This is especially important because ice dams are often pushed by roofing companies as another one of those “options you may want to have or else…” Since it is natural to be suspicious of roofing companies offering options, the instinct is to turn it down. But this may not be a wise choice. Let's look at what can happen when an ice dam forms.
How Ice Dams Can Ruin Your House
- Snow Falls. First, of course, the snow falls. It doesn’t have to be giant snowpack, either. Snow in any quantity can result in an ice dam.
- Snow Melts. After snow falls on a roof, it will eventually (we hope at least) start to melt. Snow on a roof can melt quite rapidly, due to its high exposure to the sun and also due to heat rising up through the house. Homes with poor insulation are more susceptible to ice dams, because more heat escapes through the roof.
- Snowmelt Drains. The liquid snowmelt flows downward until it reaches the eaves or the gutter. But the eaves or gutter (we bring up both of these because you may not necessarily have a gutter, but all houses will have eaves) do not warm up like the upper regions of the roof do. The eaves and gutters remain quite cold, meaning that ice builds up. It becomes a cyclical process. The snowmelt flows down, reaches the ice, and turns into more ice.
- Ice Dam Results. Eventually, you have a quite sizable dam of ice along the edges of your roof.
- Water Seeps Between Shingles. So what's the big deal? The snowmelt is going to keep coming down and backing up behind the dam. Then, that backed-up water has the luxury of time to seep under the shingles. After the water seeps between the shingles, it flows into the ceiling and and into your house. Now that is a very big deal.
When roofing companies install ice dam protection, they run a strip of rubber flashing all around the perimeter of the roof before laying down the shingles. No, it does not prevent the ice dam. It merely helps to prevent seepage from the ice dam.
Ice dams are quite a serious problem. Even if the water does not reach the stage of flowing through your ceiling and into your house, it will probably cause moisture in the attic which will then result in mold.