That dammed ice

Last week we had a quick ice storm come through, followed by about a foot of snow. In the area there have been a few roofs collapsing under the heavy snow and some businesses temporarily closed for fear of the same. On the north side of our roof we have two separate rooflines, and a large drift formed on the lower one against the upper one. I wasn’t too terribly worried about the weight of the snow, but I was worried about the many times the temperature has flucuated about the freezing point.

The problem when you have snow on the roof is that it can melt even when the outside temperatures are below freezing, since the air in the attic can be warmer due to heat leaking from the house. The water then runs down the roof until it gets over the eaves. In some cases, the roof is colder there than near the top and the water can freeze. If this happens enough, a dam of ice can build up near the edge of the roof. When this dam forms, melt water backs up and can get into your roof by going up under the shingles (shingles basically only work for water heading downwards).

Well, it appeared that this was happening on our roof, so for the past several days I’ve been trying an array of crazy ideas trying to knock the snow off, from ropes strung over the roof to a rake on a 35ft pole (it’s a two-story roof). I’d searched online for ideas, and the basic advice was 1. use a roof rake, 2. call a professional and 3. don’t get on the roof.

So anyway, today I got up on the roof. I stayed on the south side of the roof, which due to the sun was completely clear of snow and ice. I carefully used my 35ft duct tape-assembled rake to push most of the snow down off of the roof and discovered there was quite a bit of ice underneath, and it was starting to form a dam. Since we’re expecting higher temperatures next week, I figured the dam had to go before it let all the melt water into the house. I drug a hose up onto the roof and cut a small channel through the ice with hot water, giving the melt water a way to get past the ice and to the ground. After quite some time on the roof with temperatures in the teens, lots of wind, and getting wet from my inability to properly hold a hose, a cup of hot tea and a blanket were a welcome site!

From what I read, the icicles are often a sign that you’re getting an ice dam. They also say that the best remedy is to add some insulation to your attic, basically keeping all the heat inside the house, so that the attic is no warmer than the outside air.