In warm weather, temperatures can easily reach up to 80° C between the insulation and the roof covering. The hot air spreads to the rooms beneath the roof, negatively affecting the room temperature. In the cold and humid winter months, the external (cold) air meets the internal (warm) air in the cavity between the insulation and the roof covering causing condensation. Only correct air circulation where air enters through the eaves and escapes at ridge level can resolve this problem and prolong the life of your roof.
How to ventilate the roof:
Eaves vents: the air vent section in the eaves line must equate to at least 2% of the relative roof pitch and in any case, must not be less than 200 cm2/m.
Riwega advises 600 cm2/m.
On the ridge and hip: the air vent section in the ridge/hip lines must equate to at least 0.5% of the relative roof pitch in order to increase the pressure and trigger the Venturi effect.
Riwega advises 145 cm2/m. (approximately 25% of the 600 cm2/m opening)
Under the roof covering: the air vent section between the roof cover and the insulation must be more than 20 mm high and no less than 200 cm2/m along the pitch length.
Riwega advises at least 60 mm
