The device of the truss system of a gable roof of a wooden house. Types and arrangement of a gable roof

Housing construction today is so diverse that sometimes the structures being built take on a completely bizarre fantastic look. In particular, architects like to experiment with a roof that is made transparent, and in the form of tree foliage or a flower, and a skateboard area - in general, their imagination is completely limitless. But we are somehow closer to simpler options, for example, a gable roof. We will talk about what it is and what the gable roof truss system consists of in this article.

It is this type of construction that is most popular in the construction of residential buildings, since with its help a sufficient attic space is created that does not require additional insulation. In addition, a gable roof is not as difficult to install as, for example, a four-slope one, and also does not require huge investments for its installation.

A gable roof is a structure consisting of two rectangular planes connected in the upper part with each other, and in the lower parts with the walls of the house. The end part of such a building is usually built from the same materials as the walls of the building, sometimes the entrance to the attic is also built here.

Recently, it has become very popular to build an additional room in the attic space, often used as a summer guest room. The installation of a gable roof truss system and the subsequent insulation of the resulting room allow you to create a full-fledged room in which you can live both in summer and in winter.

All the advantages of gable structures

The main components of a rafter roof are the Mauerlat and rafter legs, in addition, various struts, racks, crossbars, stops and battens help to make the structure durable and reliable. The gable roof drawing also includes a layer of insulation, vapor barrier, waterproofing and the roof itself. Thanks to all these elements, a gable roof has several advantages:

• simplicity of technical execution;
• low probability of leaks, as the design is one-piece;
• high profitability, because a relatively small amount of materials is spent on its construction;
• the possibility of arranging a full-fledged residential area in the attic;
• ease of repair in case of defects;
• high strength and wear resistance.

The angle of inclination is an important component of a solid roof

The value of the angle of inclination is determined depending on the weather conditions of the region of residence, on the characteristics of building materials and on architectural requirements.

For example, in areas where heavy rainfall is normal, the roof is always made at a high angle. This is necessary so that snow masses accumulate on its surface as little as possible, which can lead to the collapse of the building. In regions with the strongest winds, sloping roofs are most often built, since the wind pressure on such structures is significantly reduced.

In whatever climate zone the dwelling is located, the gable roof truss system cannot be built at an angle of less than 5 degrees!

Recommendations for calculating the area of ​​\u200b\u200ba gable roof

Roof area calculation - picture

Calculating is not as difficult as it might seem at first glance, but this painstaking process requires perseverance - all data must be double-checked at least three times. Agree, no one wants to spend money on building materials that are completely unnecessary to him.

In some cases, the measurement of the roof area can be complicated by some "obstacles", for example, the presence of an attic or an unusual shape of the roof - here it is unlikely that it will be possible to do without the help of a specialist. We will consider the calculation of the area on the classic version of the roof with two slopes:

• First, we determine the length of each slope, it is equal to the distance between the lower edge of the ridge and the extreme point of the eaves;
• We take into account all elements of the roof: parapets, overhangs, firewall walls and other structures that create additional volume;
• We determine the type of roofing material for which we will calculate the area;

It should be borne in mind that in the case when the roof is covered with a rolled or tiled type of material, the length of each slope will become less by about 0.7 m.

• Elements such as ventilation shafts, windows and chimneys are not taken into account;
• When, taking into account all the details, the area of ​​\u200b\u200beach slope is calculated, we calculate the slopes: we multiply the elements of the slopes by the cosine of the angle of inclination of the roof, and we calculate the area only by overhangs.

For the greatest convenience of calculation and obtaining correct data, it is best to calculate the area of ​​\u200b\u200beach element separately, and then add the resulting numbers.

The roof area has been calculated, the roof has been decided - it remains only to understand in detail all the structural elements, such as rafters, Mauerlat, side / ridge runs, struts and braces, as well as diagonal connections, after which you can proceed to the calculation of a specific type of truss system.

Hanging and layered rafters

Of course, such a structure as a do-it-yourself gable roof truss system in the minds of many seems to be something very complex and time-consuming. But if you carefully consider the construction of such a structure and study the necessary material in advance, the question will remain only in the “number of hands” that you will need for the construction process.

Let's start with such a component of the roof as hanging rafters. These bars have only two points of support - the walls, so the main loads acting on them are bending and compression. The weight of the roof, as well as the action of snow and wind, is transferred to the walls through the hanging rafters so that this pressure is compensated, the rafters are connected with a puff made of metal or wood. You can place it at any height, but the higher it is, the stronger and stronger it should be.

Laminated rafters are bars that have an intermediate support resting on the inner wall of the house. The main effect on such a structure is bending. The supporting structure of the roof is made only of layered supports, when the distance between them is not more than 6.5 m.

The same roof can consist of layered and hanging rafters at the same time: where there is an intermediate support, layered rafters are erected, and where not, hanging ones.

Mauerlat and runs

The lower part of the rafters in houses built of timber rests on the upper crown, and in buildings made of brick or foam concrete, on a special timber called Mauerlat. For its installation, a waterproofing material is placed on the inside of the load-bearing wall, on which the Mauerlat lies. The length of the beam can be equal to the length of the wall of the building, or it can be adjusted to the size of each rafter leg - this is even more economical.

Ridge run - a bar to which the upper parts of the rafters are fixed. That is, it is the ridge of the roof. Its length depends on the length of the roof, so both a solid array and several logs are used for its construction.

Side runs are needed for additional support of the rafters, their emphasis is also placed on the gables of the building. The ends of such purlins are sometimes released outside the gables, thus, unloading consoles are obtained, as a result, the pressure of the roof on the central part of the purlin is significantly reduced.

If the roof of a building is built from heavy materials, such as natural tiles, then the side girders are made in the form of a rocker, for this the logs are slightly hemmed and bent.

A little more about the important elements of the roof

Diagonal overlap - picture

Additional diagonal ceilings are called braces, with the help of which the gable roof truss system is strengthened, and the gables' wind resistance characteristics are increased. The upper part of the braces rests against the gables, and the lower part rests against the central ceiling.

Struts are necessary to reduce the load on the rafter legs, their installation at an angle of 45 degrees and above can significantly reduce wind loads and snow mass pressure on the roof, therefore, in the northern regions of the country, such roof elements are simply irreplaceable.

If the roof consists of slopes of different areas, then their angle of inclination will not be equal. Therefore, for the greatest strength of such a structure, vertical racks are erected at the “fracture” points, on which the side runs are supported. Most often, such structures are built for attic rooms.

In areas characterized by constant strong winds, truss systems are necessarily reinforced with diagonal ties, which are boards with a thickness of 25 to 50 mm. The lower edge of the board is fixed to the heel of the rafter leg, and the upper edge to the middle of the opposite rafters.

Correct calculation of materials for the gable roof truss system

Do not be afraid to independently make all the necessary calculations, because the dimensions of a gable roof, especially if it has the shape of an isosceles triangle, anyone can calculate without deep mathematical knowledge.

So, let's consider the calculation of the gable roof truss system using a specific example. The house for which it is required to build a similar structure has a width (W ir) of 4 m, a length of 6 m, and the angle of inclination of the rafters (Y) should be 120 degrees. The roof will be built of metal tiles, the distance between the rafters is planned to be 1 meter.

First, we find the height of the central support (C):

C \u003d 0.5? W ir / tgY / 2 \u003d 0.5? 4 / 1.73 \u003d 1.2 m

The length of the rafter leg (Ds) is calculated by the following formula:

Ds \u003d 0.5? W ir / sinY / 2 + 0.5 \u003d 2.8 m

0.5 in this formula is an allowance for the roof visor, it must be taken into account without fail!

Roof area (Pk) \u003d D? Ds? 2 \u003d 33.6 m 2

It turns out that exactly this number of sheets of metal tiles you will need for the roof.

The distance between each lath of the crate (Rp) is conditionally taken as 35 cm, which means:

Lathing length = Ds / Rp? D? 2 \u003d 96 linear meters

With a house length of 6m and a distance between the rafters of 1m, we need 7 rafter legs, which means that the amount of timber for them and for the Mauerlat is no less than:

Beam length \u003d (2? Ds + W ir + C) \u003d 75.5 p.m.

The required amount of other materials is calculated in the same way. When all the calculations have been made and the required amount of building materials has been purchased, we proceed to the direct construction of a gable roof.

We build a gable roof with our own hands

So, now we have come close to such a moment as installing a gable roof truss system. This process begins with the construction of beam ceilings.

There are only two mounting options:

• If the attic space is not planned to be used as housing, then boards of size 50? 150 mm.
• To equip the attic, you will already need a beam with dimensions of 150? 150 mm, and each of them fits exactly on the load-bearing walls of the building. This is the only way to create a truly reliable and durable attic structure, only the cost of its construction will be an order of magnitude more expensive than the construction of an ordinary attic. But the living area of ​​the house will increase significantly - decide what is more important for you and think through everything to the smallest detail.

Floor beams are laid across the entire width of the building, leaving 500-600 mm per ledge from the bearing walls - this will protect the wall from water flowing from the roof slopes. Along the entire perimeter of the house, a board is laid on the beams, which will become the basis for the racks of the walls of the second floor - the attic.

For the construction of all roof elements, the following fastening materials are used:

• screws,
• nails,
• self-tapping screws,
• dowel,
• wire,
• metal corners.

Once the racks are installed, you can start arranging the rafters.

Such a do-it-yourself gable roof truss system is the simplest in technical execution. Why? Firstly, because it is not necessary to calculate the device of the rafters depending on the material and location of the insulation.

And secondly, we don’t need the dimensions of the section either.

The easiest way is to "tame" a gable roof of a regular triangular shape, because all its components will have identical dimensions.

In addition, this system has several other undeniable advantages:

• the cross section of rafters and beams has a high margin for bearing capacity;
• this form is very reliable, since the load on the structure is distributed evenly, and the risk of deformation of the rafter legs disappears;
• the triangular truss system is an independent structure, therefore, in case of malfunctions in other elements of the building, it remains intact;
• the beam, laid with a small protrusion, also serves as a frame for the entire weight of the roof - and this is an additional reliability of the entire building as a whole.

Attic truss system

It will only be about a single-level attic, since it is quite possible to build it with your own hands. It is recommended to entrust the construction of more complex structures to experienced specialists, since it is easy to make mistakes in the calculations without their help, and the result will be disastrous.

A board is placed on the beam, from which the lower part is sawn off - this is done so that there are no gaps between the beams and the rafters.

On the board (100 mm) you need to lay a beam, draw a line at the place of their joining. Then, along this line, the board must be sawn, as a result of which a beveled board should be obtained, which will fit snugly against all floor beams.

Again, we cut along this line, and so on. Performing these steps will ensure that the upper part of the truss system is firmly and accurately fixed, which can be installed. Using the overlay, fasten each row of rafters at the top (on the ridge), and finally fasten the resulting strapping with a special crossbar, which will act as an overlap for the ceiling.

The rigidity of the constructed structure directly depends on how firmly the rafters are fixed to each other. It is best to use special metal lining - so you can achieve the greatest strength of the roof.

When all rows of rafters are fixed, you can begin to check the correctness of creating gables - they must be located strictly at right angles. Here a construction plumb line is useful - an indispensable thing for such situations.

When the correctness of the design is not in doubt, you can begin to fix all the parts together, this will help soft wire, nails or staples.

Now you need to stretch the twine along the top of the gables, so it will be more convenient to install the middle rafters at the same level.

To exclude the possibility of sagging of the rafter system, it is necessary to strengthen the middle rafters with special struts.

The installation of struts usually does not cause any difficulties: their lower part is fixed to the attic rack, and the upper part to the middle of the rafter leg, where you need to cut a groove of the required depth. To fix the structure, you need to choose nails from 200 mm.

That's all - do-it-yourself gable roof truss system is ready! It remains only to build a crate and cover the roof with a roof, but these are completely different technologies, which will be discussed in the next article.

The frame format stands out among a number of types of roofing. It can be done in quite different ways, but in any case, you will need to calculate the rafters and install them according to all the rules. With proper knowledge of the problem, you can solve it on your own without resorting to specialists.

Features and forms of the roof

The frame roof can only be installed with spans no longer than 1220 cm, while the gap from one truss to another is a maximum of 0.6 m. The dimensions of the frame fragments are determined by the span distances and the calculated snow load. Rafters can be either freely installed or accepting loads from attic elements. In the case of a broken roof, it is possible to provide a ceiling height sufficient for a residential attic, and it will look best on a square building.

The multi-gable roof is considered the most complex and hardly accessible variation for amateur builders. A balanced truss system effectively withstands even very high loads, while having an excellent "appearance". Since the slope is steep, the risk of snow retention will be minimal. But at the same time, all structural elements will have to be calculated very carefully, and a lot of waste will appear in the process. In addition, the valley will have to survive exposure to a significant amount of snow.

Purpose and types of systems

Mauerlat can be used in a variety of rafter systems. The mass of the roof of the house varies depending on the area occupied by the slopes and the materials used. But in any case, the load created is very solid. When there is a ridge on the structures, a truss frame must be provided, with legs resting against the walls. Force is applied along several vectors at once, and in the cold season, the accumulation of snow only exacerbates the problem.

Mauerlat is designed to eliminate this shortcoming and prevent the destruction of the walls. This word means a beam of significant section, which can be both wooden and steel. In most cases, they take the same material that was used to form the rafters, but be sure to achieve continuity of the strapping or create strong and especially stable joints. The use of Mauerlat is abandoned only in log houses or in buildings built using frame technology - and even there they have their own parts that perform a similar task. When it is not possible to make a non-breaking block, all fragments must be exactly the same length.

A T-shaped roof is characterized by a tie-in of two wings at a certain angle. Because of this, it is necessary to form a valley. The outer rafters will rest against the support boards. In addition to them, there will also be basic parts that are directly fixed to the wall. In order for everything in the valley to correspond to the task being solved, wooden elements 3.8 cm thick are used. The crate is supposed to be made monolithic, the coating is attached to it with clamps every 50 cm. steel, you can slightly reduce this figure.

A reinforcing belt is often equipped under the Mauerlat. This is especially important if you plan to insulate the roof and provide reliable waterproofing. Such a belt is formed from the same mixture that is used to build the foundation. Completely the entire formwork is poured with concrete in one step, the slightest individual layers are unacceptable. In the aerated concrete wall, intermediate jumpers are cut down at the top line of blocks - and a practical gutter immediately appears. The Mauerlat is attached either with a tie wire, or with reinforcing bolts (but they will not help in any way without a reinforcing belt), or with building studs.

Having dealt with the support for the rafters, you need to find out what they can be, and what is more correct to use to support the roof. Hanging rafters are used if there is no main wall inside the building, their support points are located exclusively on the outer contours.

Such supports were in demand during the construction of:

• residential buildings with one span;
• production facilities;
• various pavilions;
• attic.

This option should not be underestimated, thanks to engineering developments, suspended rafters are able not to bend, covering spans of 15–17 m. But it is important to understand that they gain all their capabilities only in close interaction with other details. You will have to use puffs, and grandmas, and crossbars. The simplest truss is made of two beams connected in the upper position; in configuration, such a device is close to a triangle. The horizontal connection of the frame parts is provided by a tightening (a beam made of wood or a metal profile).

Due to the tightening, the transfer of thrust to the walls is excluded, while the force applied in the horizontal plane is suppressed. The outer walls experience the action of only those forces whose vector is oriented vertically. Builders do not always place a puff at the very bottom, often it is set at the very ridge. In preparation for the construction of the attic, this element is most often placed higher than the base of the rafter legs. Then it will be possible to make a floor, on the ceiling of which you will not have to beat your head with any careless movement.

Hanging rafters for spans longer than 6 m must be reinforced with hangers and braces. In this case, the monolithic puff is replaced by one assembled from a pair of connected beams. In the classical scheme (triangular hinged), the grassroots bases abut against horizontal parts. For the normal functioning of the system, it is required that the height of the ridge is at least 15% of the span of the trusses. The rafters act on the bend, but tightening does not allow them to move to the sides. In order for the beams to bend less, the ridge knots are cut in with the expectation of eccentricity (the occurrence of a bending force opposite in vector).

Mansard attics are built for the most part with the help of triangular arches on three hinges, and the puffs are assigned the function of floor beams. The components of the tightening are bolted by means of an oblique or direct cut. Raised tightening can also be used in the construction of rafters under the attic. The higher it rises, the more the ceiling can be raised. But it is important to remember that at the same time, the loads on all elements also increase. The transfer of forces is carried out on the Mauerlat with the help of a movable mount, which dampens dimensional changes due to changes in humidity and temperature.

The rafters can be subjected to uneven loading, since it is higher on one side. This leads to a shift in the same direction of the entire system. You can eliminate such an unpleasant effect if you take out the rafters beyond the contour of the walls. The tightening with such a decision ceases to be a support, it transfers either tensile effects (if an attic is being arranged), or stretched-bending ones (when an attic is being built). Hinged arches with the inclusion of a crossbar differ from the previous version by replacing the sliding support with an identical one in function - rigid. Due to the change in the type of supports, the type of stresses generated also becomes different, the rafter system turns into a spacer.

The puff is formed in the upper lobe of the arch. Its purpose is to endure no longer a stretch, but a compressive effect. Additional tightening, reinforcing the crossbar, is needed with a significant load. Arches with suspensions and struts complement the arch systems with headstocks. Such a system is needed for significant spans (from 6 to 14 m). The struts that correct the resulting bend must rest against the headstock. Regardless of the specific type of truss system, it is necessary to carry out all the details and their connections with each other as clearly as possible.

Not always hinged rafters can perform the task. Then the slanting elements come to the rescue. This type of rafters is used under hip roofs and under roofs equipped with a valley. Their length is longer than in the usual case. In addition, they become supports for the shortened rafters of the slopes. That is why the load on the rafters is about 50% more than in other designs.

Thanks to the increased length, it is possible to:

• resist significant impacts;
• form beams without cuts;
• bring the parts to a single size by pairing the boards.

To build a hip roof with many spans, the diagonal legs are provided with supports. Such supports are made in the form of standard struts or racks of timber, or a pair of connected boards. Support through a lining made of wood and a waterproofing layer is made directly on the reinforced concrete floor. The struts are placed at an angle of not less than 45 and not more than 53 degrees, at the bottom such a detail rests on the beds. The angle of installation is less important than the ability to fix parts of the rafters at the point experiencing the strongest load.

Sloping rafters placed in openings up to 750 cm should be held by struts only in the upper lobe. With a length of 750 to 900 cm, a truss truss or rack is additionally mounted below. And if the total span length exceeds 9 m, then for maximum reliability in the middle you need to put a rack, no other support will do. If the selected floor is unable to withstand the load, it will have to be reinforced with a beam. The type of support in the ridge is determined by how many intermediate supports are used, what they are, how the key layered rafters are made.

In addition to the type of rafters, you need to clearly understand their material. Both wooden and metal structures can be good, but only each in its place. Even the high strength of the metal does not allow to push the usual wood. The tree has proven its benefits for thousands of years, and now it is even gaining popularity due to its excellent ecological characteristics. Boards and timber can be bought at an affordable price, and if something has not been taken into account, it is always easy to saw off the desired fragment or build up a part right on the construction site.

Sometimes there are problems associated with the operation of the created structures. Wooden rafters will have to be carefully treated with antiseptics, as well as means that block the development of mold colonies and insects. The combustibility of wood is suppressed due to regular processing, and in addition, it is too difficult to find the necessary components for slopes longer than 7 m. Before installation, the walls are laid with a mauerlat, made from a log frame or based on a block of timber. The thickness of the structures is at least 180 mm, this is the only condition for a uniform distribution of loads.

Metal rafters are inevitably heavier than wood rafters for the same section. Therefore, the walls need to be strengthened, the work on their construction becomes more expensive and longer. It will not be possible to mount metal blocks manually; cranes will be required. It is impossible or very difficult to adjust the dimensions, the geometry of the rafters, so you will immediately have to build the walls as accurately as possible and eliminate errors during their construction. The slightest mistake can make an expensive block almost useless in practice.

Metal rafters are connected by welding, and welded joints are inevitably weakened, as corrosion develops rapidly there. The cost of the work is very high, and when performing them, it is necessary to comply with the requirements of fire and electrical safety. But there is such an indisputable advantage as the ability to support a roof slope from 700 cm and longer. If you use a special anti-corrosion paint, the durability of metal structures is fully guaranteed. All these advantages allow you to quickly and comfortably build industrial buildings with a significant height and length of spans.

How to choose: what to consider?

The truss system should be chosen as correctly and clearly as possible.

When looking for a suitable solution, you need to pay attention to the following points:

• strength;
• the ability to support the slopes and the roof as a whole of a certain size and geometry;
• creating a positive aesthetic image of the building as a whole.

Technical parameters take precedence. Even the most beautiful structures that follow the principles of design will not show their positive qualities if they last too little. Experienced builders always analyze the average annual and seasonal temperatures, the financial capabilities of developers, the maximum possible wind speed and the severity of the overlying roof. The future use of the under-roof space and the scale required for it are also taken into account. Wind, snow and rain should not be underestimated, since these factors can have a very strong effect on the roof, and through it on the rafters.

If it is reliably known that a particular area is characterized by heavy snowfalls, the minimum slope angle is impractical. This point is even more relevant when using flat roofs. Under the pressure of accumulating precipitation, the frame can rapidly deform or water will pour inside. Another thing is when a certain region is often subject to the arrival of cyclones and the strong winds they bring. Here the slope should already be made smaller, then the situation with the disruption of individual structural elements will be practically excluded.

Mistakes can be avoided if you look at houses already built nearby and operated for a long time. By accurately reproducing their roof structure and the rafter system interconnected with it, one can best take into account local specifics. But not everyone follows this path, sometimes the task is to develop an exclusively original project. Then you will have to carefully collect the initial data, carry out scrupulous calculations. In the absence of special knowledge, it is better to attract qualified performers to help.

After analyzing the total load created by wind and snow, it can sometimes be found that certain parts of the truss complex need selective reinforcement. When assessing the required angle of inclination of the roof, attention is also paid to the type of coating used. A heavy metal tile or corrugated board with a very large slope can spontaneously slide down, you have to additionally fix them, complicating your work and increasing the cost of installation. In addition, certain materials have a tendency to retain water or become soaked with it, which can only be combated by making the slope steeper. Creating a good roof and truss system that meets such conflicting requirements is not always accessible to non-specialists.

What does it consist of?

The structure of the truss system, as you can see, is quite complex and even contradictory. Each part of this design has a strictly defined role. So, Mauerlat is a long bars of coniferous wood, and strictly resinous wood is used for work. Such elements are laid out along the external load-bearing walls, attached to the base with anchors or rods of a special design (threaded). This part transfers the load from the roof to the wall.

Next comes such a device as a rafter leg. Under this name appears a wooden beam used to build the contour of the slopes. The shape of the structure is always triangular, because it is the best way to help the roof withstand the destructive effects of winds, snow and other atmospheric processes. Rafter legs are placed at uniform distances along the entire roof, the step cannot exceed 120 cm.

The bed is also of some importance for supporting the roof - this is a wooden block that replaces the Mauerlat in some cases. Beds are placed on the internal supporting walls. They turn into the basis of the roofing triangle. Thanks to them, the slopes do not crawl under their own weight. And it is also worth mentioning about the racks - these are bars with a square section placed vertically. They perceive the pressure exerted downward by the ridge assembly and transmit it mechanically to the inner bearing plane. Sometimes the racks are under the rafters.

Struts are designed to strengthen the entire structure of the roof, they connect the legs and beds into one whole. This detail is shaped like a rhombus. The community formed by the puff and struts is called the farm. In addition to them, you also need a crate, which is thin boards stuffed at right angles to the legs of the rafters. It helps to keep the rafter legs as a single system. Absolutely any roof covering is attached to the crate.

Under soft materials, the crate should be made inseparable, and plywood is considered the best tool. At the very top is a ridge, which logically and physically completes the roofing triangle. The connection of a pair of opposing legs of the rafters is provided by a square piece of wood which prevents the entire roof from collapsing. And at the very bottom of the pitched roof there is an overhang, which extends approximately 0.5 m from the perimeter. Thanks to him, the streams of rain leaving the roof do not flood the outer bearing planes and do not harm them.

Fillies are used only in the situation when the rafter legs cannot be made along the length that would allow organizing the overhang. Connecting with boards of reduced section effectively solves this problem. For fastening the wooden elements of the rafters, it is most often recommended to use clamps, staples. It is undesirable to use nails, because the tree pierced by them becomes weak and fragile after a few years. Therefore, if professionals use connections made directly on the construction site, they use bolts.

But even a bolted connection weakens building structures, albeit relatively slightly. The strongest are the connections with the help of clamps or staples made of metal. Only their industrial production can maximize the quality of products, since deviations from the norms and deterioration in quality are excluded only under strictly standardized and fully controlled conditions. You can assemble a truss structure from completely finished trusses very quickly, there is no risk in using it. Another thing is that it is required to collect information about the necessary characteristics as accurately as possible and transfer it to the manufacturer without distortion.

In addition to these elements, the truss system borders on the valley. This is the name given to a special connection of a geometrically complex roof at points where its trajectory changes. The difference from the ridge is that in such places the roofing parts form a negative angle. The technical essence of the product lies in the fact that the gutter helps to divert liquid to the side. The more complex the configuration, the greater the number of such gutters should be.

The cornice beam serves to abut a strut against it, the other end of which rests against the frontal board, while the dropper is not deformed and its configuration is not distorted. Wind connections are those elements of the truss system that transfer the load created by the wind from the roof to the foundation. They not only increase the overall stability of the structure, but also help to avoid tipping over in case of instability of individual parts. The roof will retain spatial rigidity even with very strong winds.

Horizontal wind connections are such elements as:

• braces;
• parabolic puffs;
• complexes of conventional puffs;
• trusses, complemented by a cross-shaped lattice.

Vertically, the preservation of characteristics under strong air pressure is ensured by wind supports and beams. Sometimes a monolithic reinforcing core is used. Engineers have come up with many other options for designing a wind connection. It is provided with frames and semi-frames, pinched props. In small buildings, rigid (resisting compression) or stretched diagonals are used, some covering two spans at once. The location of each of the elements is accurately reflected in the project documentation.

It is not so difficult to understand the qualitative characteristics of truss systems and their composition, if you show care and diligence. But it is equally important to calculate the quantitative parameters of these systems. If you do not do this or make the calculations incorrectly, you can either spend too much money, or encounter leaks, even with the destruction of individual elements.

• roof bends;
• average annual snow mass;
• unevenness in its distribution along the slopes, depending on the steepness of the slope and the wind rose;
• wind transfer of already fallen snow;

• descent of snow and ice masses, runoff of liquid water down;
• aerodynamic characteristics and windage of the structure;
• differences in the strength of the impact on individual points.

It is not so easy to calculate everything necessary, moreover, by simulating realistic situations and including a reasonable margin of safety in the project. Moreover, it is necessary to pay attention to the addition of various loads, to their cumulative effect. But still, any customer is quite capable of evaluating the quality of the work of designers. The loads applied to the truss systems are divided into three key groups: main, additional and extreme.

The main category includes:

• stable factors - the severity of the roof and roof structures, additional elements installed on top of them;
• long-term effects - snow, temperature;
• periodically changing factors - full calculations of snow and temperature effects, taking into account all the subtleties.

An additional group is the pressure exerted by the wind, builders and repairmen, ice and rain. The extreme category includes all natural and man-made emergencies that may occur in a particular place. Their level is predicted with a margin to ensure the exclusion of unpleasant consequences. When calculating the frame roof and the structures under it, the ultimate load is taken into account, if applied, the entire structure crumbles. Additionally, an indicator or a group of indicators is given, upon reaching which various deformations inevitably appear.

The snow drift coefficient reflects how much more snow will be deposited on the lee side and in front of objects (parts) that block the air flow. In problem areas, you will have to bring the rafters as close as possible and thoroughly calculate the required thickness of the front material. The most accurate assessment of all parameters can only be given by multiplying any received figures by the reliability factors. As for the wind, the force developed by it is aimed at dropping steep roofs and lifting from the leeward section of a flat roof. We must not forget that the air flow acts simultaneously on the facades and on the roof slopes.

When hitting the facade, the air breaks up into two waves: one goes down and is no longer of interest, and the other tangentially presses on the roof overhang, trying to raise it. The action on the slope occurs at a right angle, this area is pressed inward. At the same time, a vortex is formed, which tangentially affects the windward sector of the ramp. This vortex bypasses the ridge and begins to create lift already applied to the leeward segment. For your information: when calculating the mass of the roof, you need to take into account the severity of the rafters, insulation, waterproofing and vapor barrier.

The standard load per 1 square meter of the roof is up to 50 kg, regardless of its size and other significant circumstances. By changing the distance from one rafter leg to another, you can set the actual distribution of loads on them. According to most experts, indicators from 60 to 120 cm will be acceptable values. But on an insulated roof, it is worth choosing distances that are equal to one sheet or roll of insulation materials. At the same time, it should be borne in mind that among several suitable options for arranging rafters, the one that gives the best effect with the minimum consumption of materials used is preferable.

When calculating the loads carried by the rafters, they always look at the fact that they do not exceed the ultimate endurance of the roofing material. After all, there is no point in such an excess. If, under the planned impact, the roof will still begin to sag, it is impossible to talk about a solid result. In calculations, the payload from structures connected to truss trusses is calculated according to the contact area that is plotted on the drawing. Such structures include ventilation chambers, attic and ground floor ceilings, and water tanks placed on the roofs. In addition to the amount of pressure on the rafter system, the sharpness of the roof slope is also calculated.

Tilt angle: value

On forums with consultations of specialists and in professional literature, one can find references to three units of measurement of inclination at once. In addition to the usual and expected degrees, there will be percentages and ratios between the sides. Often they get along together even within the same publication or instruction from the manufacturer of roofing materials. But in fact, there is nothing mysterious in this, any consumer can understand the essence. Under the angle of inclination of the roof, experts understand the angle that occurs at the intersection of the horizontal with the roof slope.

In this case, there can be no obtuse angles in principle. Moreover, you can meet a slope steeper than 50 degrees only in decorative elements, all kinds of turrets. The only exceptions to the general rule are the slopes on the lower rows of the rafters of the attic roof. In all other cases, the angles range from 0 to 45 degrees. The relative proportions of the sides are calculated as the ratio between the height of the slope and its projection on the horizontal. This indicator is equal to half the span for a uniformly constructed roof with a pair of slopes.

On a shed roof, the proportion is equal to one, but in more complex configurations, you still have to carry out all the calculations and estimates yourself, without starting from ready-made values. The slope angle is usually expressed as a fraction, with the numerator and denominator separated by a colon. But when the resulting numbers cannot be rounded to whole numbers, it is recommended to use percentages: they simply divide one by the other and increase it a hundred times. Flat roofs are those that have a slope of no more than 5 degrees; a slope of 6–30 degrees is recognized as small, and all other roofs are considered to be steep. The flat design drastically increases the usable area and is quite wind resistant, but it will need to be manually cleared of snow and strengthen the waterproofing to the limit. The slope is necessarily consistent with the specific material, and the required values ​​\u200b\u200bcan be found in the instructions from the manufacturer. In order to calculate even the most complex and bizarre roof configurations, they are mentally divided into triangles and the angle is calculated separately in each.

Step, length and section of rafters

When it became clear how long the slopes are, what angles formed by these slopes with a horizontal plane, it was time to do the actual calculation of the rafters. If the roof frame is made of a 5x15 cm timber under a metal tile, the mounting pitch sways from 0.6 to 0.8 m. As the slope grows, the gap also increases. If the roof slopes at 45 degrees, you need to put rafters every 800 mm, and for slopes of 75 degrees, you can add another 200 mm.

The next important parameter is the length of the rafters. It is closely related to the step: if the blocks are made long, they are brought together as much as possible, and when a single part is shortened, they are moved apart. When calculating the step of the crate, they proceed from the type of tiles laid on top and from the fact that an integer number of rows should be laid out on each slope. If you get a fraction, it is better to round, reduce or increase the indicator a little. The rafter legs under the metal tile, the cross section of which is 15x5 cm, range from 65 to 95 cm. You cannot increase the step when the cross section of the crate is 3x5 cm.

In order for the insulation to be better ventilated, rows of holes with a diameter of 1–1.2 cm are prepared in the region of the upper edge of the rafters. Ordinary rafters under the corrugated board go every 0.6–0.9 m. with significant cross section. The crate under the corrugated board is assembled from boards with dimensions of 3x10 cm, which are placed at intervals of 0.5 m. The interval must be calculated according to the height and thickness of the materials.

With all the revealed shortcomings of slate, it remains widely in demand. Under the slate roof, rafters with a section of 5x10–15 cm are mounted, 60–80 cm apart from each other. Most often, an average distance of 0.7 m is recommended. Pauses between parts of the crate are calculated according to the steepness of the material. On relatively flat areas, the support of 4 pieces of wood justifies itself. If the roof is made steeper, put 3 bars, separated by 63–65 cm.

We must not forget that due to the responsibility of the truss system, it is better to leave a margin of safety than to make an unreasonably weak type of rafters. For their manufacture, timber is used, dried to a maximum of 15%. A non-edged board of the same dryness can serve as a replacement for a beam. Under the ceramic tiles, a 5x5 cm timber crate is used. In the places marked according to the calculated distance, slate nails or simple self-tapping screws are used.

Installation: technology

The construction of the roof involves the use of a standard range of carpentry tools and an electric drill. If metal structures are used, a grinder will be required for precise cutting. Remember that it is impossible to process metal tiles or corrugated board with it, this can damage the material. A hipped roof without racks is made using puffs that reinforce the structure.

In the hip version, it is necessary to strengthen the runs running diagonally. Paired boards and a particularly strong timber are assigned to them. Connection points always have a support (stand), and the main support is placed about a quarter of the length separating the large rafters from the ridge. Under the gables on a gable roof, rafters of a shorter length are always made. But under the main part of the four-slope structure, extremely long parts can be placed, even more than 7 m. To keep them securely, either a rack is used that transfers stress to the ceiling or a sprengel.

The first step in creating rafters under a broken roof is the formation of a support complex in the form of the letter P. It rests on the floor beams and is held by rafter legs. Next, they put three or more runs, two of them are brought to the corners of the frame, and the rest are placed in the middle of the overlap. The final step in raftering is fixing the legs. It is desirable to make truss systems according to a pattern - to connect two boards that are the same length as the rafters, and pin them to each other with a nail. The template is placed with its edges at the points of attachment of the rafter legs and fixed with a cross member.

An additional template (this time plywood) will help to make a mounting saw. Farms are attached to the Mauerlat, starting from the extreme ones. In order not to confuse with the attachment point of the ridge, the tops of these trusses are tied with a straight rope. The massiveness of the puffs increases as you approach the ridge. If the truss elements are bolted, washers or plates should be used. This will keep the nuts from digging into the wood.

How to install the rafters with your own hands, see the video below.

A gable roof is the best DIY option for an inexperienced builder. It is simple in execution, but at the same time reliable and can withstand significant loads from both wind and precipitation. She, of course, is not very beautiful, but in the baths she looks quite organic.

To do everything consciously, it is necessary to understand the structure of a gable roof and the purpose of all its elements. Let's start in order.

Mauerlat

This is a large bar attached to the load-bearing walls around the perimeter of the building. It is this element that accounts for most of the load from the roof. And it is the Mauerlat that transfers it to the load-bearing walls.

For this element, square bars with a size of 100 * 100 mm or 150 * 150 mm are used. They are connected to the walls with embedded studs. If the bath is wooden, then the upper crown usually serves as the Mauerlat. For all other types of walls, a reinforced concrete belt is made into which studs are embedded. Then the beam of the selected section is “put on” on the studs and attracted with nuts. Sometimes it is additionally fixed with long pins.

Since the thickness of the walls is often greater than the width of the mauerlat, it can be laid with bricks from the outside of the timber. This will make the system more reliable. Only wood needs to be wrapped with two layers of roofing material - to protect it from moisture and decay.

Rafter legs and skate

A ridge is a horizontal wooden block located at the top of the roof and connecting two slopes. Rafter legs or rafters rest on it and on the Mauerlat. Since the ridge has a rather large load, it must be made of a considerable section and wood of durable species should be chosen.

The height of the roof ridge is determined based on the slope of the roof and the width of the building. The angle of the roof slope is a value that depends on climatic factors: if there is a lot of snow in winter, then you need to make the slopes steeper. They will snow well. If there are strong winds in the region, the high roof will experience heavy loads and may be damaged.

For medium conditions, the optimal roof slope angle is about 35°-45°. They will not be heavily loaded by the wind, and the snow will not accumulate much. In addition, with such an angle, you can choose any type of roofing: any of the tiles, soft roofing, slate, metal tiles.

Also remember, the higher the ridge is raised (the steeper the slopes), the larger the roof area will be. And this will lead to the fact that the cost of purchasing roofing materials and the amount of work will be large.

Knowing the slope angle and the width of your bath, you can calculate the height of the roof ridge. To do this, the width of the building must be divided by two (if the ridge is in the middle, and not shifted to one side or the other) and multiplied by the slope angle tangent (the first formula in the figure). In order not to look for the necessary coefficient in mathematical tables, it is written out and summarized in a simple table.

Roof slope angle	5	10	15	20	25	30	35	40	45	50	55	60
Tg A (skate height calculation)	0,08	0,17	0,26	0,36	0,47	0,59	0,76	0,86	1	1,22	1,45	1,78
Sin A (rafter length calculation)	0,09	0,17	0,26	0,34	0,42	0,5	0,57	0,64	0,71	0,77	0,82	0,87

Multiply half the width of the house by this factor. Get the height of the ridge for your bath. For example, the width of the bath is 4 meters, the angle is 35 °. We consider: 4 m / 2 * 0.76 \u003d 1.52 m - the height of the ridge from the ceiling.

Now about the rafter legs. They are made from pine or spruce bars, or better - larch. Section 50*150 mm or 50*100 mm. The choice of bar thickness depends on:

The length of the rafter leg is also calculated according to the mathematical formula: the height of the ridge is divided by the sine of the angle of inclination (the second formula in the figure). The sines of the tilt angles are also in the table. Find the right value and count. For example, for the ridge we found is 1.52 m and the angle of inclination is 35 °, the rafters will need 1.52 m / 0.57 = 2.67 m.

Roof overhang and filly

But the roof does not end exactly above the load-bearing wall. It extends beyond the walls by about 40 cm. This ledge is called the roof overhang. This is done so that the water flows further from the foundation, does not wash it away. Therefore, the rafter legs are taken longer. If their length is not enough, they are grown with boards, which are called "fillies".

To organize the overhang of the roof, boards are added to the rafters - filly

Types of truss systems

Rafter systems come with hanging or layered rafter legs. The hanging ones rest only on the outer walls of the building (on the Mauerlat or the upper crown). In order to increase the reliability of the system, so as not to ruin the walls, they are connected by puffs (also called a jumper or crossbar). This type of rafter system is suitable for buildings of small width (less than 10 m) and in cases where there is no load-bearing wall running in the middle.

Two types of truss systems - with hanging and layered rafters

The second type of system is with layered rafters. They rest on a ridge beam and a mauerlat, but the load from the roof is also distributed to the middle load-bearing wall, through vertical bars - girders, which are installed with the same pitch as the rafters and rely on the lower puff.

Do-it-yourself installation of gable roof rafters

For most of the baths, the system is made with hanging rafter legs - the dimensions allow this. In this case, less consumption of lumber and less time is required for its arrangement. In this case, most of the work can be transferred to the ground.

They make one triangle from the rafters according to all the rules and sizes. They try it on, and then make the right amount of its exact copies. Finished rafters with puffs and crossbars, fastened and measured, are raised to the roof. There they are set strictly vertically in the designated places and are fixed to the Mauerlat and the ridge.

An example of how to make a gable roof with hanging rafters, see the video.

With a roof slope length of more than 4.5 meters, to increase the reliability of the system, vertical racks are installed, which support the rafter leg at one end, and rest against the floor beam with the other. This is done regardless of the type of installation of rafters: both hanging and layered. They also install slopes that make the structure even more rigid.

In any case, the rafters will need to be attached to the ridge beam, as well as to the Mauerlat. The figure below shows the mounting options for the ridge.

It will also be necessary to attach the rafters to the Mauerlat. How to do this - see the photo below.

Lathing device

Making a gable roof with your own hands ends with the installation of a crate for roofing material. To do this, a waterproofing film or membrane is rolled out on the outside of the rafters. Lay it in a horizontal direction. Starting from the bottom, moving up. The second and all subsequent rows are laid with an overlap of at least 15-20 cm. They are fixed with small nails or staples from a staple gun.

After installing the truss system, a film or waterproofing membrane is fixed on it, and on top - a crate

There are two ways - with or without a counter-crate. The counter-lattice is stuffed along the rafters, and on top there are already lathing bars. Thus, an air gap is formed between the waterproofing and the roofing material. This option is better from the point of view that such a roof will dry out better and faster. And this is very important for baths.

Without a counter-lattice, the bars are packed immediately over the waterproofing. There is also a gap here, but it is smaller, therefore, ventilation will be worse. But this option is also acceptable: less consumption of materials and work, too.

After the manufacture of the crate, it remains only to fix the selected roofing material.

Results

Now you know how to make a gable roof with your own hands. Of all types, this is the simplest option that a non-specialist can make.

The gable roof is very popular, as its construction is considered a relatively simple and quick step in building a house. Different types of gable roofs allow you to choose the appropriate option for a particular building. It will not be difficult to install such a roof structure, even if you have little experience in construction, but, of course, you cannot do it alone. All work is carried out in stages, taking into account the features of such a roof.

Peculiarities

When erecting a gable roof, a truss system and the main details of the roof structure are installed. This includes the frame (in the form of rafters with struts), Mauerlat. They are made from high-quality wood - these are bars 150x150 mm and boards with a section of 50x150 mm. Gable roofs of a symmetrical type with straight slopes (gable roof) are considered traditional. The angle of inclination of the slopes of such a roof reaches 45 degrees, which makes it possible to avoid loads on the structure (for example, during snowfalls and wind).

Other types of gable roofs, for example, with broken slopes, allow you to equip the attic under the roof. In this case, the slopes on top of the roof are more gentle slopes, and below - with a sharp slope. A broken gable roof should be built on a more complex and durable structure. During the construction of an asymmetric roof, the roof ridge is performed with an offset from the center. This is done taking into account the structural features of the building.

Kinds

The frame structure of a gable roof can be:

• layered;
• hanging.

It is characteristic that in most buildings a rafter system of a layered type is used, inside which there are load-bearing walls. The frame thus serves as an intermediate support. With a roof width of not more than 10 m, one support is usually used. A roof with a width of more than 10 m has several proportionally spaced supports. A frame in the form of a hanging type truss system is possible in the case when the building can do with one support, without internal load-bearing walls. Such a roof is built from two belts - the upper one (two rafters), the lower one (rigidly connected puffs). The rafters rest on the Mauerlat, and the ends of the rafters go to the outer walls.

A gable broken roof can be reinforced in the form of support frames that prevent the sloping roof from sagging. So you can get a more durable design. The hanging sloping roof has additional supporting frames, to which the attic walls are installed. The support frame, which is located under the load-bearing wall inside, takes on part of the load, which makes it possible to slightly lighten the roof structure.

Device

The design of a gable roof is characterized by the presence of inclined surfaces on both sides. The area of ​​the base of the roof has a rectangular surface. The slopes do not allow snow and melt water to accumulate on the roof. The roof is naturally cleared. The roof consists of structural units: mauerlat, rafter system, ridge and filly, roof overhangs, struts, puffs, battens and racks. It is worth understanding what is characteristic of all the structural elements of a gable roof.

Mauerlat is necessary for the correct distribution of the load on the load-bearing walls from the rafters. For this purpose, durable wood is usually chosen - timber (it can be oak, larch, pine). The choice of timber according to the section is determined by the type of wood (solid or glued). For example, 100 by 100 mm or 150 by 150 mm. It is worth noting that when choosing a metal truss system, the Mauerlat must also be made of metal.

The main element of the gable roof system is the rafter leg. These elements are made of durable timber and logs. When connecting the rafter leg, a truss is formed from above with a different type of intermediate support. An important role here is played by the parameters of the rafters and structural nodes.

Tightening is necessary to connect the rafter system (rafter leg) and to give strength and the necessary rigidity to the structure.

The run is of two types: ridge run, in which installation is carried out at the junction of the rafters (the roof ridge is further installed at this place), and the side run, which provides the roofing elements (truss) with additional rigidity (the size and number of such runs will depend on the load on the structure ).

Rafter racks in the form of a vertical bar also take on a significant part of the load from the roof. The gable roof rafter post is usually located in the center. If the span is larger than usual, then also on the sides. When erecting an asymmetrical roof, the racks are placed depending on the length of the rafters. For a broken roof, the installation of racks is carried out on the sides, while leaving free space. If two rooms are planned under the roof, then the rafters are placed in the center and on the sides.

Struts are supports for racks. When mowing at an angle of more than 45 degrees, the roof is better protected from deformation (snow, wind). Depending on the climatic zone, both longitudinal and diagonal struts can be installed with a rafter pair on the same plane.

The bed serves as a reliable support for the racks. This is the strut attachment point.

The crate is necessary to fix the materials and structural elements of the roof. The crate is installed perpendicular to the rafter legs. One of the important purposes of the crate is to redistribute the load from the roof to the truss system.

Requirements for building materials

The choice of materials for the truss system is an important step in preparing for the arrangement of the roof structure. When calculating the material for a gable roof, one must proceed from the fact that it must be high-quality wood, the material does not have knots, damage and wormholes, it is well processed and impregnated with special compounds (for safety and reliability during operation). For the reliability of the structure, there must be a stable connection of the elements of the entire truss system. The roof should be a solid construction of modern quality materials.

Wood species such as larch, cedar, spruce or pine are easily processed, so they are most often used in the rafter system. The rafters are made from a beam with a width of 10 to 15 cm and a thickness of 5 cm. In this case, an aged beam is usually used, which will not change shape after the roof is arranged. This is necessary to increase the stability of the structure. In addition to timber, boards are taken for rafters, especially when it comes to raising the roof of a private house.

In multi-storey construction, metal rafters are used. The disadvantage of a metal truss system for private housing construction is that such a design is not able to retain heat. Wood has more advantages in this regard - the material is distinguished by a high degree of thermal insulation and energy saving. Wood is divided into grades. First-class material goes into the creation of hanging rafters and puffs. Racks and struts are made from the material of both the first and second grades.

Projects and drawings

In the process of planning a gable roof, a drawing is prepared. This is a diagram of the future design, where there are slopes, a pediment, a ridge. In fact, the plan is a drawing with detailed elements in different projections, showing how to tie the rafters. Drawing up a drawing of a gable roof is carried out taking into account all stages of work.

The scheme of its construction includes:

• bars for crates;
• beams and rafters;
• scheme of laying heat and waterproofing;
• roofing layout;
• scheme for installing additional fasteners;
• installation drawing of the ventilation system, chimney.

A well-designed roofing plan will reduce the expense item for the purchase of building materials. To create a project of any type, one or another type of material is used, based on calculations and taking into account the reliability of the coating. The size of the roofing is also taken into account. When drawing, a part of the truss system is necessarily prescribed, which allows you to understand how maximum the load on the roof can be.

The plan also includes:

• stormwater plan (storm sewer of a certain length);
• elements of the connection of slopes;
• construction area;
• diagram of the junction of the roof (pressure profile).

The type of roof should be clearly shown in the design scheme. Detailed details on the diagram will allow you to complete the work faster and better.

Charting

Depending on the features of the roof (single or gable, shape, etc.), project documentation is drawn up.

This work takes place in several stages:

• a sketch of the future roof is drawn up (at this stage, the drawing should have a finished view of the roof with a study of the style design of the building);
• the main roofing elements are being worked out (the degree of load and the amount of materials are displayed on the drawing);
• the diagram shows the construction of the roof.

It is worth considering that the differences in pitched structures are associated with the type of rafters.(hanging or layered), with uneven angles of inclination, with the dimensions of the overhang of the eaves. It is also worth considering design errors. One of the most common of them is an error with the calculation of the consumption of materials for the entire complex. The process of drawing up drawing schemes is best entrusted to specialists. The roof structure is being built in accordance with accepted building codes. In addition, it is important to minimize possible errors and defects. So, if the choice of the type of roof and the method of installation are chosen incorrectly, this will cause the collapse of the roof structure. With an incorrectly drawn slope and its construction, there is a risk of increasing the load on the roof. Although mistakes are made in the design of ventilation elements. The drawing itself should not be complicated, but the rules for installing all roofing elements should be followed, respectively, they should be prescribed. A professionally executed roof plan increases the safety of the structure.

Calculation

The importance of calculating the gable roof truss system cannot be underestimated. During the design process, it is necessary to calculate the usable area and, based on the data obtained, decide how high the vertical racks will be. In this case, several factors matter.

When erecting a roof structure, it is important to calculate the maximum load on the roof of the house, on all rafters and ceiling beams. It may be necessary to strengthen the rafters, then adjustments are made to the project. For example, it may be necessary to use additional pads or a beam with a larger section than planned. The weight of the entire truss system is also important. In this case, the calculation is carried out taking into account not only the cross-section of lumber, but also the density and moisture content of the wood, and the step distance between the rafters is determined.

To date, there is a special classification of loads on the roofing system:

1. The main load concerns the weight of the truss structure, load temperature, snow and other weather factors.
2. An additional load concerns the calculations of the influence of wind and ice.
3. Force majeure loads are associated with man-made circumstances (modern roofing must withstand everything).

The limit calculations of the truss system, taking into account all loads, are built according to two criteria (limits or states): the limit at which the destruction of the structure is possible, and the limit at which the probability of deformation and deflection is taken into account.

slope

It is important to correctly calculate the angle of inclination of the slopes. With a standard house width of 6-8 m, the angle of the slopes is 45 degrees, but this is not enough for the space in the attic. With a tilt angle of 60 degrees, the design will cost more, but the entire roof will be more successful. At 45 degrees of inclination, you can choose any roofing materials. If the gable roof is initially planned asymmetrical, then in the attic space you can safely equip a residential attic, but for this you need to calculate the usable area. A standard gable roof is usually chosen. In this case, it is important to take into account the loads on the roof due to wind and snow. With an increase in the angle of inclination of the slopes, the consumption of materials will also increase. But the performance characteristics of such a roof will compare favorably. If you plan to build a gable roof with unequal slope angles, then all work can be done in the original design. However, when designing, it is better to build on the classical design in the form of a symmetrical roof with an isosceles triangle at the base.

Step

The pitch of the rafters used to create the roof is one of the fundamental ones in the construction of the structure. There is a dependence of the pitch of the truss system on the roofing material. As the latter, corrugated board, slate, soft roofing or metal tiles are used.

Roof slate is used everywhere. This roofing material is characterized by relative strength, low cost and resistance to temperature extremes. However, the material has a certain weight, respectively, it is necessary to provide the roof with a powerful truss system. It is worth considering that for a slate roof there must be at least three points of support (in the center and along the edges).

In recent years, metal tiles have become quite widespread among roofing materials. The material is easy to install and has an attractive appearance. Metal sheets for roofing are convenient to use, as they are light in weight. In this regard, the distance between the rafters can be large (for example, 600-950 mm with a sectional beam 150x50 mm).

The corrugated board covering can be made of galvanized steel sheet with a special protective coating (against external weather influences). Modern corrugated board differs in color, corrugation width. Externally, such a coating differs in design. The step between the rafters under the corrugated board will depend on the type of profile, on the angles of inclination and the configuration of the roof. For the rafter system, in this case, a bar with a section of 50-75 mm is used. It can be a board 20-50 mm wide.

Tools

When installing the truss system, a set of tools is required. For this purpose, traditional tools are usually dispensed with - an electric saw (it can be a hacksaw), a hammer and screwdrivers. Sheathing of the roof with metal sheets is carried out with special scissors for metal. It is impossible to cut polymer-coated material with a simple grinder, so as not to damage the top layer with sheet protection. Otherwise, the skin will quickly rust. To cover the roof with roofing material, you need a barrel in which bitumen will melt.

Undoubtedly, when performing installation and any construction work, you cannot do without a reliable ladder. You should also think about your own equipment. For example, during work, shoes with non-slip soles are needed.

Mounting

Do-it-yourself installation of a gable roof truss system is better with assistants, and many structural elements cannot be installed alone. Installation of the truss system is carried out in several stages.

Let's consider them step by step:

• First you need to make a template. Rafter trusses are assembled according to a template. So, you need to take two boards of the same length as the rafter leg. They are attached to each other from the edges with one nail. The result is a "scissors" design.
• This structure must be placed with other edges in those places where there are supports on the rafter legs. The angle obtained in this way (according to the slope of the roof slope) is fixed on several nails. Fastening the corners must be done on an additional crossbar between the boards.

• Next up is another template. With it, you can further assemble the structure. Installation of cuts on the rafters is in progress. The template itself is easier to make from plywood.
• The saw cuts are cut into the rafters using a template. The elements are connected at an angle of inclination of the slope. The finished triangle is the truss truss. It is lifted to the roof and attached to the Mauerlat (this will require logs, stairs).
• The fastening of the rafter system to the Mauerlat is done with the help of nails, staples, corners. And the wooden "shorty pieces" help to secure the structure from displacement along the axis, they need to be placed over the entire area.
• At the initial stage, two gable trusses are installed along the edges. Installation and proper fixation horizontally and vertically is carried out using temporary struts to which the structure is attached.

• For reliability and convenience, a cord is pulled along the edges (between the tops of the trusses). You need to fasten it in such a way as to designate a place for the future skate. You will also need a cord when installing intermediate rafters.
• At the next stage, the remaining roof trusses are lifted and installed (at a certain distance (usually 0.6 m) from each other).
• In the presence of bulky structures, if there is a need to strengthen the structure, they are strengthened with crossbars, struts and supports.
• The run (ridge beam) is placed on special supports. Rafters of various types (short, intermediate or diagonal) are then attached to it.

The basis of the frame is the Mauerlat. Its manufacture and assembly forms the basis of the roof structure.

Mauerlat fasteners

The frame structure of the rafters is fixed to the floor beams. However, in this case, the load on the truss structure is distributed at the points where the beams are attached. This approach when installing a roof structure is possible for small and light buildings. Mauerlat is needed to evenly distribute the load of the roof in the upper part of the walls. Mauerlat is mounted parallel to the ridge of the future roof. This is how the main frame is formed. A wooden bar with a section of 150x150, 100x100 or 100x150 mm is used to manufacture the Mauerlat.

Roof installation is a complex multi-stage process. In order to independently assemble and install the truss system, it is necessary to carefully study the methods of connecting the elements, calculate the length of the rafters and the slope angle, and select the appropriate materials. If you do not have the necessary experience, you should not take on complex designs. The best option for a small residential building is a do-it-yourself gable roof.

A standard roof of this type consists of the following elements:

Mauerlat is a beam laid on top of the walls along the perimeter of the building. It is fixed with threaded steel rods immured into the wall or anchor bolts. The beam must be made of coniferous wood and have a square section of 100x100 mm or 150x150 mm. Mauerlat takes on the load from the rafters and transfers it to the outer walls.

rafter legs- these are long boards with a section of 50x150 mm or 100x150 mm. They are attached to each other at an angle and give the roof a triangular shape. The design of their two rafter legs is called a truss. The number of farms depends on the length of the house and the type of roofing. The minimum distance between them is 60 cm, the maximum is 120 cm. When calculating the pitch of the rafter legs, one should take into account not only the weight of the coating, but also the wind load, as well as the amount of snow in the winter.

It is located at the highest point of the roof and most often represents a longitudinal beam connecting both slopes. From below, the timber is supported by vertical racks, and the ends of the rafters are attached to the sides. Sometimes the ridge consists of two boards, which are nailed to the top of the rafters on both sides and connected at a certain angle.

Racks - vertical bars with a section of 100x100 mm, located inside each farm and serving to transfer the load from the ridge run to the load-bearing walls inside the house.

The struts are made from timber scraps and set at an angle between the uprights and the rafters. The side faces of the truss are strengthened with struts, the bearing capacity of the structure is increased.

Puff - a beam connecting the lower parts of the rafters, the base of the truss triangle. Together with struts, such a beam serves to strengthen the truss, increases its resistance to loads.

Lying is a long bar with a section of 100x100 mm, laid along the central load-bearing wall, on which vertical racks rest. Lying is used when installing layered rafters, when the run between the outer walls is more than 10 m.

The crate is a board or timber stuffed on the rafters. The crate is solid and with gaps, depending on the type of roof. It is always attached perpendicular to the direction of the rafters, most often horizontally.

If there is no more than 10 m between the outer walls and there is no load-bearing wall in the middle, arrange hanging rafter system. With such a system, the upper ends of adjacent rafters are sawn at an angle and connected to each other with nails, excluding the installation of racks and ridge timber. The lower ends of the rafter legs rest on the outer walls. Due to the lack of racks, the attic space can be used to equip the attic. Very often, floor beams perform the function of puffs. To strengthen the structure, it is recommended to install the upper puff at a distance of 50 cm from the ridge.

In the presence of a central supporting wall, the arrangement is more justified layered truss system. A bed is laid on the wall, support posts are attached to it, and a ridge beam is nailed to the posts. This installation method is quite economical and easier to perform. If the ceilings in the interior are designed at different levels, the racks are replaced with a brick wall dividing the attic into two halves.

The installation process of the roof includes several stages: fastening the Mauerlat to the walls, assembling the truss trusses, installing the rafters on the floors, installing the ridge, fastening the batten. All wooden elements before assembly are carefully treated with any antiseptic composition and dried in the air.

For work you will need:

• timber 100x10 mm and 150x150 mm;
• boards 50x150 mm;
• boards 30 mm thick for lathing;
• ruberoid;
• metal studs;
• jigsaw and hacksaw;
• a hammer;
• nails and screws;
• square and building level.

in wooden houses Mauerlat functions are performed by logs of the last row, which greatly simplifies the workflow. To install the rafters, it is enough to cut grooves of the appropriate size on the inside of the logs.

in brick houses or buildings from blocks, the installation of the Mauerlat is as follows:

Mauerlat bars should form a regular rectangle and be in the same horizontal plane. This will facilitate further installation of the roof and provide the structure with the necessary stability. In conclusion, markings are made on the bars for the rafters and grooves are cut along the thickness of the bar.

When choosing a hanging truss system, it is necessary to assemble the trusses on the ground, and then install them above the floors. First you need to draw up a drawing and calculate the length of the rafter legs and the angle of their connection. Typically, the roof slope is 35-40 degrees, but in open, heavily ventilated areas, it is reduced to 15-20 degrees. To find out at what angle to connect the rafters, you should multiply the angle of the roof by 2.

Knowing the length of the run between the outer walls and the angle of connection of the rafters, you can calculate the length of the rafter legs. Most often, it is 4-6 m, taking into account the cornice overhang 50-60 cm wide.

The upper ends of the rafters can be fastened in several ways: overlap, butt and "in the paw", that is, with cut grooves. For fixing use metal pads or bolts. Next, the lower and upper puffs are mounted, and then the finished trusses are lifted up and installed above the ceilings.

The extreme trusses are attached first: with the help of a plumb line, the rafters are set vertically, the length of the overhang is adjusted and attached to the Mauerlat with bolts or steel plates. So that during the installation process the farm does not move, it is strengthened with temporary jibs from a bar. After installing the extreme rafters, the rest are exposed, keeping the same distance between them. When all the trusses are fixed, they take a board with a section of 50x150 mm, the length of which is 20-30 cm longer than the length of the eaves, and nail it along the upper edge of the slope. Do the same on the other side of the roof.

The first option: on the rafter leg, at the place of contact with the Mauerlat, a rectangular groove is cut out 1/3 of the beam width. Stepping back from the top of the box 15 cm, a steel crutch is driven into the wall. The rafter is leveled, the grooves are aligned, then a wire clamp is thrown on top and the beam is pulled close to the wall. The ends of the wire are securely fixed on the crutch. The lower edges of the rafters are carefully cut with a circular saw, leaving an overhang of 50 cm.

The second option: the upper rows of walls are laid out with a stepped brick cornice, and the mauerlat is placed flush with the inner surface of the wall and a groove is cut in it for the rafter. The edge of the rafter leg is cut at the level of the upper corner of the eaves. This method is simpler than the others, but the overhang is too narrow.

The third option: ceiling beams are extended beyond the edge of the outer wall by 40-50 cm, and roof trusses are installed on the beams. The ends of the rafter legs are cut at an angle and rest against the beams, fixing with metal plates and bolts. This method allows you to slightly increase the width of the attic.

The device of layered rafters

1 shows the cutting of the struts of the rafters into a bed laid on intermediate supports, and in Fig. 2 - supporting the rafter leg on the Mauerlat

The procedure for installing a layered truss system:

When the main elements are fixed, the surface of the rafters is treated with flame retardants. Now you can start making the crate.

A beam of 50x50 mm is suitable for the crate, as well as boards with a thickness of 3-4 cm and a width of 12 cm or more. Waterproofing material is usually laid under the crate to protect the truss system from getting wet. The waterproofing film is laid in horizontal stripes from the eaves to the roof ridge. The material spreads with an overlap of 10-15 cm, after which the joints are fastened with adhesive tape. The bottom edges of the film must completely cover the ends of the rafters.

It is necessary to leave a ventilation gap between the boards and the film, so first wooden slats 3-4 cm thick are stuffed onto the film, placing them along the rafters.

The next stage is the sheathing of the truss system with boards; they are stuffed perpendicular to the rails, starting from the roof eaves. The step of the lathing is affected not only by the type of roofing, but also by the angle of inclination of the slopes: the larger the angle, the greater the distance between the boards.

After the installation of the battens is completed, they begin to sheath the gables and overhangs. You can close the gables with boards, plastic panels, clapboard, waterproof plywood or corrugated board - it all depends on financial capabilities and personal preferences. Sheathing is attached to the side of the rafters, nails or self-tapping screws are used as fasteners. Overhangs are also hemmed with various materials - from wood to siding.

Video - Do-it-yourself gable roof