Ice dams form when water freezes on a cold spot on a roof, usually at the eaves. Water that pools behind the ice dam can eventually work its way through the roof covering into the home. Three conditions must be present for an ice dam to form: snow on the roof, heat to melt the snow and cold to re-freeze the melted snow With ice accumulation, the dam retains enough melted water behind it to allow the water to work its way under the roof covering, resulting in water entering the structure. Water can then make its way to the ceiling and/or run down the walls.
- Seal warm air leaks from interior rooms to the attic. (This will also cut your heating bills.)
- Ensure that you have adequate insulation in the attic. Homes in the northern U. S. should have at least R 38 (about 12 inches of fiberglass or cellulose) above the ceiling.
- Be sure there is unrestricted air movement under the roof from the eaves soffit to the ridge.
- Clean the roof gutters in the fall after the foliage has fallen. Though clogged gutters do not create ice dams, they can cause ice to back up onto the roof.
Remove all of the snow from the roof. This can be accomplished by shoveling, or by reaching up from the ground with a long-handled rake. Use caution so that you don't fall off the roof when shoveling, or get hit with a chunk of ice if you are raking the snow off the roof. Structural damage can occur when the weight of snow and ice exceeds the load-bearing capacity of your roof. This is most often the case with flat roofs, older buildings, or structures whose integrity may already be compromised.
- Generally, if there is more than a foot of heavy, wet snow and ice on your roof, you should try to have it removed.
- If you have a flat roof that is easily reached from an interior stairway, you may want to shovel the roof. Remember to put safety first any time you are on a roof. If you have a sloped roof, it may be possible to remove the snow and ice using a roof rake, a long-handled tool designed specifically for this purpose. Stand on the ground and pull as much of the snow off the eaves as you can safely reach. It is not necessary to remove all the snow; removing the first three to four feet of snow closest to the gutters will help alleviate these issues. Do not use a ladder in snowy and icy conditions.
- Many homebuilders, landscaping and roofing contractors, and property maintenance companies will remove snow and ice from roofs. Before hiring a contractor, check references. Always be sure your contractor is insured and bonded.