The disadvantages of the roof arrangement adversely affect the strength of the entire building, reduce its life. Roof ventilation is laid at the stage of creating the construction plan. The system serves to remove excess moisture from the subroofing space.
The need and purpose of roof ventilation
Regardless of the material of manufacture, the roof should always be equipped with a ventilation system. If it is missing or mounted incorrectly, the following consequences are possible:
- rotting of the rafter system due to constant exposure to moisture, a fungus appears on the wooden elements, destroying them;
- deterioration of the insulating qualities of the insulation, while heating costs increase;
- the appearance of icicles, blocks of ice on the eaves of the roof;
- condensation formation;
- roofing corrosion;
- humidity increase inside the building;
- overheating of the roofing material (especially detrimental effect on soft materials).
The main purpose of the ventilation system is to remove excess moisture from the surrounding area. In this part of the house, the air should be cool, clean and dry.
Main goals
Roof ventilation performs the main function - removing moisture from the under-roof space. In addition, she solves such problems:
- provides cooling of the roof in hot weather (soft materials are able to melt);
- evenly distributes temperature;
- activates air circulation;
- prevents icing of the roof.
The ventilation system protects the rafter system from premature destruction. Reduced costs for space heating and air conditioning.
Roof ventilation classification
Roof ventilation is forced or natural.
Natural
It is easy to arrange ventilation in the attic rooms. A large volume of air mass circulates there, so a forced construction is not necessary. Each air on the roof provides fresh air from the street. The openings equalize the temperature of the outer and inner surfaces of the roof. In the process of moving air masses lies the principle of convection.
Indoors, the air heats up and rises. Through skate-type vents, he leaves the building. Cold air masses enter through the eaves.
Forced
Ventilation of a roof made of metal is best done compulsory. In its design there is a fan that is mounted in the upper outlet. It is needed to extract warm air. Such a system is desirable if a sufficient number of vents in the roof cannot be made or the project provides for a flat design.
It is better to mount the fan during the construction of the roof. If the design is already ready, the arrangement of the system will cost more. The device needs electricity to function.
Mounting Features
The arrangement of the ventilation system depends on the type of roof and the material used as a roof. The same parameters determine the amount of consumables and the total cost of the structure. Ventilation passages provide the output of internal air to the street. They are selected depending on the roofing material used.Common types of nodes are:
- With valve. Such a product includes a shutter blocking the pipe if necessary. It is rarely installed in a private house. In this case, a device without a valve is more popular. Since there is no partition in it, it will not be possible to adjust the amount of air flow through.
- With thermal insulation. The inside of the exit is finished with fiberglass, stone wool. Thanks to insulation, the temperature difference between the under-roof space and the street is reduced. No condensation will accumulate inside the ventilation system. You can also use the device without insulation if the house is built in a region in which there are no harsh winters, the climate is mild and warm.
- With manual or automatic adjustment. The first type is equipped with a special thin cable, with the help of which the movement of passing air is controlled. An automatic device requires a controller and electronics to function. However, in this case, all parameters can be pre-programmed.
The shape of the holes are oval, square, round or rectangular.
From metal tile and corrugated board
Metal tile is a common material, since it has an acceptable cost, its laying is not complicated. For the installation of sheets, the construction of the lathing is required. It allows air masses to fall into the attic. They go back through the ventilation elements. To ensure natural ventilation, metal pipes are used, placed in a plastic casing. Polyurethane is used to isolate the product. Since the pipe goes outside, it is protected from precipitation with a deflector. Moreover, this element enhances air exchange.
Roof ventilation for a metal tile provides for the arrangement of one exit per 60 sq.m. A distance of 60 cm is maintained from the vent to the ridge. Before drawing up the system, you need to make a drawing of it.
To ensure that the vents are positioned correctly, markings are made on the roof. After the window is cut out, a rubber ring is attached to it using screws. A sealant is applied to it, which fixes the passage element. For greater strength, the structure is best secured with screws.
If the length of the roof slopes exceeds 6 m, and the slope of the roof is shallow, instead of pipes, ventilation connections are installed.
If the ventilation of the roof from the metal tile is not difficult to do, then when working with corrugated board, some nuances are taken into account. This material is practical, inexpensive, presented in a wide range of colors. Used for the construction of simple and complex roofs.
The length of the ramp should not be more than 12 m. Depending on the angle of the ramp, an overlap is determined: 20 cm at 12-15 degrees. In order to organize ventilation for a metal tile or corrugated board, it is necessary to correctly form a subroofing space. Masonry of steam and thermal insulation is required.
Ventilation holes are located at the highest points of the structure. Here, the rule of one outlet for every 60 sq.m. also applies. If the design is complex, there may be more holes. A grill is mounted on the window, which is treated with sealant if necessary.
From soft coating
The soft roof is represented by flexible (bituminous) tiles. This material is often chosen by professionals, since it allows you to realize the most complex and interesting design projects.
Installation of ventilation in this case depends on the type of roof. For a flat design, aerators placed under the roof are required. For the pitched variety, ridge exits are used. They are mounted in the area of connection of the parts of the roof at the highest point.
To begin with, holes are cut out in the roofing material. Previously, marking is applied to it.A plate with a ventilation pipe is attached to the window. Self-tapping screws are not used for fixing. It is better to use silicone sealant.
Mansard roof
To create a comfortable atmosphere in the attic, ventilation is required to ensure high-quality air exchange. It can be carried out naturally through the movement of air masses from the eaves to the ridge. Additional devices are sometimes required.
It is better to entrust the arrangement of ventilation of the under-roof space of a metal tile to a professional, but if you follow the instructions, you can organize it yourself. If the house has a mansard roof, the ideal design option is a valve arranged in the windows. It allows you to ventilate the room even with the sash closed.
An attic roof ventilation valve is available for sloped or vertical windows. At the ridge, air exits through a special aerator.
Arrangement methods
Different methods of ventilation of the hip roof or other types of structures are used. The choice of option is determined by architectural features.
Ventilated cornice
If you can’t arrange ventilation ducts on the overhangs of the roof, you can use a special cornice. It provides good air exchange due to ventilation grilles and spotlights.
If the second option is used for binder, a gap of 1.5 cm is left between the elements. This creates a natural draft of the air flow. In places where there are ventilation channels of the cornice, it is not necessary to lay a heat insulator.
Spotlights - a panel that sheathes a horizontal surface. In appearance, it resembles siding, but differs in its design. On the surface, the spotlight has perforation. The material is fixed along the edge of the ramp directly to the box. The width of the panels is 22-30.5 cm, and the length is 3-3.6 m.
The following types of spotlights are distinguished:
- Solid. They are used for cladding outdoor terraces, verandas. The roof space is well ventilated, while the structure has a presentable appearance.
- Perforated over the entire area. With their help, visors, overhangs and cornices, roof gables are closed. It is better to use them for seam or soft roofs.
- Perforated in the center. When installed, they alternate with products with a solid surface.
Spotlights are plastic or metal: copper, aluminum, steel.
Dormer window
Dormers are installed on the gables, and in their absence directly on the slopes. They are intended for ventilation and equalization of pressure in the attic space with respect to the outside. This allows the roofing to remain in place in the presence of strong gusts of wind.
Dormer windows serve as an additional way of ventilation, since they cannot fully perform this function on their own. There are several types of them:
- Pediment. Such designs are more common than others. They are located on opposite gables on the same roof. Windows come in various shapes.
- Antidromeres. Such structures are placed on slopes and recessed into them.
- Dromers. These windows extend beyond the roof. In addition to the main tasks, they perform a decorative function.
- Attic. They are placed flush with the roofing material.
Any type of dormer during installation requires careful waterproofing. If they are glazed, the ventilation process is carried out only with the leaves open. The design is sold ready-made. The window box is made of wood or plastic.
Aerators
The most common ventilation arrangement is the installation of aerators. This part is a short piece of pipe with a flat base. To protect the product from precipitation, an umbrella with a filter is used. Most aerators are mounted pointwise in the upper area of the roof. The advantage of the design is that it does not affect the overall design of the structure.
In order for the parts of the roofing cake to last for a long time and not give in to destructive processes, the roof should be well ventilated. Ventilation avoids condensation. Otherwise, the humidity level will be increased indoors.
