When Attic Ventilation Becomes a Problem

A vented attic is an important yet highly under-appreciated consideration in roof building. When constructed properly, a vented attic will work in hot, cold, and mixed climates. Unfortunately, inexperienced roofers manage to mess up attic ventilation again and again, and this leads to excessive energy losses, mold, rot, ice dams, and plenty of unnecessary repair expenses.

The way attic ventilation is constructed relies primarily on climate, but its purpose remains the same – to maintain an ideal roof as well as household temperature. In cold climates, ventilation prevents the formation of ice dams and vents out any moisture that transfers to the attic from the living space below. In hot climates, it expels solar-heated air from the attic to reduce the structure's cooling load and reduce the strain on air-conditioning systems. In mixed climates, attic ventilation can serve either role.

Unskilled roofers get this simple approach wrong because they don't follow the rules. Oftentimes, all they do is punch random holes in the ceiling, fill these holes with recessed lights that leak air, and stuff a serpentine array of duct-work in the attic. These holes are a major source of air leakage that causes ice dams in cold climates and humidity problems in hot climates. Hence, for homeowners looking to enjoy energy savings, it's wise to only work with reputable roofers who absolutely know what they're doing. It's essential to determine that a roofer knows proper attic venting before you hire him.