Why roof ventilation is needed

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Roof ventilation: recommendations for calculation and installation
Roofing materials reliably protect the building from snow and rain, ensuring dryness and comfort in the interior. But the trick is that moisture attacks not only from the outside, but also from the inside. In the second case, its negative impact can only be neutralized with the help of roof ventilation.


There are two reasons to worry about installing roof ventilation:

Living spaces always contain a significant amount of water vapor, which is formed as a result of breathing and sweating of residents and pets, cooking, hygiene procedures and other processes chinese overseas british data with the use of water (washing, cleaning, washing dishes, etc.).
Roof covering is by definition vapor-impermeable, so it is not able to provide vapor release.
Without taking special measures, water vapor rising with warm air would condense on the inner surface of the cold roof covering, with the subsequent occurrence of many negative processes:

wooden structures would rot as a result of getting wet;
the heat insulator, if mineral wool or another hygroscopic material is used in this capacity, would become saturated with moisture, losing its heat-insulating properties;
the roofing material itself would also be damaged - either due to rust, if we are talking about a metal covering, or due to mold, if the roof is covered with ceramic tiles;
In winter, water would form ice, destroying various elements of the roof and pipes, shafts, etc. running through it.
In the absence of ventilation in the attic space, the elements of the rafter system become covered with ice

To prevent all of the above phenomena, roof ventilation is installed, which implies the presence of a blown gap and ventilation of the attic space.