Why Does My Roof Leak When it Snows?

Cause

• Ice dams occur during freezing weather when the temperature on the top of the roof stays warmer than 32 degrees Fahrenheit, while the temperature on the bottom of the roof stays below freezing. The snow on the top portion of the roof melts and drips downward. However, the water turns to ice when it reaches the bottom of the roof and forms a dam. Water builds up behind the dam and starts leaking into the house.

Heat Source

• For an ice dam to form, a heat source must warm the higher potions of the roof when temperatures average below 32 degrees for extended periods. Warm air often rises through the living spaces of the house and collects in the highest reaches of the attic. Chimneys also play a role in heating the roof, as heat from the flue can warm the attic. Bathroom and kitchens create roof warming by allowing heated air an easy route to the top of the house.

Prevention

• Proper insulation remains one of the most effective preventative measures against ice dams, according to the University of Massachusetts. The university recommends using 12-inch deep fiberglass or cellulose insulation to adequately combat heat escaping from the home's living spaces to the attic. Any airways letting heat through to the attic, such as light fixtures and holes for wires or plumbing pipes, need caulking and sealing to prevent heat loss.

Safety

• Perform any actions taken to rectify an ice dam on your roof with safety as your priority. The roof conditions during times of snow and ice formation can easily lead to serious injury. If you want to remove snow from your roof, use a snow rake. Avoid going onto the roof surface itself, advises the University of Minnesota. Hire professionals to limit any risk of bodily harm to yourself or damage to the roof.