Depending on the type and geometry of the roof, certain materials are selected for its construction. Roofs are: flat (industrial buildings, baths) and pitched (residential buildings and other buildings). Depending on the number of slopes, they are divided into: single-slope (trapezoidal section), double-slope (have the shape of a triangle), half-hip, hip (consist of several slopes), tent (similar to a pyramid), mansard. The number of slopes, the slope of the roof, the presence of an attic - all this affects the choice of load-bearing and self-supporting elements of the roof structure.
Supporting structures
One of the most important parts of any roof is the supports. Rafter legs or trusses can usually rest on:
- the upper crown in houses of timber;
- binding board in frame buildings;
- Mauerlat in stone buildings;
- metal beams, brackets.
Mauerlat is a structural element of the roof, which is a beam (usually with a section of 100 × 100, 150 × 150 cm). It is mounted around the perimeter of the wall in those places where the rafters or trusses will rest. Mauerlat is necessary for even load distribution and the strong attachment of load-bearing structures. Of course, you can do without it, but it provides additional rigidity to the entire roof.
If the house is being built from timber, then the upper crown is used as a support. It has all the necessary fasteners, so load-bearing structures are immediately mounted on it. Frame buildings are assembled by their wooden panels. They consist of vertical boards held by a strapping element. It is to him that the future roof is fastened.
If it is made of metal trusses or rafters, then the channel or I-beam will serve as a support. They can be attached to stone walls with anchors.
Rafter system
The rafter system is a roof element that carries the load of the entire roofing “cake” (coatings, battens, insulation, finishes). Most often, when erecting roofs, rafter legs are used, which are: hanging and inclined.
Hanging structures are based on two points located on load-bearing walls. In such a system, the walls experience horizontal loads, decreasing with metal or wooden puffs. In this way, attic and attic roofs are mounted.
Inclined rafters are suitable for buildings inside which there is an intermediate support (internal wall, column or beam). The other end is located on the outer walls. These mounting options for rafters can be combined with each other: choose inclined, if there are internal supports, and use hanging - if they are not.
Also rafters can be made of metal. For large-span buildings, it is possible to use similar structures under the skates. It should be remembered that the junction of metal with wood should be protected by special means and insulating materials. This is necessary so that the wooden elements do not rot from the condensation formed on the metal parts.
Trusses
Very important and reliable elements of the roof of the building are roof trusses. They are: wooden, metal (welded and prefabricated), reinforced concrete. The choice of material depends on the span of the building and the tested loads. A farm is a set of parts (struts, braces, puffs) that are fastened together.
The most popular are wooden structures that are lightweight, durable, affordable. To connect their parts, use a notch, bolts, nails, MZP. Metal and reinforced concrete trusses are usually used in large-span buildings. They are more expensive, durable and heavy. Metal elements are fastened with bolts and welding.
In modern construction, wooden trusses connected with metal gear plates (MZP) are in great demand. They have a large number of advantages:
- accelerate installation, since the trusses are delivered to the construction site in finished form (manufactured at the factory using a hydraulic press);
- make it easier to finish thanks to its lower belt. A lath is attached to it, and then the lining itself;
- allow to cover the span up to 30 m;
- simplify the assembly of complex roofs (hip, attic, attic).
Additional elements
In order for the roofing to look neat, beautiful and not require constant repair, it is necessary to use additional elements for the roof. They are needed to preserve the integrity of the material, as well as to protect (from moisture, dust) and decorate structures. Most often, such products are made of galvanized steel. However, they can be the same color as the roofing material.
The most popular names of roof elements:
- Cornice strip. It forms a junction between the cornice and the first row of coatings.
- Fronton strip. Closes the junction of horizontal structures with vertical surfaces.
- Skate plate. Hides a hole at the highest point of the roof.
- Endova (for internal and external corners). Closes the junction of intersecting planes.
- Cornice rail. Prevents rain, dust and dirt from getting through the cornice.
- Abutment bar. Protects the connection area of the coating with parapets, pipes, chimneys.
- Snow retention. Prevents snow from falling from the roof.
- Trumpet. It is a smooth sheet that decorates the chimney box.
- Lightning conductor and grounding. They protect the building from lightning.
- Window tide. Closes joints along the perimeter of window openings so that moisture does not penetrate through them.
- Plugs for gutters, skates, etc.
- Small parts (various seals, gaskets, etc.).
- Decorative products (wind indicators, spiers, tips of chimneys, ventilation, parapets).
Dormers and aerators
The main task of both elements is to ventilate the space inside the roof. This is necessary so that the insulation does not rot. The minimum size of dormer windows is 1.2 × 0.8 m (with two wings). Balconies can be attached to large-span structures. The step of the openings is at least 800 mm. Their total width should not exceed half the length of the building.
Dormers - roof elements that are installed in slopes with a slope of 35 degrees. Outwardly, they resemble separate structures that have their own walls, roof and drainage system.
As for aerators, they can work according to two principles: create draft in the pipe or be included in the work due to different pressure inside the roof and on the street. Without these small elements, air cannot circulate normally in the interroof space. As a result of their work, the structures do not freeze, do not thaw, and are not covered by moisture. This extends their life.
According to the method of ventilation, aerators are divided into point and continuous. The latter are located along the length of the ridge, and apparently they are invisible. Point elements are installed on slopes (indented from the top of the roof no more than 600 mm) or on the ridge.
Gutter system
Another important element of the roof of the building is the gutter system. It consists of the following components:
- Gutters. With their help, streams of water flow in the right directions.
- Pipes Thanks to them, precipitation falls into the drainage system.
- Funnel. Through them, water enters the pipes.
- Stubs. Used to restrict flow.
- Fasteners. Pipes are fastened with clamps, and the gutters with brackets.
Depending on the material, gutters are plastic and metal. The most popular today are plastic products. They are light in weight, attractive in appearance, and also easy to install and serve for a long time. Metal gutters are also in demand. They are made of galvanized steel, which is coated with a polymer coating. The main disadvantage of such products is their low resistance to mechanical stress (scratches, impact loads).
Roofing material
Roof coatings are: rolled (roofing material), sheet (metal) and piece (ceramic and flexible tiles). Roll materials are inexpensive, last a long time and are easy to assemble. A solid flooring is used as the basis for them, which makes the surface as flat as possible. To fix the material, bitumen mastic is used, heated by a burner or blowtorch. Products are stacked in several layers, coming with an offset.
Sheet material can become an element of a wooden roof or any other. This group includes: metal tile and corrugated board. Under them there should be a crate, the pitch of which depends on the wavelength of the product (usually 300-400 mm). Decking is in great demand due to its low cost, ease of installation and attractive appearance. Both materials can be fastened with self-tapping screws with or without seam seams. The first option is considered more reliable, since the stiffness of the roof increases.
Ceramic tiles are beautiful, durable, but very heavy and expensive. That is why it is not so common. Another piece of material - flexible tiles - is more popular today. It is made in different colors, as a result of which the coating looks voluminous and very solid. If it starts to rain, the coating will drown out the drops (which cannot be said about the metal tile).
Protective films
If the roof will be insulated, it is necessary to protect the thermal insulation with steam and windproof films. Under the sheet material will have to lay waterproofing. All these films will protect from moisture, condensation and decay. Waterproofing and windproof coatings are combined today in one product. Let's get to know each of them better.
Waterproofing placed under the cover protects against condensation. It is also used in the installation of ventilation - it prevents water from entering the system. Waterproofing passes air well, but does not let moisture through it. If condensation builds up inside the roof, over time the supporting structures will begin to rot or rust. The film is attached to the roof truss element, after which counterrails and lathing are nailed. Do not pull it too much - it should sag a little.
Vapor barrier is used only in insulated roofs. It closes the insulation on the inside of the room. It can be located in horizontal and vertical position (for example, in attics). If this film is not laid, the insulation will get wet and cease to normally retain heat. It is mounted using small nails or a construction stapler. Between the vapor barrier and the thermal insulation a gap of 100 mm is laid.
Thermal insulation
To such an important element of the roof as thermal insulation, a number of requirements are imposed. It must be lightweight, environmentally friendly, durable and fireproof. It is very important to protect the insulation from moisture so that it does not lose its properties.
The most popular thermal insulation materials:
- Styrofoam. It is lightweight, durable and is most suitable for flat roofs.
- Polyurethane foam. It retains heat well, is durable and light.
- Glass wool. It is made of molten glass or its waste. The material absorbs sounds well, does not absorb moisture, is not afraid of frost and does not crumple during operation.
- Minvata. The structure of its fibers can be different: layered, spatial, corrugated or vertically layered. The material retains heat well, absorbs sounds, is not afraid of moisture, rodents and temperature extremes.
Interior decoration
There are several options for finishing the roof from the inside. Usually these works are done in attics or in warm attics. As a covering, you can use: drywall, lining, plywood or OSB-boards.
Drywall decoration begins with slopes and pediments, after which they move to the ceiling. The crate, going with a step of 1 m, will help to facilitate the work. Additional bars are nailed horizontally (step 300-500 mm). After this, drywall is fixed with screws to the prepared surface. It is leveled with putty (in the area of the holes) and primed.
Lining can become a good element of the roof. It is cut and attached to the crate with the help of nails. It is necessary to constantly check the levelness of the surface level. As soon as the last element is fixed, the lining is varnished.
Another option for interior decoration is the use of plywood. It aligns the surface well, after which it can be coated with paint or wallpaper. As a casing, it is best to use moisture-proof plywood so that it does not suffer from accidental leakage. The material is attached to the crate using nails or self-tapping screws. Work begins with gables and slopes, and then go to the ceiling.
OSB-plate can be mounted directly to rafters and trusses (an additional crate is not needed). Before finishing, the surface is leveled, and then a sheet is fastened with screws. Additional alignment is not needed if the rafters are made of polished boards.
Attic device
Attic can be completely different, but the main elements of the roof will remain almost the same. In addition, their arsenal is no different from ordinary roofs.
Depending on the number of skates, the attics are divided into:
- Slippery. Such a building has one wall high and the other low. However, both of them can go at an angle. Installation of identical walls with a single-pitch farm is possible.
- Gable. Such attics are very common because of their reliability and easy installation.
- Broken. This option is used if you need to build a small building.
- Hip and semi-hip. Such roofs are in demand due to a more rational use of space.
- Conical, pyramidal and domed. They are found in buildings of a polygonal or rounded shape. Attic look beautiful, but difficult to build.
It may seem that the roof does not have many components. But you should take a closer look to make sure the opposite. Moreover, all the elements perform certain functions, which makes each of them indispensable.