A very important element that must be considered when the roof is projected, is ventilation, allowing drainage of excess dampness from under the roofing.
First of all, in order to ensure adequate air circulation under the tiles, we must adhere to the following principle: the air inlet must be at least 250 cm2 / m2.
Roof ventilation involves letting the air above the hood and applied ventilation components, such as ventilation tiles that are laid out in the third row from the roof ridge. When the distance between the ridge and the eaves is significant, we should lay tiles even in two rows, and when distance is above 12 meters - in three rows. Recommended spacing between rows of ventilation tiles is about 1.50 m - 1.80 m.
To ensure proper ventilation of the roof, you should also adjust the height of the counter battens, which is dependent on the angle of hipped roof end. Counter battens apply from 25 through 32 to 40 mm, which on the long hipped roof end allows you to keep an adequate distance between the membrane and roof tiles, and thus - the free flow of air.
Keep in mind that proper ventilation affects the proper functioning of vapor-open membrane. When there will be an optimal air flow under the tiles, then the membrane is dried and actually acts as a protective dampness. When we are dealing with a closed space, which causes immobility air, the membrane fails to meet its function. Improper ventilation can also threaten roof wood Fungus and thus weakening the rafter framing.