Does attic ventilation affect how long a roof lasts?
Yes. A poorly ventilated attic can get very hot in a North Texas summer, and that heat can shorten the life of your shingles. Good ventilation needs intake vents low on the roof, usually at the soffits, and exhaust vents near the ridge, so air can flow through the attic.
How attic ventilation works
Air comes in through soffit vents under the eaves and leaves through vents at or near the ridge. Because hot air rises, this creates a steady flow of air through the attic.
If the soffit vents are blocked, often by insulation, adding more exhaust vents will not solve the problem.
Use one type of exhaust vent
Mixing different exhaust vents, such as a ridge vent with box vents or a powered fan, can keep air from moving through the whole attic.
In most cases, one type of exhaust vent per attic space is recommended.
How heat and moisture affect your roof
Heat and moisture trapped in the attic can cause shingles to dry out and wear faster, and can damage the decking over time.
In winter, warm moist air can condense on the underside of the roof deck, which can look like a leak. A hot attic in summer also makes your air conditioner work harder.
Improve ventilation during a roof replacement
A roof replacement is the easiest time to improve ventilation, since the roof is already open.
Ask your roofer to check both the intake and exhaust vents as part of your estimate.
Related Questions
How much ventilation should an attic have?
A common building code guideline is one square foot of net free vent area for every 150 square feet of attic floor, split roughly evenly between intake and exhaust. In some cases the code allows half that amount.
Are powered attic fans a good idea in Texas?
Not always. In an attic without enough intake ventilation, a powered fan can pull cooled air out of your home. Make sure the intake vents are working first.
I see moisture on the underside of my roof in winter. Is that a leak?
It may be condensation. Warm, moist air from the house can condense on a cold roof deck. Better ventilation and sealing gaps in the ceiling usually help.
