Ice dams are not a creation of winter beavers. That would be a much nicer situation.
We had some water dripping into our kitchen a few weeks ago. I thought that the cats had spilled something over night. They hadn't. No beavers either.
Ice dams form when the temperature roof over the attic is raised by warm air leaking into the attic. This melts the snow that is in contact with this part of the roof. This water flows down to the eves and/or gutters. The water freezes here as the eves aren't warmed by the attic. This forms the ice dam and as more water flows down it leaks into the roof and in our case inside the walls.
Most of the water has frozen there, but this is the first time there was enough to leak into the house. We have apparently had this issue for as long as we've lived here. It is only happening on the back of our house. This part of the house faces east and doesn't get much sun this time of year.
We will have to wait until the spring before we can do anything to prevent this form happening again. There are 2 things we can do.
- Insulate and ventilate the attic. Keeping the warm air from getting to the attic will prevent the snow from melting. Increasing the attic ventilation will also help to keep the temperature of the roof the same as the outside air an preventing the snow from melting.
- Melt the ice dam when it forms. You can buy heating cable that is designed to be strung on the shingles on the eves. This also prevents the ice dams from forming. I've seen this on some of our neighbours roofs, but didn't know what it was.
