Ventilation of the roof of the house, the device of the

The worst enemy with whom every homeowner has fierce battles is moisture. Water is a condition of well-being both for us, and for microorganisms and fungi, whose destructive action leads to the appearance of rot or mold. It is able to penetrate both outside in the form of precipitation, and from the inside in the form of condensate vapors, which are products of human activity. To extend the life of a private house with a heated attic, it is necessary to ventilate the roof, which will be the first echelon of the fight against dampness.

Forced ventilation tasks

Creating a roofing cake at home with a heated attic, experienced builders follow the principles of absolute tightness, that is, have the materials in several layers, and even whipping on each other. Such a system ensures protection against moisture penetration and heat retention inside the room. However, it also becomes a big obstacle to the hood. Forced ventilation of the roof of a private house, mounted in accordance with the requirements of SNiP, solves the following tasks:

1. Displays heated air, saturated with water vapor, formed in the premises of the lower floor to the atmosphere. Without effective extraction, it is deposited on the elements of the truss structure in the form of condensate.
2. Warns the appearance of excessive dampness, musty or unpleasant odor inside a residential attic. Ventilation of the roof of the house provides a natural flow of fresh, oxygen-rich air from the atmosphere, which has a beneficial effect on the microclimate.
3. Reduces the heating of the roof surface in the summer. Using a properly equipped hood of a private house minimizes the heating of the roof surface, which makes living conditions in the attic comfortable even on days when solar activity is above average.
4. Protection against ice crusts on the roof surface. Due to the temperature difference outside and inside the heated house, the snow on the roof surface constantly thaws, forming frost, cleaning of which is a labor-intensive and lengthy process.
5. Preservation of thermal insulation properties of insulation. An increase in the moisture content of the insulation as a result of the appearance of condensate by 5-10% increases its thermal conductivity by 35-50%, moreover, this indicator does not return to its original value even after complete drying.

Note! According to the building codes and requirements of the SNiP, the attic is legally recognized as residential only if it is equipped with a forced ventilation system, and the total area of ​​the ventilation vents is at least 1/300 of the roof surface area.

Roof ventilation equipment

Forced roof ventilation is subject to a simple physical law - the principle of convection. Thanks to him, lighter, warmer air rises, freeing up space for cold, atmospheric air with a greater mass. To ensure the exhaust according to the requirements of SNiP are necessary:

• Curtain Airways, через которые под крышу с мансардой проникает свежий воздух с улицы. Продухи изготавливают из обычных пиломатериалов, прикрепляя их с небольшим зазоров или используют специальные устройства – софиты. Софиты – панели с частичной перфорацией из металла или пластика, через которые воздух легко проникает внутрь помещения.
• Dormer windows, which also serve to facilitate the access of air and exhaust. The main feature of this element is that it is used only if the attic of the house is unheated and not used as a living space.
• Ridge aerators. A perforated ventilation element that is installed along the ridge of the skylight roof. Through it, the heated air from the room comes out.
• Pitched deflectors. This is a kind of ventilation pipes on the roof, located on the slopes. They are a tube of diameters of 20-50 mm, passing through the thickness of the roofing pie and protected by a mesh and a cap.
• Modular roofing material. The roof in the form of individual tiles is laid with gaps through which air circulation occurs. From the point of view of ventilation, such materials are much better suited for roofs with heated attic than soft roofing tiles based on bitumen and sheet roofing.

Equipment ventilation heated and unheated mansard roof is significantly different. For a non-residential attic, it is sufficient to leave two dormer windows and an eaves outlet. For a residential attic requires a more complex system of roof vents, a ridge aerator, curtain rods. The required number of ventilation holes recommended by SNiP is calculated based on the surface area of ​​the roof, 1-2 pcs. on 25 square meters. m

Roof deflectors

In order to get the heated air out of the attic room, and the excess moisture from the roofing pie evaporated, roof deflectors are installed on the roof slopes. They consist of the following elements:

1. Housing The body of most aerators resembles a bottle consisting of two parts. The lower part of the body is mounted in the roofing cake at the stage of its flooring, and the upper part is put on after completion of the work. The case diameter usually varies between 30-50 mm.
2. Protective filter. A mesh or sponge filter is located inside the aerator housing. It is necessary to protect it from debris inside the ventilation and prevent congestion.
3. Protective umbrella. The umbrella is put on the tip of the pipe body to protect the aerator from moisture penetration during precipitation.
4. Flange. Silicone or rubber apron to ensure the tightness of the seam between the deflector and the roofing pie. Experienced craftsmen note that more than 90% of leaks through the roof of a new house are due to careless installation and insufficient waterproofing of the roof ventilation elements.

Roof deflectors размещают на высоте 50 см от конька, то есть на верхней части крыши, чтобы теплому воздуху легче было выходить наружу. Средняя стоимость качественного дефлектора составляет 260-300 рублей. Учтите, что минимальное количество этих элементов вентиляции даже для крыши, площадь которой менее 25 кв. м, 2 штуки.

Rules for the placement of ventilation elements

In order for the roof ventilation system to work properly, forcing the air to circulate inside the attic room, you need to follow a few simple rules:

• The height of the ventilation pipe above the roof of the house, as recommended by SNIP regulations, is 50 cm.
• If the pipe is located at a distance of 50-150 cm from the ridge, then it should rise at least 50 cm above it or more.
• If the ventilation pipe is located at a distance of more than 3 m from the ridge and is closer to the ledge, then its height must be such that it is flush with the ridge.
• On a flat roof, the pipe should rise above the surface by 50 cm or higher.
• The ventilation pipe located in close proximity to the chimney pipe must be of the same length.
• The more slopes, valleys and fins on the roof, the more complex its configuration, the more ventilation outlets are required to ensure effective exhaust.
• In areas with a harsh climate, ventilation ducts should be warmed to avoid freezing during periods with negative daily temperatures.
• The main rule of installation of ventilation aerators is to ensure absolute tightness, since moisture can penetrate at the joints, destroying the roofing cake and the roof truss system.

It is better to calculate and determine the roof ventilation equipment before starting roofing, to avoid mistakes and alterations, spoiling the aesthetic look of the house. Well, if you pick up all the items from the range of one manufacturer, optimally complement each other.

A well-equipped roof ventilation protects the roof from premature destruction, makes the microclimate inside the premises pleasant for the person and rationally distributes heat. Its installation is relatively inexpensive, especially considering how much money it will save by increasing the service time of the mansard roof and interior decoration.

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