The roof is considered the final element in the construction of the building. A load-bearing structure that takes all external loads and distributes them evenly to the internal supports and walls of the house. According to the shape of the slopes of the roof, there are tent, gable, single-pitched. With the help of slopes, you can create a wide variety of shapes - conical, pyramidal, steeple. For Russian climatic conditions, a gable roof - a truss system - is popular.
What is a gable roof?
The gable roof design is a roof with an inclined surface in relation to the walls, which provides a natural runoff of melt and rainwater.
Pitched structures are very diverse, and the appearance and shape depend on the purpose of the building and its outlines in the plan. Therefore, the design must be a good drainage of rainwater. It has an attic, and can be a mansard type.
Gable roof structures most often installed in one-story buildings, which have two rectangular inclined planes. For the device of pediments, triangular parts of the building are used.
The roof of the building consists of the following main elements:
- rafters;
- crates;
- inclined planes;
- Mauerlat;
- horizontal ribs;
- skate;
- valleys;
- overhangs.
The angle of inclination of a gable roof should be more than 5 degrees, and in some areas it can be 90 degrees. The choice of the angle of inclination of the roof slope mainly depends on the characteristics of the roofing materials, architectural requirements, as well as on the climate conditions in the given region.
For areas that receive a lot of rainfall, the slopes should be steep, and also when the roofing material is installed loosely.
Sloping roofs are arranged in climatic zones with strong winds in order to reduce wind pressure in structures. The cost of the building depends on the correct choice of the desired slope, since covering a steep roof will require more building materials, as well as labor costs, so how to make a gable roof you need wisely.
The angle of the gable roof is determined taking into account the type of building and the purpose of the attic space.
What is the truss system made of?
There are truss systems:
- with hanging rafters;
- with rafters.
Your attention! Hanging rafters rest on the extreme supports, as their rafter legs work on bending and compression. Such a design can create a horizontal expansion force that is transmitted to the walls and can only be reduced with the help of a wooden or metal puff located at the base of the rafters.
In this case, the ceiling serves as a beam, and this option is used for mansard roofs. The higher the puff is located, the more powerful it is and the stronger the fastening with rafters should be.
Laminated rafters are used in structures that have intermediate columnar supports or an average load-bearing wall.
The ends of the rafters rest on the walls of the structure, and the middle part - on the supports and internal walls, and therefore their elements work as beams - for bending. Such a roof is much easier, unlike others.
When installed in a single structure over several spans, it is possible to alternate roof trusses - hanging and layered.
Hanging rafters are installed in those places where there are no intermediate supports, and where they are installed layered, if the distance does not exceed 6.5 meters between the supports.
The width of the rafters can be increased due to the presence of an additional support, which is covered by layered rafters up to 12 meters, and if there are two supports - up to 15 meters.
In houses made of timber, rafter legs rest on the upper crowns, and in order for the fastening to be strong enough, they are fixed with a dowel, bolt, bracket.
To connect all the components, a tooth, metal plates and bolts are used. A cornice overhang, at least 550 mm long, is used as an upper trim to protect against the negative effects of precipitation.
The type of rafters used is directly related to the size of the house, but installation is carried out in compliance with some nuances. First you need to correctly calculate the truss system, the calculation of which should be carried out by an experienced specialist.
With an error in the calculation, the most dangerous situation can happen - the destruction of the entire truss system due to an incorrect section of the rafters.
Sometimes these violations are detected in the violation of the joints of the system, and this often leads to the impossibility of using the roof. The gable roof truss system, especially its calculation, should only be calculated by a professional.
Mauerlat mount, methods
Mauerlat is a bar with a section of 15x15 cm, which serves as a good support for inclined rafters and distributes the roof loads, and also serves as a kind of foundation.
It can be used as a substrate for a rafter leg, and is placed along the entire length of the house, if the section has a small width and may sag over time.
To avoid sagging, a special lattice is used, which consists of struts, racks and a crossbar. For this, boards 25x150 mm or wooden plates are used, which are obtained from a log with a diameter of 130 mm.
Mauerlat is settled on the upper edge of the wall, both along the inner and outer edges - it depends on the design of the walls.
Tip! Do not lay the Mauerlat close to the edge of the outer wall. It is attached to the wall so that the wind cannot rip it off.
Mauerlat is laid on the waterproofing material, starting from the very top of the attic floor to a height of at least 40 cm. Runs are supported evenly, after 3-5 meters, on the racks, cut into the bed by the lower end.
The angle between the rafter leg and the strut is about 90 degrees, and when the rafter leg is long, another support is mounted in the form of a strut, which rests on the beds.
Each link is connected to 2 neighboring ones, and together with the rafters they create a stable structure around the entire perimeter of the roofing system. Mauerlat can be placed under the rafter legs in separate segments.
Types of gable roofs
The most economical is a gable roof with a slope angle of 35-40 degrees.
On such a design, the load is distributed evenly, but the space is not suitable for arranging housing. This shortcoming can be compensated by a broken gable roof, which has a slope of 2 parts: the lower one with a sharp slope and the gentle upper one.
This design has a mansard type and snow melts well from it, and it is also able to withstand a large wind load. The truss system for a country house allows you to equip the attic floor.
You can use the attic as a technical room, and in the future you can equip a full-fledged living space. Therefore, a gable sloping roof allows you to use the attic as a habitable area.
The construction of a gable roof lies in the correctness and accuracy of measurements, and during the installation itself, you need to make sure that the structures are absolutely equal, the depth of the cut at the angles of inclination, dimensions, and everything must be properly joined and screwed.
Therefore, a do-it-yourself gable roof requires the necessary skills and knowledge, and its construction should be entrusted to the masters of their craft.
The gable roof scheme consists of the following positions:
- Mauerlat installation
- Installation and installation of rafters
- For structural rigidity (crossbars, struts, girders, racks) - use additional fastening for greater rigidity inside and between trusses (struts between rafters, skates)
- Lathing installation (with further insulation, waterproofing and vapor barrier)
- Installation of roofing material
How to calculate roof area
When drawing up an estimate for the construction of a house, it is important to correctly calculate the area of \u200b\u200ba gable roof. Sometimes these calculations are complicated by the shape of the roof, the presence of many complex, the shape of the roof and broken elements - for example, attics.
In order to calculate the area, you must perform the following steps:
- do not calculate such elements in the calculation as ventilation openings, chimneys, dormer and roof windows;
- set the length of the roof slope to accuracy, starting from the extreme part of the eaves to the bottom of the ridge;
- elements such as parapets, firewall walls, overhangs should be taken into account;
- it is necessary to take into account for which roofing material calculations are made.
In addition, it should be remembered that the length of the slopes is reduced by 70 cm for roll materials and tiles.
When performing calculations on your own, you should divide the entire roof area into separate elements, and calculate each element separately, and then summarize everything.
According to the basic mathematical formulas, the area of \u200b\u200beach of the elements is calculated.
After calculating each slope, you should find out the slope. To do this, each element is multiplied by the cosine of the roof slope angle. The calculation of the area is made only on the cornice overhangs.
When calculating simple areas (gable roof with a slope of 30 degrees) - it is necessary to multiply the area of \u200b\u200bthe slope by the cosine of the angle. And when the roof is more complex, then you can use special programs, only then you can get an accurate calculation.
To obtain the correct indicators, the main thing is a detailed roof plan, but only specialists can perform an accurate calculation.
The pairing of a gable broken and gable straight roof is determined by the following positions:
- sloping roof ridge beam
- ridge beam straight roof balcony
- straight roof rafters
- balcony door frame
- attic gable
- waterproofing
- whole crate
- roof.
This constructive technique is used to increase the space for the roof, which is rationally used for economic and domestic needs or as housing.
The load-bearing part of the roof is made up of a combination of hanging and layered rafters, and also takes on the main loads and transfers directly to the frame of the building.
The main element of the bearing part is the rafter legs, which form with other elements of the farm. In the construction of the frame, the rafters are laid along the slope, while they are supported by their lower finishes on the floor beams.
And the upper finishes are supported by a beam-run, which transfers the load to the internal racks. Stability is ensured by struts, braces and diagonal braces.
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