Everything You Need to Know About Roof Ventilation

Venting a roof seems to be one of the most misunderstood subjects in the roofing industry. Even among industry veterans, there is a lot of misinformation. Sometimes it’s because they don’t really know, sometimes they are just regurgitating old information, sometimes they’re just trying to do the bare minimum.

At Klaus Roofing of Ohio, we not only want our customers to be satisfied with the work, but we also want them to be knowledgeable about why we’re doing what we’re doing.

Why vent a roof?

The intent of venting roofs varies depending on climate, but it is the same if you’re venting the entire attic or if you’re venting only the roof deck.

Cold Climate

In a cold climate, the primary purpose of ventilation is to maintain a cold roof temperature to avoid ice dams created by melting snow and to vent out any moisture that moves from the conditioned living space to the attic.

You never want more ventilation at the ridge than you do at the soffit. This is because when the wind blows, it will suck the air out of the top of the roof and depressurize the attic. This will draw conditioned air out of the house and can raise your heating costs.

Hot Climate

In a hot climate, the primary purpose of ventilation is to expel solar-heated air from the attic or roof to reduce the building’s cooling load and to relieve the strain on the air conditioning system.

Heat does not damage roof shingles, if that were true we would have to turn off the sun. The attic is hot because the shingles are hot, not the other way around. The maximum service temperature for a roof shingle is 240°F, which is an impossible temperature to get to from the sun.

Mixed Climate

In a mixed climate, ventilation serves either role, depending on the season.