Absolutely any building requires the construction of a roof, and the final result, expressed in its reliability, durability, and ability to withstand any vagaries of the weather, depends on how familiar the developer is with the basics of the construction of such structures. The structure of the roof is not as simple as it might seem to someone at first glance. It consists of many details and elements, requires competent calculation and the same execution.
Features of some types of roofs
There are 2 main types of roofs:
- pitched;
- flat.
Both from the point of view of construction and from the point of view of the materials used, the differences between these types of roofs are significant.
Flat type roofs are usually arranged on top of industrial buildings, as well as on high-rise buildings, while pitched roofs, as a rule, are crowned with low-rise buildings - 2-5-story houses: cottages, summer cottages, some Khrushchev houses and other types of structures. The most common type of pitched roofs are classic gable roofs.
With sufficient desire and skills, flat roofs of small structures such as garden houses, arbors, and sometimes private houses, may well be built by hand, even if you decide to carry out the entire list of work alone.
As for the device of a pitched roof, it will be quite difficult to operate here with one pair of hands, and if possible it would be better to invite 1-2 assistants to help.
Required roof pitch
The device of the roof of a private house, as well as buildings of a different kind, assumes the presence of a slope. The slope of the roof is chosen, guided by the following set of rules:
- In roof slopes, the slope can be from 5 to 60 degrees, depending on the type of roofing material and on the calculated snow load - the higher the snow load is expected, the steeper the slope should be, respectively.
- As a rule, in areas with moderate and high rainfall, the slope is chosen to be about 45 degrees.
- In areas where frequent and strong winds are observed, on the contrary, large slopes should be avoided due to the fact that the wind load can have a destructive effect on the roof.
- Among other things, the slope of the roof also depends on the chosen roofing material.For piece materials (slate, tiles and others), it is taken equal to at least 22 degrees, otherwise water can seep at the joints of individual elements.
Flat roof device
- We should not forget that the value of the selected slope is directly proportional to the total cost of the roof. With an increase in the slope, the consumption of materials also increases, and consequently, the overall estimate. Therefore, when choosing a slope, it is necessary to strike a balance between all requirements and components. For gable metal tile roofs the optimal limits for the slope of the roof are 20-45 degrees, for sheds - 20-30 degrees.
External roof structure
The load-bearing elements of the roofs are made of boards, beams and logs. Based on the materials used, the method of connecting the individual elements of the roof is determined.
The external structure of a complex hipped roof consists of the following elements:
- stingrays;
- skate;
- hip;
- grooves;
- gables;
- gable overhangs;
- gutters;
- drainpipes;
- chimney pipes.
Internal roof construction
As for the internal structure of the roof, here the main role is played by the device of the roof frame, which is represented by the supporting roof truss system, consisting of rafters, battens and Mauerlat.
Moreover, in a structure such as standard slate roof, such fasteners as racks, crossbars, struts, racks and others can be included. All of them are applicable to make the truss truss more rigid.
The composition of the supporting structure of the roof is as follows:
- racks;
- crossbars;
- rafter legs;
- overlaps;
- struts;
- Mauerlat;
- grandmas;
- spacers;
- runs;
- puffs;
- beams.
The device of the truss system
The need for the use of additional structural elements appears with an increase in the span. The truss truss is formed by separate parts of the roof, which are interconnected.
The truss is based on the use of triangular fasteners, since this figure gives the structure the greatest rigidity.
A wooden beam, which is placed in the cuts of the outer walls, is called Mauerlat. It serves as a base for the supporting rafters. The mauerlat is attached to the walls by means of metal brackets and coupling bolts.
The roof construction scheme may involve the use of one of two types of rafters:
- hanging;
- layered.
Laminated rafters are applicable in the roofs of houses with medium supporting walls. The span between the supports is usually up to 4.5 m, and with an increase in the length of the spans up to 6 m, struts are installed under the rafters.
Do-it-yourself roof rafters of this type with their lower ends rest against the Mauerlat, through which the load from the weight of the roof structure is transferred to the wall.
Such a support scheme provides for the transfer of not only vertical, but also horizontal loads to the walls. The load appears due to the work of the rafters by surprise, therefore, the use of layered rafters is recommended in buildings with massive walls that are able to perceive and withstand the expansion load emanating from the rafters.
Hanging rafters are used less often, as they require even more careful manufacturing of nodes, especially screeds. The advantage of such rafters is the absence of horizontal load transfer to the walls, as well as their ability to cover large spans.
Roof insulation and waterproofing
After the construction of the roof frame is completed, they proceed to its insulation and waterproofing. Particular attention should be paid to materials used for roof insulation and waterproofing and located in the under-roof space.
As a heater, mineral-cotton basalt slabs, slabs of expanded polystyrene and glass wool at least 15 cm in thickness can be used. They will keep the attic warm in the winter and prevent it from overheating in the summer.
To protect the insulation from moisture, it is covered with a waterproof film that forms a continuous waterproofing layer. With a large amount of moisture, it will be able to flow down the film to the street, and with a small amount, it will evaporate and be removed with the air flow to the street through the under-roof ventilation system.
This system is very effective in combating dampness.
The air-conducting under-roof space is formed by structural elements such as a batten and a counter-batten.
The counter-lattice is nailed in the longitudinal direction over the rafters. In the transverse direction, a crate is attached to it, which is necessary for laying the roofing.
Under roll-type roofing materials, the crate is made in the form of a continuous flooring, under piece - in the form of a lattice.
Roof decking
Roofing installation rules:
- Any type of coating is laid in dry and warm (moderately warm) weather.
- Roofing material is lifted onto the roof neatly one sheet at a time.
- The flooring starts from the bottom row, while moving from right to left.
- The material is strengthened by various methods depending on its properties. For some types, nails are applicable, for others, screws or special clips.
Advice! In no case should you save on fastening, since this is fraught with inevitable roof leaks.
- If there is not enough length of material for laying the last row, the sheets are usually cut with a grinder to the required length.
- Laying roofing material implies the obligatory observance of overlaps of a certain length for each roofing material. The amount of overlap depends not only on the material, but also on the slope of the roof. The smaller the slope of the roof slope, the greater the slope should be provided.
Among other things, the roof construction scheme assumes the presence of other elements on it: windows, stove, chimney or ventilation pipes, valleys, skates, fence gratings, antennas, snow retention and drainage systems.
Each of them can be provided both to improve the appearance of the structure, and to protect the roof.
Did the article help you?