the maximum depth of the cut should not exceed 1/3 of the width of the board.
Option for marking with a construction square:
At the end, we draw the outline of the cornice overhang on the board, cut it along the outlined lines and use the rafter blank made by ourselves to saw the rest of the roof elements.
You can apply the described method without a building square and marking the parameters of the roof on it. It is enough to imagine the process in order to set aside the necessary distances with a conventional drawing tool. However, without experience, you can get confused in the calculations of angles and segments.
To help novice builders, a template has been developed with options for forming corner cuts. It will help you navigate the manufacture of rafter legs from the most common lumber in this area.
In cases of laying rafter legs with notches in the upper and lower parts, it should be remembered that the depth of both notches must be the same so that the roof slope does not change during construction work. Usually, for the device of two equal cuts, an auxiliary bar is used, the thickness of which is not more than 1/3 of the thickness of the board.
The rafter blank is then installed with an edge on the Mauerlat and on the run. The bar is applied on the side in the area of the lower and upper nodes to outline the cut.
If the cut is needed only in the lower part of the rafter, and the top will be based on the run with a cut, the board is installed at the bottom on the Mauerlat, and at the top on the run and the bar, so that as a result of cutting, the slope of the slope does not change. At the bottom, a second bar of the same size is applied to the future node and the outline of the future cutting is outlined with it.
The same methods are used to form cuts with a tooth. The difference is only in the form washed down.
The installation of layered rafters begins with the installation of two extreme trusses. The elements are mounted one at a time, their position is carefully checked using a plumb line. Most often, extreme farms are arranged from paired boards, because. they carry more load. They are fixed with temporary spacers, then connected with a cord or rail to indicate the plane of the slope.
Ordinary rafters located between the extreme load-bearing trusses are installed according to the instructions of the laces. If necessary, correct the position of the legs according to the actual situation.
Installation of rafters with fastening with metal corners:
How to make rafter legs with cuts for landing on a Mauerlat:
The device of the truss frame under the roof of the garage:
We have given and described only a part of the methods for constructing truss frames. In reality, there are much more manufacturing and installation methods. However, an analysis of the basic options allows you to perfectly understand how to properly make rafters and truss trusses for the roof, how to saw them down before installation.
The truss system is the roof frame, which is the basis for the roofing decking.
The rafter system is designed to withstand the load of the roof, taking into account natural loads: winds, snow, rain.
The roof option is approved at the design stage.
The purpose of the roof includes several functions: warmth in the house, protection of the premises from natural phenomena, therefore the truss system must be given special attention.
You can read how to calculate the truss system.
It is customary to classify truss systems so that the task of choosing a variant of the future roof is easier to solve:
The most suitable designs for - and broken gable. There are others, but they are less common and not as practical as those listed above.
Rafter structures are also classified into:
The calculation of the material for the roof frame when designing a building is based on the intended configuration and load. Do-it-yourself rafters are not difficult to do, it is important to approach the matter wisely.
Rafter systems of layered and hanging type
To correctly calculate the load on the rafters, it is necessary to take into account many factors that can affect the severity of the structure.
Important metrics to consider:
In addition, you should keep in mind the mass and strength of the rafter legs, as well as pay attention to the fastening of the gable roof rafters and the installation option.
Scheme of truss systems
The rafter pitch of a gable roof is the empty space between the rafters. The functionality of the roof depends on the correct calculation of the pitch. As a rule, the step is about a meter.
For a more accurate calculation of the distance between the rafters, there is a certain calculation scheme:
This calculation is not always final.
Additionally, you should take into account the load of the roofing (its mass), the thickness of the rafters, as well as the dimensions of the rafters for a gable roof.
The thickness of the rafter board largely depends on the covering material:
All indicators should be taken into account and the thickness of the rafter should be accurately calculated so that there is no excessive load on the foundation.
Incorrect calculation of the length of the gable roof rafters, as well as incorrect calculation of the pitch indicators, can lead to sagging of the roof.
Do-it-yourself installation of gable roof rafters requires taking into account the weight of the rafter board and all additional structural fasteners.
Rafter construction - a complex system and installing a gable roof truss system is not an easy task. truss system consists not only of rafter boards, but also of other additional elements:
The rafter system implies rafters, stretch marks, braces and racks located in the same plane. They are located in such a way that the main load of the roof structure falls vertically on the external load-bearing walls. Therefore, the manufacture of gable roof rafters is a very important process.
What is the gable roof truss system
A layered rafter system is used when the span does not exceed 6.5 meters.
In the presence of load-bearing structures inside the building, it is possible to install additional racks.
The main support of the rafter legs is the Mauerlat.
Before mounting the Mauerlat, it is necessary to install an armored belt. It consists of a formwork in which reinforcement is laid and poured with concrete. At the base, with concrete that has not yet hardened, studs are installed, to which the Mauerlat is then attached.
Mauerlat - a beam that is laid on a support (bearing wall) and is the base of the truss frame. A layer of waterproofing material is preliminarily laid. If the length of the beam is not enough for the length of the wall, then it is increased.
The stability of the roof structure depends on how firmly the Mauerlat is installed.
Therefore, it is necessary to take seriously the fastening of the Mauerlat to the bearing support.
Mauerlat installation
After the Mauerlat has dried (after 5 days), the installation of the bed is marked on the Mauerlat beam: its axis should be with the same indentation on each side of the Mauerlat beam. The bed is attached to a two-layer waterproofing layer with anchor bolts. To the wall from the inside, the bed should be fixed with twists of wire or staples. Next, markup is made for installing the rafters.
The anchor points of the layered rafters are the walls and racks inside the frame. The rafters are mounted with hinged attachment points. When using sliders for fastening, a slight lowering of the roof frame is ensured in the first years of the roof's service life.
This installation method is necessary to prevent distortion, as in the early years the building settles a little.
Rafter beams should be fixed either by installing them in prepared grooves and strengthened with fasteners, or by attaching plank linings.
Installation of rafters
The rafters are joined end-to-end, cutting off the edge of the bar so that the angle when connecting opposite beams corresponds to the angle of the slope. Hammer the rafters under the ridge with nails. A variant is possible in which the beams are connected by bolts, a nail or a hairpin, that is, they overlap.
If necessary (if provided by the project), a cut is made in the rafter beams for attaching the ridge beam (purlin).
ridge knot
Racks are attached with a short span - in the center, on the sides and center - with a wider roof base. Fastening is carried out vertically from the ridge to the inner wall.
Run - a connecting beam for fixing rafter legs. Fastens with bolts or brackets to the rack.
The final step in the installation of the layered system is the installation of filly with a short length of rafter legs for overhang. To install the visor, it is necessary to install additional small rafter boards.
Installation of a rafter system with layered rafters
truss system, equipped with hanging rafters, is a triangular structure, where the sides are rafters, and the base is a puff connected to the lower heels of the rafters.
Installation of a hanging-type truss frame can do without installing a Mauerlat: a board that is fixed on a two-layer waterproofing can replace it.
If the structure has a large span, then struts, headstocks, crossbars are attached to it.
Racks in the hanging system are not provided.
The puff is the longest beam of the roof frame. To prevent it from sagging, it is necessary to fasten headstock - boards that are attached to the top of the structure on one side, and to the puff - on the other. Fasten with bolts or overlays made of wood. The slack can be adjusted using the threaded collars.
The device of the truss system
The headstock can be supplemented with strut beams, forming a rhombus, where two struts are the lower sides, and the rafters are the upper ones, the upper corner is the ridge. Thus, the struts rest against the headstock, distributing the load.
Strut beams
Rafters of a hanging structure are mounted like a layered one. When installing attics, the puff is installed closer to the ridge, providing more space under the ceiling. The tightening in this case is fastened by cutting with bolts.
ATTENTION!
When installing a hanging system, a prerequisite for installation is the accuracy of calculations and the strength of the rafters and puffs.
The presence of errors leads to the displacement of the axes of the elements of the system, which provides a distortion of the structure.
How to install rafters for a gable roof will tell you this photo:
Rafter installation
hanging rafters
It is necessary to reinforce the rafters of a gable roof when the load calculation is incorrect or frame defects are found.
Strengthening can be done with:
You can resort to strengthening the Mauerlat beam and the base of the rafter beam. Due to high humidity and reduced ventilation, these parts of the frame are more susceptible to decay, therefore, when arranging the roof special attention needs to be paid
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 to more complex designs that add a special appeal 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.
When arranging pitched roof structures, the truss system is a frame for covering and for holding materials of the "roofing pie". With proper installation of the frame structure, the necessary conditions will be created for the correct and non-insulated types of roofs that protect the walls and the interior of the house from various atmospheric influences.
The roof structure is also always the final architectural element of the 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:
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.
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:
In addition to the above structural details, 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 the different features of its design.
Before proceeding to the consideration of different types of roofs, it is worthwhile to figure out what an attic space can be, since many owners successfully use it as utility and full-fledged living quarters.
The design of 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 version. 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.
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 the goal of creating an exclusive original project, unlike the buildings standing nearby, it is necessary to familiarize yourself with the design and operational features of various truss systems and make 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 conjunction 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 process of cleaning and repair work on the roof will be carried out.
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.
The following materials can be used to cover the roof: either a 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.
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
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:
The lower edge of the rafter legs is attached to the Mauerlat with movable fasteners.
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 the overall structure of the 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.
To install a gable roof yourself, average carpentry skills and an understanding of its manufacturing technology are enough. All this is easy to understand. It is also necessary to involve an intelligent assistant in the process, because many operations cannot be performed by one person alone. Therefore, many without a doubt take up this work and successfully cope with it.
The construction of a country house is associated with considerable costs. Therefore, many people are looking for options to reduce the cost of this process through the use of modern materials and technologies. Currently, frame buildings with gable roofs have become very popular. This happens largely for the reason that even a person with minimal knowledge of the construction business, with appropriate preliminary preparation, can carry out such a design.
A gable roof is formed by triangular trusses connected to each other by a longitudinal upper beam (ridge run) and a crate
However, the construction of the roof is a crucial moment that requires a serious attitude. Need to calculate:
Without experience in the production of such work, you should not take on complex structures, but it is quite possible to build a small house with a simple gable roof with your own hands.
Such a roof consists of two inclined planes located at a certain angle. Gables are arranged along the end walls, which are a vertical continuation of the walls. In shape, they are isosceles or arbitrary triangles, if the slopes are arranged at different angles to the horizontal. In the case of a gable sloping roof, the gables are trapezoid-shaped.
When building a roof, a rafter system is created, which is the supporting element of the roofing pie. The rafter system can be made in the form of hanging rafters if there are no capital partitions inside the building box. If available, a floor frame is arranged when the span is supported by three or more points.
Depending on the design of the truss system, its main elements may be different, but the main details are present in all options:
In the process of designing a truss system, it is necessary to optimally place all the elements of the frame in order to ensure a uniform load on the roof over its entire area. The main types of load are:
Thus, it is necessary to find the optimal combination of these indicators with simultaneous exposure to wind and snow. Data on specific loads for the construction region can be found on the Internet.
Gable roofs with a simple design give the house an elegant and festive look.
The gable roof allows you to arrange a small attic room on the second floor. The slope of the gable roof is selected based on the intensity of the winds and the average snow load in the construction area.
Determination of the main characteristics of the roof is necessary already at the stage of designing the foundation to calculate the effect of the total weight of the building on the support base.
With a symmetrical gable roof, it is enough to determine the area of one slope and double the result.
The height of the roof depends on the chosen angle of inclination of the slope. Usually it is in the range of 30-45 degrees. In the first case, the height will be half the distance from the projection of the ridge to the Mauerlat axis. Using the Pythagorean theorem and after doing the calculations, we get that the length of the slope for a building of 10x9 m will be 5.05 meters. The slope area is defined as 5.05 x 10 = 50.5 square meters. And the total roof area will be 50.5 x 2 \u003d 101 m 2.
In cases where a gable roof has a non-equilibrium roof, i.e., the axis of the ridge is offset from the axis of the building, the area of \u200b\u200beach slope separately is calculated using the same method and the results are summarized.
However, this calculation does not take into account the area of the roof overhangs. Usually they are 0.5–0.6 meters. For one slope, the overhang area will be 0.5 x 5.05 x 2 + 0.5 x 10 \u003d 4.1 + 5 \u003d 9.1 m 2.
The total roof area will be 101 + 9.1 x 2 = 119.2 m 2.
The size of the cross section of the rafters depends on several factors:
All these parameters have long been calculated, and to determine the cross section of the rafter legs, you can use the data below.
With an increase in the installation step of the rafters, the load on each of them increases, which leads to the need to increase the cross section.
Common sizes of the main parts of the truss system:
The angle of inclination of the roof slope is determined by the requirements of its finishing coating:
One of the reasons for reducing the angle of inclination is the desire to make the attic or attic space as large as possible. This intention is also the reason for the installation of a sloping roof.
This parameter depends on the type of finish coating, or rather, its weight. For the heaviest material, the distance should be minimal, from 80 centimeters. In the case of using a soft roof that is light in weight, the distance can be increased to 150 centimeters. The calculation of the number of rafters and translations is carried out as follows:
With this distance, all rafters will be equidistant, and the load from the roof will be distributed evenly.
The length of the rafters is calculated according to the Pythagorean theorem, as already shown above.
Work on the installation of the truss system begins with the installation of the Mauerlat.
Mauerlat is made from high strength wood - oak, larch, etc. In the absence of such materials, pine can be used.
The bar is of standard length - 4 or 6 meters. Therefore, the connection of several parts along the length is inevitable. It is made with a gash of the connected ends “half a tree”, for example, for a bar with a section of 150x150 millimeters, a sample of 75x150 with a length of 300 mm is made. The ends are overlapped. Fastening is carried out with two or four screws M12 or M14 with the installation of washers of large diameter. By the same principle, the bars are connected at the corners. The finished structure is a regular rectangle, which is installed on the upper plane of the wall around the perimeter.
The Mauerlat installation technology provides for its placement strictly along the axis of the wall or with an offset in any direction. In this case, you can not place the support beam closer than 5 centimeters from the edge. To increase the service life, the Mauerlat should be installed with waterproofing on the wall surface. Most often, ruberoid is used for this.
The mounting points should be located approximately in the middle between the rafter legs.
The studs are immured into the wall during its pouring, then a Mauerlat is put on them and fixed with bolts. The wire is also installed at the stage of laying the wall. staples
The choice of roof truss design is determined by the configuration of the building. If there are no internal capital partitions, a hanging truss system is constructed.
In the presence of capital partitions, it is necessary to use a floor mounting scheme.
This is the name of a pair of rafter legs connected in an arch with the installation of a spacer element in the form of a puff for a hinged system or a crossbar for a flooring system.
Installation of truss pairs is carried out in three ways:
With any option, the rafter legs are mounted according to the template, which is the first truss. For higher assembly accuracy of the parts of the next pair, it is desirable to fix them to the previous one with clamps.
Prefabricated roof elements are installed in the following sequence:
For reliable connection of the elements of the roof frame, various auxiliary elements are used, made of galvanized steel up to 1.5 mm thick.
When assembling with the use of additional connectors, labor productivity increases and the strength characteristics of the structure increase.
To connect the elements of the roof of wooden buildings, special fasteners are used. So, the upper joint of the rafters is often connected using a hinge. This is due to the frequent movements of the building, including seasonal ones.
For the same purpose, sliding fasteners are used on houses made of this material.
Before installing the crate, the roof is insulated. For this:
Thus, in addition to insulation, a ventilation system of the under-roof space is created. It starts to work after the installation of the coating.
Under certain conditions, roof insulation can be done from the inside, it is not so convenient, but you can safely work in all weather conditions. The formation of the roofing cake is carried out in the reverse order. Each layer of insulation as the flooring needs to be strengthened in the openings between the rafters.
Before proceeding with the design of the pediment, you need to arrange the crate and lay the finish coating of the roof.
When forming the crate, the type of future roofing is taken into account. It is made from edged boards with a thickness of 25 millimeters. The crate happens:
The crate should be taken out of the gable rafters for the overhang device.
Before laying the crate, the roof is insulated and a moisture-proof layer is laid. Further:
When installing the finishing coating of the roof, you cannot save on fasteners; the protective layer must be durable, able to withstand wind and snow loads.
The crate of the frame gables is made based on the characteristics of the material intended for the front finish. For this, the following products can be used:
After installing the crate, it is necessary to lay a moisture protection from a polyethylene film 200 microns thick. It can be fixed with building brackets. This work is done outside. On the film, you can sheathe the outer surface with the selected finishing material.
Gables need to be insulated with rolled or tiled heaters. The thickness of the protective layer should be at least 10 cm, and for areas with a cold climate - at least 15 cm. An internal moisture-proof film layer is stretched over the insulation.
On top of it, a crate for the front finish is stuffed, for which bars measuring 50x50 millimeters are used. Finishing of the entire building is carried out simultaneously, after the insulation of the roof.
In the process of facing the pediment, windows are installed if they are provided for by the project, and in some cases doors.
Roof overhangs, both gable and cornice, except for a purely decorative function, are designed to protect walls and foundations from water or snow. Their sizes are usually 50-60 centimeters. Overhangs are made with various materials:
There are several ways to arrange overhangs:
Ventilation holes must be made along the lining. They can be of any size, but large ones must be covered with a fine mesh of any material. This avoids the penetration of birds and harmful insects into the under-roof space. Soffits are sold with ready-made ventilation grilles.
Ventilation is arranged only on cornice overhangs; it is not needed for gable ledges.
With the modern abundance of building materials and their quality, you can install a gable roof yourself. The cost savings will be quite significant. But it can also turn into losses if you do not carefully consider every step you take during construction. I wish you success!
The construction of the roof is one of the most important stages in the construction of a house. The simplest designs include gable roofs with straight slopes. If it is decided that a gable roof will be built with your own hands, then you need to carefully read the step-by-step instructions and video. The functional parameters of the roof also depend on the correct insulation, characteristics and quality of installation of the finish coating.
To determine the configuration and size of the roof, it is necessary to take into account the snow and wind load in the existing climatic conditions - the smaller the angle of inclination, the better the design resists loads. But a small angle of inclination (40 degrees or less) does not allow full use of the attic space.
The shape and design of the roof are developed in accordance with the design plan of the house: the key points of support of the roof truss system must coincide with the lines and points of location of the supporting structures of the underlying floor. Thus, it is necessary to take into account the width of the house, the presence of a longitudinal load-bearing wall in the center. If the attic is not planned to be used as an additional usable area for permanent or seasonal residence, a reliable roof with layered rafters can be made. In this case, the rafters are attached to the ridge run, which is supported by racks resting on an internal load-bearing wall.
Hanging rafters are the most practical and economical option for light structures. In this case, the rafter legs are connected in pairs with crossbars - horizontal lintels, which provide the necessary rigidity of the structure. The hanging rafter system rests on the side walls of the structure.
If the width of the house exceeds 6 meters, in addition to the crossbars, which act as the basis for the ceiling, runs and racks are installed. The run is a horizontal bar that acts as an additional support for the rafters that form the roof slope. Installation of the run requires the use of racks. Racks, in turn, rely on beds - a special beam laid along the slope. Beds and racks perform the function of the frame of the walls of the attic room. Such a layered design allows you to make an attic or a spacious attic for household needs with your own hands.
If the construction of a simple and reliable roof is required, a gable construction with an angle of inclination of 45-50 ° is optimal. Such a truss system is suitable for installation on residential buildings and buildings for various purposes. When calculating materials, it must be taken into account that the truss system must be light enough to avoid excessive load on the foundation, but at the same time strong. The cross section of lumber should be selected based on the dimensions of the truss structure.
Consider step by step how to build a do-it-yourself roof with layered rafters and an attic. At the first stage, the installation of the upper strapping - the Mauerlat - is carried out on the longitudinal walls of the house. The strapping takes on the pressure of the entire roofing system and evenly transfers it to building structures - walls and foundations.
Mauerlat is made of timber (section from 50 × 150 to 150 × 150 mm), treated with special protective agents to protect against decay and fire.
Mauerlat can be done in various ways:
Studs should be located with a step of no more than 120 mm. The height of the protruding end of the fastener should be 20-30 mm higher than the total thickness of the waterproofing and the beam, in which holes should be made in advance. The beam is put on the studs and tightly attracted by nuts with wide washers.
The truss system, which you can do with your own hands, consists of a number of elements combined into a single whole. The A-shaped truss truss is a rigid structure that works "for expansion". If the roof is being built on a timber house, the opposite walls should be reinforced with 100 × 150 mm timber couplers at the level of the ceiling beams. This is done so that the walls do not move apart under load.
Beds are laid on the ceiling - additional elements from a beam of 150 × 150 mm or more, which serve as a support for the racks and redistribute the point load on the ceiling surface. Do-it-yourself laying of beds should be done along the lines of the walls of the future attic space. If the attic is not going to be used, the bed can be laid directly under the ridge to mount support posts. If necessary, you can splice the timber, but only in places where the joint will lie on the beam. The spiked connection is reinforced with a bracket or a metal plate.
The repeating parts of the rafter system should be made completely identical to each other in order to build an isosceles gable roof, the weight of which will be distributed evenly even under atmospheric loads. For this purpose, templates of identical parts are made with their own hands.
Boards 50 × 150 mm are laid out on the floor of the house, a triangle of the required height is made from two rafter legs and a rack board (its length corresponds to the height of the future roof), connected by a nail. Together or three of us, the structure rises - the rack is installed on the central axis of the ceiling, the rafters are installed on the Mauerlat.
In the process of preparing the template, you can lengthen the elements by varying the height of the roof and choosing the most suitable option.
Having decided on the dimensions, it is necessary to make curly cuts on the rafters at the points of their contact with the strapping. The rafter leg should firmly rest against the Mauerlat. There are a number of mounting methods, you should choose the most convenient and reliable, it is advisable to use metal lining. The intricacies of the technology can be found in the video. The resulting truss structure subsequently acts as a template, and the support board helps to control the height of the installed trusses.
The pediment is a continuation of the wall, bounded by the slopes of the roof. If a gable roof is provided, the gables of the house are in the shape of a triangle. When installing the rafter structure, first of all, extreme trusses are installed, which later serve as a frame for the gables. It is necessary to strictly check the verticality of the structures and ensure that they have the same height. In the upper part of the gables, a ridge run is attached, to which the rest of the truss structures are subsequently mounted.
Usually the gables are sewn up after the completion of the roofing work, but this can be done at an earlier stage. Installation of boards 50 × 100 or 50 × 150 mm is carried out in a vertical or horizontal direction. The pediment, which you can build with your own hands, is often equipped with windows.
It is necessary to provide for the insulation of the gables.
A crate is stuffed onto the truss system, the pitch of which is calculated based on the characteristics of the roofing material - its size and rigidity, installation method. If the use of flexible materials (bituminous tiles, PVC films, rolled bituminous roofs) is envisaged, it is necessary to make a continuous, even flooring.
Roof insulation must be taken as carefully as possible, since otherwise heat losses will be very significant. Usually, a gable roof is immediately carried out taking into account the use of certain materials for insulation - when building a rafter system with your own hands, the pitch of the rafters is calculated relative to the width of the sheet insulation. This allows you to build a roof with minimal economic costs, since the material for insulation does not have to be cut. In addition, this approach speeds up and simplifies the installation of the insulation and vapor barrier system.
In this high-quality video, you can see in detail how to make a gable roof yourself and make sure that there is nothing complicated about it.
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