Ice Dam Causes & Prevention


Around this time of year we typically hear from homeowners asking for advice on how to prevent ice dams on their roofs. Sure, we haven’t seen any much snow or ice yet, but we all know it’s coming. Here are some helpful tips from our team at Feinmann to prevent you from having to deal with this costly situation.

What causes ice dams?
Ice dams happen when the outside temperature is below freezing, the roof deck temperature is above freezing, and there is snow on the roof. The warm roof deck causes the snow on top of the roof deck to melt, and the melt water runs down to the edge of the roof where the water freezes leading to a buildup of ice and a backup of water, hence the term “dam”.
How can I prevent an ice dam?
To prevent an ice dam, don’t heat the roof, keep it cold. That way, the snow on the roof eventually dissipates without making large amounts of melt water. The underside of the roof deck should not exceed 30 F. The best way to maintain low temperatures is by ensuring that there is adequate insulation and sealing gaps that let warm air pass into the attic from the house. Some contractors are under the impression that attic ventilation is one of the first steps to help prevent ice dams, but one should always start with sealing the attic and increasing the insulation.

Read here for more information on preventing ice dams: or call or email us at Feinmann to come and look at your roof . (781) 860-9800