The roof, of course, is one of the most important structural elements of any building, including a low-rise private. When constructing a suburban residential building, a variety of types of roofs can be mounted. But most often on one-story buildings they erect gable structures of this type. Such roofs, in turn, can be simple or broken. Installation schemes for roof systems of gable roofs of various configurations and will be considered by us later in the article.
What is a
The construction of gable roofs is extremely simple. That is why they are very popular among private developers. Simple roofs of this type consist, as can already be judged by their name, of two slopes. The latter in this case have the shape of a rectangle and are located in the roof structure at a certain angle. The scheme of the rafter system of the gable roof of this variety is presented below.
Broken mansard roofs have a slightly more complex configuration. They have a slightly different design. There are also two slopes of such roofs. But a feature of such roofs is the presence of a kink. Each of the slopes of such a roof consists of two rectangular parts located at an angle. The scheme of the rafter system of the gable roof of the attic can be seen below.
To erect broken roofs on country houses, of course, is more difficult than simple ones. But at the same time, such roofs are more convenient in operation. The attic under such roofs has a very large volume. And on it, if desired, you can equip even one more additional living space.
Next, we present to the reader, for clarity, also a photo of the rafter system of a gable roof. As you can see, the design of such roofs is actually relatively simple.
The main elements of the rafter system
When assembling the frame of both ordinary and broken gable roofs, in most cases the following elements are mounted:
Mauerlat;
rafter legs ;
crate.
Sometimes a ridge board is also included in the construction of roofs of this kind. Also, in some cases, when assembling gable roof frames, racks, girders, puffs and struts can be installed. Such elements are usually used in the installation of roofs of houses of large area.
In the scheme of the rafter system of a gable roof with a bay window, if the latter is located on the side of the building, among other things, such elements as valley gates are included. Roofs of this type already have a rather complicated configuration. In any case, a beginner may not need to undertake the construction of such a roof. At the very least, it is better to entrust a specialist with the development of a project for the roof of a building with a bay window.
Material selection
We will talk about how to make a rafter system of a gable roof with your own hands a little lower. To begin with, we will figure out what materials will be required for the construction of such a structure. In some cases, the truss system of gable roofs can be assembled from metal elements. However, such materials for the installation of roofs are usually used only in the construction of various kinds of industrial buildings or small architectural forms.
The roofs of private houses in the vast majority of cases are assembled from boards and timber. The advantages of such structures can be attributed primarily to low cost and ease of installation.
Of course, lumber for gable roofs should be chosen correctly. For the manufacture of rafters, in most cases, a board with a section of 100x150 mm is used. Mauerlat is most often collected from a beam of 150x150 mm or 200x200 mm.
For the installation of the crate , a board is usually used with a width of not more than 15 cm. A larger material can become distorted over time under the influence of adverse weather factors. And this, in turn, will lead to damage to the roof sheathing.
In any case, lumber for installing the rafter system of a gable roof should be selected high-quality - 1-3 grades. Otherwise, the roof of the building will not last for too long. That is, it is necessary to use a timber and a board with a small number of knots for building a roof. Also, such material must be well dried. Otherwise, after a couple of years, the roof structures will warp, dry out and crack. As a result, the roof will have to be repaired or its roof system should be completely replaced with a new one.
Buy for the assembly of the roof should be lumber with a moisture content of not more than 12-15%. And even such a board and timber before starting work should be dried for several months in a shaded place.
Almost any type of wood can be used for roofing. In the construction of low-rise private houses for this purpose, cheap pine is most often used. Experienced masters do not advise choosing such boards longer than 6 m for rafters of gable roofs. For a Mauerlat, it is recommended that you use a solid wood beam. That is, a soft pine for installing this structural element of the gable roof frame should not be purchased.
Self-development of the scheme of the rafter system of a gable roof
Before proceeding with the erection of the roof of a country house, of course, you should do all the necessary calculations and draw up a project. The development of the drawing of such a design will allow to avoid various errors and unnecessary waste of material during its assembly. When designing a roof, you first need to determine the angle of inclination of its slopes. The choice of this indicator for gable roofs depends on what wind and snow load they will be exposed to during operation.
In regions with a large amount of average annual rainfall, in most cases rather steep roofs are erected. The slopes of such roofs are located at a significant angle. The snow from such roofs quickly slides and practically does not exert any load on them.
In windy regions, erect gently sloping roofs are erected. Such roofs practically do not sail. And accordingly, in the windy region, they can last a long time. The angle of inclination of the slopes of such roofs can be made quite small. However, it should not be less than 5 degrees.
The slope of the roof slopes is calculated taking into account the indicators of the wind and snow load tables. Almost throughout Russia, the optimal parameter for installing roof trusses is 30-45 degrees. This is how most owners of country houses erected roofs.
After performing all the calculations, a diagram of the truss system of the gable roof is drawn. When drawing up such a drawing, according to the standards, it is supposed to indicate the length and cross-section of all elements, as well as note the methods of pairing the nodes.
Mauerlat installation
Next, let's look at how the rafter system of a gable roof is assembled with your own hands step by step. First of all, when installing the frame of such roofs, of course, a Mauerlat is installed. This structural element of the roof truss system is its support and carries the main load from it. Mauerlat is laid on the walls of the box of the building being built from above. Fasten this element in most cases to anchor bolts. Such fasteners are pre-walled in masonry walls or in concrete of the upper reinforcing belt.
Mauerlat is not used only in the construction of paving and log houses. In such buildings, its role is played by the upper crown.
When erecting large-area rafter systems, Mauerlat elements are usually mounted on all four walls. On such buildings, roofs with a ridge are most often erected. And on the front facades, the Mauerlat serves as a support for the central gable pillars.
During the construction of roofs of small one-story buildings, the supporting beam is usually laid only on two parallel long walls of the box. In this case, the Mauerlat will perceive the load only from the rafters themselves.
It often happens that the beam selected for the assembly of the supporting frame of the roof frame has a smaller width than the walls. In this case, the Mauerlat is usually mounted closer to the outer edge of the latter. Before installing this element, the top of the walls must be laid with two layers of roofing material.
Rafters
Such elements serve in the construction of the gable roof truss system as a support for the insulating “pie” and the casing. In their manufacture, it is important to maintain the correct dimensions and geometry. Otherwise, the roof will subsequently turn out to be sloppy and will not effectively protect the interior of the house from adverse weather factors.
Cut rafters during the construction of gable roofs relies using a template. You can make such a device, for example, from some waste board. The length of the rafters of the gable roof is calculated quite simply. For this, the formula for a right triangle is used, in which:
The length of the rafters themselves in this case will be calculated as the length of the hypotenuse through the sine or cosine of the slope angle.
The rafters are located during the construction of the gable roof frame, usually in increments of 80 cm. Standard mineral wool slabs have such a width. With this arrangement, to mount this insulator in the subsequent, accordingly, it will be possible without cutting. The width of 80 cm is usually also standard attic purchase windows.
Step-by-step technology for installing a rafter system without a ridge
Such frames are equipped with self-construction of suburban residential buildings most often. They are called a hanging rafter system. Gable roofs of this type are characterized by maximum ease of installation and are considered reliable.
In the rafters when cutting in this case, most often:
Mount rafters cut according to the template, usually using the following technology:
establish two extreme trusses over both end facades of the house;
stretch a rope between farms;
focusing on the cord, mount intermediate farms.
Such a scheme for installing a gable roof truss system, among other things, requires the exact observance of the technology of fastening elements. Such connections should be as reliable as possible.
When installing the frame of a gable roof, the rafters can be attached to the Mauerlat rafters in several ways. Most often, these elements are fixed on a support beam using galvanized corners. But in some cases, the rafters can be fixed by means of a knot of three nails. At the top of the rafters are interconnected using steel galvanized plates.
Assembly of the frame with the ridge
Hanging roof systems of gable roofs can be quite strong and durable. But when erecting large roofs, still more reliable constructions with a ridge are often assembled. Such roofs are also mounted using a fairly simple technology. In this case, two end end support posts are installed first. Next, a cord stretches between them. Then intermediate racks are mounted. They are supported on previously laid floor beams.
At the next stage, a ridge board is attached to the racks installed in this way. Then the cutting and installation of the rafters is performed. In this case, the supporting elements of the frame are also mounted usually in increments of 80 cm. They are attached to the ridge using angles. Sometimes rafters are also displayed above this central board and fastened with steel plates. Often under the ridge the legs are additionally fixed using horizontal boards - crossbars.
One of the elements of the truss system of gable roofs of houses can be struts. They are placed at a certain angle between the racks and rafters. Such elements add rigidity to the roof frame.
Features of the installation of rafters on the roofs of wooden houses
On such buildings, rafters are installed using the same technology as on brick, block or concrete. However, they are attached to the upper rim using not corners or nails, but special elements called slides.
A feature of cobblestone and log buildings is that over time they give a strong shrinkage. With a rigid fastening of the rafters to the Mauerlat, because of this, the roof frame can subsequently become very distorted. The use of a slide allows avoiding the occurrence of such a problem. These fasteners, unlike the corners, have a movable part. Due to this, the rafters during shrinkage of the box just occupy the desired position.
Installation of a broken roof
The rafter system of a gable roof with an attic is erected, of course, using more complex technology. However, it is most likely to be able to assemble such a frame with your own hands. When installing rafter systems of such roofs, the Mauerlat is also previously laid on the walls of the house. In this case, it is best to mount it closer to the inner edge of the walls. Floor beams in such a roof are usually carried outside the box in accordance with the angle of the rafters.
Further work is carried out in the following order:
extreme end racks are mounted (two on each side);
intermediate racks are installed along the reference cord;
racks are connected by girders (from the side of the long walls of the building);
puffs are mounted between paired racks;
installed layered (lower) rafters with fastening to racks and removal of beams;
for puffs that simultaneously perform the function of beams of the attic ceiling, racks are mounted under the ridge using a landmark cord;
the ridge board itself is installed;
hanging rafters are mounted.
Using this technology, the end result is a durable rafter system of a mansard gable roof. Sheathe it in the future can be any roofing material.
Rafters when assembling a sloping gable roof are fixed to the supporting elements, usually using steel plates. In roofs of this type, lap feet are often further strengthened using struts. The bottom edge of these elements are fixed to the racks. In this case, the rafter system of the gable roof attic is obtained as reliable as possible. Braces are usually used when installing large-sized roof frames.
Crate Stuffing
The rafter system of the gable roof is quite simple. One of its essential elements is, of course, the crate. The installation technology of this element of the roof depends primarily on how the subsequent owners of the house want to see the attic - cold or residential. In the first case, the crate is stuffed on the rafters immediately after their installation. If the attic or attic is supposed to be made residential, the waterproofing and insulation are first installed.
In this case, the work is performed in the following order:
between the rafters from the side of the future attic a rare "mesh" of wire is attached to create support for the insulation;
between the rafters, mineral wool slabs are laid by surprise;
on top of an insulator mounted on 3 cm thick bars, a plastic film is mounted with a slight sag (not more than 2 cm);
the crate itself is stuffed onto the bars.
The crate can be mounted on the rafters with different steps. The choice of this parameter depends on the type of roofing material used for roof sheathing. For example, when using a metal tile, the step between the battens will depend on the distance between the waves of the sheets.
In any case, the boards should be fastened under the casing, of course, at the same distance from each other. At the top of the slopes, near the ridge, two rows of crates are usually laid back to back. The boards are also mounted on the lower edge of the rafters.
Solid crate
On gable roofs, in most cases, it is a rarefied crate that is mounted. But sometimes it is necessary to do it when assembling such roofs. This is done, for example, if they want to cover the roof with roofing material or flexible tiles. The basic scheme of the device of the rafter system of the gable roof in this case will be the same. But instead of a board on such roofs, some sheet material is used to assemble the battens. Most often in our time, an inexpensive OSB is used for this purpose.
In some cases, such sheets are attached directly to the rafters or to the bars holding the waterproofing. .
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The scheme of the rafter system of a gable roof with an attic is more complicated. Roofs of this type are usually more expensive. But at the same time, it is easy to equip a fairly spacious and comfortable living room under such roofs. In this case, the roof slopes from the inside are first fitted with a vapor barrier. The use of such material for attics is mandatory. The air inside the house is in most cases warmer than outside. Because of this, large amounts of condensation can accumulate in the attic structures of a residential building. Without a vapor barrier film, mineral wool will quickly get wet and stop fulfilling its functions.
At the final stage, when arranging the attic, the ramps are sheathed, for example, OSB. Then they simply get off with some kind of finishing material - they are pasted over with wallpaper, they are trimmed with lining, decorative plywood, drywall, etc.