Where comes the water from we are fighting against
Human body, as it contains of 70% of water, shares this water with the environment. During any activity (even sleeping) people produce some amount of vapor. These vapors permeate through the attic to the thermal insulation if we do not prevent them from doing that. Roof ventilation conveys all the vapors under the roofing layer where the air circulates and away from this space through the exhaust roofing vents.
Natural and forced ventilation
The roof ventilation (air circulation) under the roofing layer (shingles, tiles) is automatic, as the warmr air always rises up, is exhausted by the exhaust vents and as there is the und...
The pitch of the roof factor
It is really hard to achieve the proper air rotation mainly in the roofs with low slopes, because the vertical distance between the lowest part of the roof and the highest part of the roof is low.
Because of this, the minimum roof pitch of 5% is recommended to vetilate your in-roof space as good as possible.
The surface of the roof
The less of the roofing surface together with the steeper slope - the thinner the air insulation layer has to be.
The more of surface and the flatter roof - the thicker the in-roof air insulation necessary.
The isulation air layer volume
The more insulation air in your roof you have - th...
How the roof venting works
The principle of roof venting is as follows: with the help of sun the air inside of the roof is heated. Based on difference in temperatures of the air layer and the exterrior it comes to the rising (ascending) hot air stream that tends to be exhausted by the vents placed in the upper part of the roof (usually the ridge vents or venting fans placed near the ridge line).
In the second step of the same process the fresh (and colder) air is taken in through the intake vents (soffit intake vents usually).
This is very important as the hotter air can absorbe more water (vpour) and when contacted with the cold surface, the vapour would condensate (bec...
