 What are ice dams?
Ice dams are a buildup of ice and water caused by snow on rooftops. As the snow melts, it slides to the edges where it refreezes, creating an ice dam. Eventually, the ice builds up and blocks water from draining off of the roof. This, in turn, forces the water under the roof covering and into your attic or down the inside walls of your house.
How are ice dams formed?
- Frozen or clogged gutters
- Dark shingles that absorb heat
- A low roof pitch
- Heat loss from your home. This is the most common cause. As your unheated attic is warmed (see below), snow melts and begins to flow. The water flows to colder areas and freezes, creating an ice dam.
What damage can ice dams do?- Lifting of shingles
- Stained ceilings in interior rooms
- Damaged insulation
- Peeling paint, both interior and exterior
- Damage to exterior walls
How do you prevent ice dams?- Identify and seal leaks from your attic to your interior rooms.
- Keep gutters free of leaves, branches and other debris.
- Have snow removed from around gutters and eaves.
- Increase ceiling or roof insulation.
- Make sure an unheated attic is well vented.
- Have rubber applied under shingles if you’re replacing a roof or building a home.
- Eliminate recessed light fixtures near the roof.
Where do you locate air leaks?
- Check around electrical fixtures, wiring penetrations, kitchen and bath exhaust fans, at the tops of interior walls and dropped ceilings, at the entry to the attic and where the chimney and stack enter the attic - all are common places for leaks.
- In your attic, look for signs of air leakage from below: wet or dirty insulation, dust buildup or water staining under insulation, frost buildup on roofing nails.
How do you seal the leaks you find? - Use pieces of insulation batting for around electrical wiring and around electrical outlet boxes.
- For small gaps and holes at the top of interior walls, try a flexible caulking.
- For larger gaps, use expanding foam sealant, strips of wood or plaster board.
- To seal leaks around the chimney and stack, you may want to consider hiring an insulation specialist, as sealing these requires extra care and much more detail.
Freezing Pipes
Frozen water in pipes can cause water pressure buildup between the ice blockage and the closed faucet at the end of a pipe, which leads to pipes bursting at their weakest point. Pipes in attics, crawl spaces and outside walls are particularly vulnerable to freezing in extremely cold weather, where holes in your house’s outside wall for television, cable or telephone lines allow cold air to reach them.
To keep water in pipes from freezing, take the following steps:
- Fit exposed pipes with insulation sleeves or wrapping to slow the heat transfer. The more insulation the better.
- Seal cracks and holes in outside walls and foundations near water pipes with caulking.
- Keep cabinet doors open during cold spells to allow warm air to circulate around pipes (particularly in bathroom(s) and the kitchen.)
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