An attic is the space directly beneath the pitched roof on any building. These often awkwardly-shaped areas may be used for accommodation, storage, or passive use. However, they do require adequate ventilation regardless of the application.

Why We Need Gable or Roof Attic Venting

Sealed spaces under pitched roofs attract, and accumulate heat and moisture. These are breeding grounds for mold, which may gradually cause decay in ceiling joists and rafters. Venting the warmth also mitigates against ice dams where the cooler overhangs begin.

The total area of attic vents should be in the region of 1/150 of the floor area of the attic. However, this should be some 50% greater if located in the upper portion of that space. Vents in overhanging soffits typically provide the entry point for outside air.

Two Possible Locations for the Exit Points.

Attic venting occurs when air enters through soffits, increasing internal pressure slightly and causing the moist, warm air in the attic to escape through vents. There are two broad architectural options:

1… Puncture the upper surface of the roof to accept the vents. This may impair the visual impression. Moreover, the vents may leak if not properly installed.

2… Locate the roof vents in gables or dormers if these exist. It’s important to choose locations not facing into prevailing winds, and driven rain in this case.

Choosing Between Gable and Roof Attic Vents

Effective insulation can reduce heat and moisture accumulation. But the architectural design of a building may dictate the final decision.   The overall objective is to ensure an even, steady air flow between soffits, and gable / roof vents.

Some contractors believe a gable vent disturbs this airflow, and this can cause gaps in attic venting. However, the counter argument is a competent installer should either have a workaround, or decline the project.

Architectural Considerations May Have the Final Say

Attic vents in roofs need careful selection. That’s if we want avoid the impression they were added as an afterthought to fix a problem. Gable vents, on the other hand can improve the appearance of a building by adding an attractive architectural detail.

Contact Valiant Exteriors if you have a home or business in the Calgary area. We offer impartial advice, even if it costs us an order. We are the small, privately-owned roofing and siding contractor building a great reputation for quality. And we stand by every job we do.

More Roofing Ideas

Whirly Bird Attic Fans Pros and Cons

Best Gutters for Cold Climates

Image: Louvered Attic Vent in a Gable:  Pearson Scott Foresman BY Public Domain