Rafter system (85 photos) — step by step installation instructions. The device and construction of the roof for the house
The roof serves as a reliable protection of the premises from various natural phenomena. It is a basic element in the construction of a private house. The truss system is the supporting frame of the roof, on which a great weight and load is placed: wind, snow, frame. In order to avoid trouble during operation, the roof must be reliable and strong.
The rafter system is the basic part of the roof, it affects the strength of the roof itself, resistance to weather changes. The design is influenced by the shape of the roof and the plan of the private house, as well as the details to be used.
The truss system, which they perform themselves, is most often made of wood, but other roofing materials are sometimes used. Before starting the installation of the truss system with your own hands, you need to prepare well theoretically.
Brief content of the article:
Roof and roof
It is very important to distinguish between the words «roof» and «roof». Roof — consists of rafters, roofing, insulating parts, encloses the house from above. Rafter — a beam that creates a slope, the supporting system of a pitched roof.
The roof is the upper shell of the roof, which is made from various building materials. It is from the roof that the reliability and practicality of operating the house depends.
For the effective installation of the rafter system, it is necessary to act in accordance with certain standards, without which the structure will not be practical.
Particular attention should be paid to the strength of the system, which must withstand the full load. To check the truss system for strength, you need to carry out an approximate calculation.
The second condition is rigidity. The roof system of the building should not sag too much. The rafter system should not be heavy, the load on the foundation and walls should be minimal. Wood is most often chosen as the base material because it is relatively lighter than other materials and quite strong.
Also an important feature is the choice of material for the roof, which should not be heavy. Now less and less often choose tiles, which are made of ceramics. Under this material, all elements of the structure of the house must be well reinforced.
The wooden structure is made only from high-quality raw materials. For the manufacture of basic elements, a tree of 1 or 2 grades is used. Coniferous wood is most often used for the installation of pitched roofs. This type of wood contains resin, so it rots less.
Be sure to use an antiseptic before starting work. This will help you avoid various troubles. Most often they buy wood in the northern regions. It is this wood that is considered the best.
Elements of the roof truss system
The design of the truss system consists of various elements. The main components of the roof are: slopes, cornice and ridge. The top element of the roof is the ridge. The overhang (cornice) is the lower element, and the slope is located between the cornice and the ridge. Load-bearing elements are also referred to the truss system.
The load-bearing elements of the truss system include:
Mauerlat — is the basis for fastening the rafters, it is laid along the perimeter of the walls. It fits so that the load is even. For the manufacture of Mauerlat, a beam of 20cm * 20 cm or 15 cm * 15cm is taken (for small structures).
Inclined beams, with the help of which the load from the roof, wind and snow is transferred to the Mauerlat structure, are rafter legs. They are most often mounted from the ridge to the eaves.
The beam on which the details of the roof rest is a run. The diameter of the run is affected by its span, most often 20 * 20 cm is taken.
Also, the composition of the truss system of a wooden roof includes: struts, racks and puffs. Their main function is to reduce the severity of the basic elements.
An element of the truss system is also a farm. The composition of this design includes: puffs, rafters, racks, struts. The truss is built in the shape of a triangle, due to which it has good stability.
The connection nodes of the truss system are of the following categories: the connection node of the Mauerlat and legs, the connection node of the elements of a wooden truss and legs.
The method of connecting the Mauerlat and the rafters is sliding and rigid.
It is not always possible to use hard corners, because wooden elements are subjected to deformation from the influence of the environment and it is not always appropriate to use a rigid coupling of layered systems. A system of sliding corners is used to build layered rafters.
The presence of a drawing of the truss system, where all structural elements are indicated, will effectively help in working on the system.
The drawing is shown below.
Roofing on pitched roofs can be of the following forms:
- broken lines.
With a shed roof truss system, the simplest design is made, its slope is 14-26 degrees, here the layered rafters rest on load-bearing walls.
The roof in a gable truss system should be with a slope of up to 60 degrees.
The roof with a hip roof truss system should also be tilted up to 60 degrees. This type of roof is more difficult to install, but the cost will be much lower since there are no front walls. For the installation of a hip roof, truss trusses or layered rafters are used.
With a mansard (broken) shape of the roof, the span is 10 m, and the lower roof area is at an inclination of 60 degrees, thanks to which the size of the attic can be increased. The span between the outer walls, according to the recommendation, is made no more than 10 m.
The differences between the forms of roofs are shown in the photo of truss systems in the gallery at the end of the article.
For the construction of mansard roofs, parts are most often used. The main functions that the connections of parts perform:
- ensuring that the load is transferred in the right direction
- withstand physical stress
- guarantee of operation
At the moment, the following building materials are used to connect elements in the truss structure: studs, metal plates, bolts, self-tapping screws.
For fixing parts that are made of raw wood, studs or bolts are most often used.
roof ventilation system
From a warm room to the attic, very often flows of water vapor pass, which creates condensate on the roof coverings. Wooden parts and insulation suffer from condensation.
Ventilation is done to eliminate moisture in the rafter system and in the attic.
Water vapor that enters the attic must exit without obstacles through the windows and special holes that are made in the roof ridge.
In houses where flat roofs and attics are used, there should be a space with ventilation.
Roof covering installation
Pitched roofs are covered with hard (asbestos-cement sheet, polymer or ceramic tiles, corrugated board, etc.) or soft materials (bituminous tiles). Most often, rigid materials are mounted on a wooden frame.
Rigid sheets of roofing are most often laid on a crate of wooden bars.
When installing each truss system with your own hands, it is necessary to firmly mount all nodes and connections. It is important to make not only the correct frame, but also it is practical to choose the material for the roof. The roof is the most important protection of the house from various bad weather.
Photo of the truss system
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Post published: 29.11
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