The importance of attic ventilation cannot be understated. A brand new a perfectly finished roof will still rot from the inside out if there is not enough ventilation.
In the Pacific Northwest, ventilation is even more critical because of the cold temperatures and large amount of moisture. When replacing an old roof, it is common to find most of the wood sheathing structure of the roof deck to be damaged from condensation caused by lack of attic ventilation.
The roofing industry has used many different tools over the years to try to solve this issue, and we have settled on a very effective method. But when that method is strayed from, ventilation problems can return.
It may make intuitive sense that when there isn’t enough ventilation, to just add more. However, depending on what is added, the ventilation can be made worse.
The most common 5 types of ventilation you’ll see are:
- Continuous ridge exhaust vents (like GAF Cobra)
- Louver (or static or box) vents
- Gable end vents
- Continuous intake vents (like GAF IntakePro)
- Bird blocks
- Have only one exhaust type and one intake type
- Never have more exhaust than intake
- Make sure intake is at the lowest point of the attic and exhaust is at the highest
- Have enough total ventilation