Roof Ventilation

A ventilated attic works like a chimney. Cooler outside air enters low, usually through soffit vents under the eaves. Hot, moist air leaves high, through ridge vents, roof vents or gable vents. When intake and exhaust are balanced, air moves continuously and the attic stays closer to outdoor temperature.

When that flow is blocked or unbalanced, heat and moisture build up. Common causes are soffit vents covered by insulation or paint, too few exhaust vents, or mixing different exhaust types that end up pulling air from each other instead of from the soffits.

In Texas, the main enemy is heat. Moisture matters too, especially along the Gulf Coast, where humid air that reaches a cool deck can condense. A working system handles both, all year, without anyone having to think about it.

The best time to fix ventilation is during a roof replacement, when the deck is open and ridge vents can be cut in cleanly. Shingle manufacturers, including Owens Corning and GAF, publish ventilation requirements for their products, and a poorly ventilated attic can affect the manufacturer's warranty. That alone is a reason to treat ventilation as part of the roof, not an add-on.

Ventilation can also be corrected on an existing roof. Adding intake, replacing worn vents or removing a conflicting vent type is often a modest job compared with the shingle damage it prevents. If your roof is showing early wear, compare that with our asphalt shingle roofing page to see what to expect from a healthy roof.

Bathroom and kitchen exhaust fans deserve a look as well. When they vent into the attic instead of through the roof or a wall, they add moisture right where it causes damage. Routing them outside is a simple fix that protects the deck and insulation.