3 Reasons Why Good Attic Ventilation is Important for Any Building

When it comes to roofing, regardless of whether it’s steel or shingles, residential or commercial, the air circulation underneath the roof is just as important as the outside surface of the roof. Here are three factors that come into play with attic ventilation.

Energy Efficiency.

Ventilation is used during the summer to vent heat out of the attic, reducing air conditioning costs. For many years, building science experts were focused on reflectivity as a way to keep heat out of the attic. While reflective or “cool roofs” are still a good idea, tests have shown that good ventilation, which quickly removes any excess heat back out of the attic, is equally, if not more effective at home energy efficiency.


A great deal of moisture is generated inside of a home’s living space. It is generated primarily by laundry, showers and bathing, houseplants, cooking, and ventless stoves. That moisture, originating in the living space of the home, migrates upward and, if a 100% reliable vapor barrier is not installed behind the home’s ceilings, it ends up in the attic. Once it’s in the attic, if that warm, moisture-laden air reaches a cool surface, it condenses. (Like the exterior of a cold beverage outside on a hot, humid day.) The resulting condensation can create a very unhealthy environment, prone to support mold, mildew, and other biological growth. A well-vented attic also helps to keep your attic’s insulation dry, increasing its effectiveness. As insulation gains moisture over time, it loses considerable R-Value and effectiveness.

Ice Dams.

For homes in northern climates, good attic ventilation can help minimize the potential for winter ice dams. Ice dams occur when warm air from the living space reaches the roof deck (the underside of the wood paneling sitting under the shingles or steel paneling. When this warm air reaches the decking, it causes the snow to melt. The melted snow then runs down the roof and refreezes over the home’s cold overhangs, creating damaging and dangerous ice dams. These dams often cause melted snow to leak into the home. When attic ventilation is balanced well, the attic is the same as outside temperatures, during any season. In winter, it helps prevent the snow load on the roof from melting.  For metal roofing, there are snow guard accessories – rails or clamp-on stops to help prevent the dams from forming.

Have you taken a look at the attic in your home lately? It’s always good to inspect it from time to time, just to look for any potential water stains, which may indicate either leaks or moisture from Ice Dams. Feel free to leave any comments or suggestions from any situations that you have experienced in the past, and thanks for reading.