Ask most homeowners what makes a roof last, and they’ll say the shingles. Ask a roofer, and ventilation is near the top of the list. It’s the least visible part of a roof and one of the most important. Here’s why.
What roof ventilation actually does
A properly ventilated attic lets cool air in at the soffits (intake) and pushes hot, moist air out at the ridge (exhaust). That constant, balanced airflow keeps your attic close to the outdoor temperature and keeps it dry. When that airflow is missing or unbalanced, problems start.
Summer: your shingles cook
Without exhaust, attic temperatures can soar. That heat radiates into your shingles from below, accelerating the breakdown of the asphalt and shortening the roof’s life. Many premium shingle warranties actually require adequate ventilation, so skipping it can void your coverage.
Winter: ice dams
This is the big one in Winnipeg. When heat escapes into a poorly ventilated attic, it melts the snow on your roof. That meltwater runs down to the cold eaves and refreezes, building an ice dam that forces water back up under your shingles and into your home. Proper ventilation keeps the roof deck cold and even, which is one of the best defenses against ice dams.
Year-round: moisture and mould
Everyday household moisture (showers, cooking, laundry) rises into the attic. Without ventilation, it condenses on the underside of the roof deck, leading to rot, mould, and ruined insulation.
Getting it right
Good ventilation is about balance, matching intake at the soffits with exhaust at the ridge. Too much of one and not enough of the other doesn’t work. When we install a roof, we assess your existing ventilation and correct it if needed, so the new roof performs the way it should.
If your home suffers from ice dams, a hot upstairs in summer, or a musty attic, ventilation is often the culprit. Book a free inspection and we’ll take a look.
