Severe winter weather can present a lot of challenges for homeowners, and ice dams are among the most serious problems that can arise. Ice dams – solid walls of ice that prevent runoff and cause roof leaks – occur when snow melts from the upper part of your roof and then refreezes around your gutters. As with many winter problems, prevention is a far better course that trying to deal with an ice dam once it forms.
Causes and Symptoms
An ice dam can form when heat leaking out through your ceiling causes the temperature at the peak of your roof to climb above freezing, while the lower part of your roof stays cold. The runoff from melting snow trickles down until it freezes again, creating a solid barrier of ice. The ice dam blocks further runoff, which pools in a reservoir behind the dam and eventually starts leaking through. Ice dams are often visible from the ground, and can sometimes be given away by excessive icicle formation. Water stains and leaks will often be visible in your attic.
Many homeowners attempt to prevent ice dams by keeping their roof warm, but in fact the opposite course is more effective. You want the outer surface of your roof to remain uniformly cold on sub-freezing days to prevent snow melt. There are a few ways to prevent the formation of ice dams, the most effective of which is to make sure your attic and roof are well-insulated to prevent heat from leaking through. Sealing air leaks with caulk, weather stripping and spray foam is also helpful, and proper attic ventilation can help direct warm air away from your roof. You should also try to keep your gutters clear to allow runoff to drain away as quickly as possible before freezing.
Dealing with Ice Dams
Once an ice dam forms, it can be very difficult to deal with. Climbing ladders and walking on your roof in cold, icy conditions is an extremely dangerous undertaking, and trying to break away the ice can cause further damage to your roof. Waiting until a day when temperatures are above freezing and spraying the ice dam with warm water can help it to break away faster. Barring this possibility, the best thing to do once an ice dam forms is to contact a roofing professional who can assess the damage and fix the problem if possible.