How to Avoid Ice Dams on Roofs
Those icicles dangling from your gutters may look pretty, but a closer look may reveal a bigger problem â€“ ice dams.
Ice dams build up when snow melts on the roof, causing water to run down and refreeze at the roofâ€™s edge where temperatures are much lower. The icicles or ice sheets block melting snow, causing it to back up under shingles. From there, the melting water flows inside your house and down walls, or seeps through the ceiling.
Costly hidden damages
Besides the obvious water-stained ceilings, damaged roof shingles, sagging gutters and peeling paint, ice dams can cause some hidden problems. For example, insulation loses its effectiveness when itâ€™s wet, and because itâ€™s been flattened by water, it doesnâ€™t work as well even after it dries out. Itâ€™s the start of a vicious cycle. The damaged insulation means more heat is lost, which leads to more ice dams. Plus, youâ€™ll see your heating bills rise.
And thatâ€™s not all. Your walls and ceiling can rot from the inside, leaving unpleasant odors, as well as mold and mildew â€“ real health concerns â€“ which can compromise the structural integrity of walls and ceilings.
Prevention Tips: ventilate and insulate
- Keep your attic well-ventilated to outside air.
- Add additional soffit venting.
- Make sure your attic floor has adequate insulation to minimize the amount of heat escaping into the attic from the house. (This is a win-win solution, because it can lower heating costs, too.)
- Block any gaps around pipes that can cause warm air to escape to your attic.
- Install an ice-dam protection sheet, a rubber membrane that sticks on the wood under the shingles. This can help on a south-facing roof where thereâ€™s consistent melting.
- Remove the snow from the bottom seven to eight feet of the roof. This clears the way for the melted snow to reach the gutters and drain to the ground. But be safe: Keep your feet on the ground while using an extendable roof rake, and be careful not to come in contact with overhanging wires.