Perhaps you saw them around the holidays: white or blue outdoor lights that simulate trickling icicles. Or greeting cards that depict houses with large icicles hanging from the gutters. While the frosty stalactites may look pretty, they may actually be a signal of trouble in your own home.
Icicles are commonly thought to be a sign of an ice dam on your roof, but are they? Possibly, says Rem Brown, senior engineering manager at the Insurance Institute for Business and Home Safety (IBHS).
The three things necessary to form icicles — snow, heat to melt the snow, and cold weather — are also necessary to form ice dams, he explains. Ice dams form when warm air from inside your home melts snow on the roof. When the meltwater reaches the colder eaves (the part of the roof that extends beyond the walls), the water re-freezes and creates a buildup of ice along the edge of your roofline.
So, icicles hanging from the roof edge could be a sign of an ice dam (and larger icicles would likely indicate a larger ice dam, Brown says), but ice dams can even form without the presence of any large icicles.
The more snow and ice accumulate, and temperatures rise and fall, the larger the potential for ice dams. And ice dams can wreak havoc. They can damage and loosen shingles, rip off gutters and may cause meltwater to pool and seep into your attic, says the IBHS. Once that happens, insulation can get wet, paint can peel and the structure of your home can become damp. Untreated, this may cause rotting wood, damaged drywall and even mold growth.
It’s best to remove snow from a heavy snowfall immediately to help prevent the buildup of ice dams later. Though you might hear about people doing anything from using a snow blower to remove snow or an axe to help chip away at an already-formed ice dam, both methods may damage your roof, the IBHS warns.
A push broom with stiff bristles can be used to help remove snow off flat and low-slope roofs, while a roof rake can be the right option for sloped roofs, the IBHS says, because you can remain on the ground and still remove snow. Of course, if you’re unable to easily reach the roof, or just unsure about your ability to do so, ask a roofing professional to do the job.
In the event that an ice dam does form, the IBHS suggests keeping the attic well ventilated — the colder the attic, the less melting and refreezing on your roof, the IBHS says.
According to This Old House, the best way to help prevent ice dams is to keep your roof and eaves the same temperature. Here’s how:
Preventive steps like these can help preserve the health of your home by eliminating ice dams — and maybe even those icicles!