Preventing Ice Dams on your Roof
For many people, there is something magical about icicles hanging from the eaves of a snow-covered house. But to those who know houses well, icicles are a sign that something bad might be going on under the roof.
The icicles, experts say, are a byproduct of an “ice dam,” a buildup of ice on the roof along the overhang, or eave — the part of the roof that extends beyond the exterior wall. The buildup is a result of energy loss from inside the house, which could cost a homeowner hundreds of dollars or more. It could also lead to problems like rotted roofs and rafters, ruined insulation, moisture inside the walls, mold, peeling paint and even physical injury from falling icicles.
Ice dams form when the upper part of the roof is warm enough to melt snow and the eaves are cold enough to freeze the runoff into icicles. What typically causes a roof to be warm is air from inside the house seeping into the attic and heating it up. When water from melting snow gets to the cold spot where the eaves begin, it re-freezes and creates a dam, and then a pool of water accumulates behind it.
Fast Fixes
Hacking away at ice dams with a hammer, chisel, or shovel is bad for your roofing—and dangerous for you. And throwing salt on them will do more to harm to your plantings than to the ice. Short of praying for warm weather, here are two stop-gap measures we recommend:
- •Blow in cold air: Take a box fan into the attic and aim it at the underside of the roof where water is actively leaking in. This targeted dose of cold air will freeze the water in its tracks.
- •Rake it: Pull off snow with a long-handled aluminum roof rake while you stand safely on the ground. A rake with wheels won't harm the roofing. But this deals with the problem in a one-time fashion.
- Another temporary solution is to install heat tape in a looping, wavelike pattern along the roof’s surface above the eaves. The tape, which warms up when plugged into the electrical system, creates channels in the ice to allow runoff, so water doesn’t accumulate on the roof. And the water that runs off is less likely to form icicles because it has been warmed by the heat tape.
- You can also install heat cables in the valleys of your roof to keep it heated and keep the icicles from freezing and becoming to large. This isn’t a cheap or fast fix, but in the long run will keep your roof safe from ice dams.
The absolute best way to keep ice dams from forming on your roof is to keep the snow off your roof to the best of your ability. After that huge storm hits, its in your best interest to get out there and clear that snow from your roof. Removing the snow will keep your house a warmer temperature and it should mean no more ice dams — and no more icicles.
