Monday, December 22, 2008

Ice Dams + Attic Insulation


Last winter we had a series of snow storms where I live in the northeast, in Wilmington, MA. The snow piled up on the roof each day, as I tried to remove most of it with a roof rake/shovel, although some snow remained higher up on the roof. The storms were followed by several days of fluctuating temperatures above and below freezing.

This temperature fluctuation caused the roof snow higher up to melt during the day but then freeze along the roof edge at night. This ice then backed up under the shingles to form an ice dam. The ice traveled under the shingles, melted and then dripped down and stained the ceilings below.

I tried to fix the problem by chipping the ice with hammer and chisel, as I stood on a ladder. Although this helped with the immediate problem, more ice dams formed with successive snow storms.

Looking for a solution, I searched the internet for some answers and found some solutions that I hope will help this winter. All the solutions centered on preventing heat from the house below to melt the snow on the roof above. Thus, if there is no melting snow there will be no ice dams.

The solutions included putting in air vents along the eves to increase air circulation under the roof and keep it cold. In addition, I added more insulation in the attic so less heat would escape from the house below and not heat the roof above. To prevent the insulation from blocking air circulation coming from the eve or soffit vents, I installed Styrofoam baffles between the rafters. I also repaired the roof gable vents with new screening and installed an automatic fan over the gable opening. The fan is thermostatically controlled and set to keep the attic cool by pulling in air from the eves, up to the roof ridge and then out the gable vents. Lastly, I bought a 4x8 sheet of insulated Styrofoam to fit over the pull down stairs leading to the attic. This helps with heat loss through the stairs opening. I also taped the edges of the Styrofoam with box tape since it shreds and makes a mess.

The following links below will give you more information about ice dams or installing insulation as well as some photos of my installation project ……..

Ice Dams
http://www.extension.umn.edu/distribution/housingandclothing/DK1068.html

Attic Insulation
http://www.thisoldhouse.com/toh/article/0,,212235,00.html

Project Photos
http://picasaweb.google.com/markryan312/IceDams11108?authkey=6mjRDHVzRJk

Comments are always welcome. Have you had similar roof problems. Send me an email at markryan82@comcast.net.

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