Ice damming occurs when roof heat causes snow to melt and refreeze at the eaves. How can insulation help prevent damming?

• A. Increasing attic insulation and air sealing reduces roof warmth and prevents damming.
• B. Installing thicker carpet helps reduce damming.
• C. Ventilation in the attic alone prevents damming.
• D. Adding more attic fans alone prevents damming.

Answer: (A)

Ice damming happens when heat from inside the home moves up into the attic and warms the roof, melting snow that then refreezes at the eaves. The most effective way to prevent this is to keep the roof cold by stopping heat from leaking into the attic. Increasing attic insulation and air sealing the attic floor reduces heat transfer into the attic, so the roof stays cooler and the snow near the edges doesn’t melt and refreeze.

Thicker carpet won’t impact heat transfer between the living space and the attic, so it doesn’t help with damming. Attic ventilation by itself can help with moisture and temperature control, but it doesn’t stop heat from escaping into the attic. Adding attic fans alone also doesn’t prevent damming, because the root issue is heat entering the attic in the first place, which insulation and sealing address.