On the roof, it’s peaceful as can be . . .
James Taylor never experienced ice dams. Through the years I’ve become an expert on these frustrating winter constructions. For the uninitiated, ice dams occur when the snow on your roof melts from the bottom due to the space beneath your roof being warmer than the outside air. The water that results from the melted snow rolls down the shingles until it hits the part of the roof that extends over the soffet. (The soffet is the overhang that juts out from the exterior wall of your house). Because the soffet is extended over the outside air, it’s cold. When the melted snow hits that part of the roof it freezes, with some cascading over the edge to form ever lengthening icicles. The frozen ridge of ice at the edge of the roof creates a literal dam, blocking the path off the roof for the rest of the melting snow. This causes the dam to get higher and wider. Pretty soon, the melted snow starts backing up over the warm part of the roof where it works its way beneath the shingles and into your house. It often starts as a drip, drip, drip from a ceiling light fixture or a big wet spot on you ceiling. It’s very annoying.
The immediate action for water coming in, once buckets are in place, is to open up a gap in the ice so the water can drain off. If the roof is above the first floor, it’s best to hire someone to do this for you. There usually they’ll take a hammer and hack away at the ice until it chips off. Another approach is to dump chemical snow melt along the edge of the roof and let it do its work. You can fill up a tube sock with the stuff and leave it laying across the ice where it will melt a channel through it.
Removing the snow from your roof will solve the problem, at least until the next snow storm. With no snow to melt, there will be no water backup. I’ve used “snow rakes” before – they’re the long-handled contraptions with a blade at the end, designed to allow you to stand on the ground and pull snow off. I’ve found that removing only a few feet of snow from the edge only pushes the ice dam further up the roof, so in my experience, it’s all or nothing.
There are several long term solutions. Heated wires that you place in a zigzag pattern along the edge of the roof and plug into an outside outlet as needed have worked pretty well for me. They’re easy to install and keep channels through the ice open for water to drain. If you’re replacing your roof, consider installing ice/water shield, a rubberized coating that usually is placed on three feet along the edge, over the entire roof. The experts will say ensure your attic is well insulated and well ventilated so that it’s temperature will remain the same as the outside air and stop melting the roof snow from below. I think if you had a warm roof to begin with, you’ll always have a warm roof.
It’s frustrating. The only real solution is spring. Until then, we can always listen to JT.