Attic Ventilation in Gatineau: The #1 Reason Roofs Die Too Soon

The attic needs to stay close to outside temperature, summer and winter. In summer, this prevents solar heat from cooking shingles from below (which weakens them and shortens lifespan). In winter, it stops house heat from rising into the attic, melting roof snow, and creating ice dams.

The system only works when air circulates: cold air intake at the soffits (bottom of roof) and hot air exhaust at roof vents or ridge vent (top). It's a chimney effect — hot air rises naturally, cold air takes its place. If either side is blocked, the system fails entirely.

Test 1 — hand at the soffit: on a windy day, hold your hand near a soffit looking up. You should feel slight suction toward the attic. No movement = blocked soffit.

Test 2 — attic inspection: in mid-summer, climb to the attic. Temperature should be within 5-10°C of outside. If you find 50°C while it's 28°C outside, ventilation is inadequate.

Test 3 — winter inspection: after a snowfall, compare your roof to neighbours'. If yours has melted patches while theirs keep uniform cover, your attic is warmer than normal (= bad ventilation or bad insulation).

Some companies sell 'powered attic fans' as a magic solution. Reality: these fans create depression in the attic that can pull warm air directly from the house through insulation — opposite of the intended effect. Passive ventilation (soffits + ridge) is almost always sufficient and preferable.

Edge case where mechanical makes sense: exceptionally complex attics with multiple return angles where natural convection fails. Rare in standard residential.