Updated: Jan 18
To begin, what are Ice Dams and how can you tell if you have them on your house?
A simple tell-tale is excessive icicles that form on the eaves and overhangs of your roof.
Ice dams form because water, which freezes in your gutters, prevents melting snow from your roof to properly drain. When the temperature outside remains freezing, there is no issue. But when the day warms up water melting can pool behind the ice, seep under the shingles, then freeze again. Eventually, it can find its way through the roof and, walls, ceilings.
Ice dams are caused by three conditions:
Air temperatures below freezing.
Roof covered with a thick layer of dry snow.
Escaping heat from the building through the roof.
Seal all points where warm air leaks from the living space into the spaces immediately below the roof sheathing. Also seal any openings in your attic where heat can escape.
Insulate the living space well enough to prevent conduction and convection of heat through the ceiling. Insulate attic and all ductwork.
Install (if you don’t have already) a ridge vent and soffit vents. These will help circulate cold air beneath the roof.
Make sure your gutters have been cleared from leaves and debris to allow water to flow when ice melts.
Rake the lower three to four feet of your roof immediately after a snowfall with a lightweight roof rake when, the snow is still soft.
Melt the ice dam with socks or pantyhose filled with calcium chloride socks. By pouring calcium chloride into this tube-like form, you can position it vertically over the dam—with the sock’s end hanging an inch or two over the roof edge—and melt a tube-like channel through the ice dam, which will allow additional water that melts to run safely off the roof. (DO NOT use rock salt, as that will damage gutters, siding, and vegetation below).
Call a professional – it may get expensive, but it may be warranted if the damage is extensive enough.
Obviously, it is cheaper and damage less extensive if steps are taken to prevent ice dams from happening in the first place.