Ice Dam Information
What is an Ice Dam?
Ice dams are formed by melting snow. When the warmth of a home melts snow on the roof, the runoff heads downhill. When the runoff moves past the edge of the walls of the house, it cools off and turns to ice. Over time, that ice builds up and forms a ridge at the edge of the roof known as an ice dam. As the warm house melts more snow, it forms a pool of water behind the ice dam. When this happens, the water backs up under the lower shingles and begins to leak into the house through the roof or roof trim.
If a snowstorm is followed by sub-zero temperatures, ice dams can form with as little as an inch of snow. Larger snowfalls and lower temperatures form ice dams more quickly.
What kind of damage does an Ice Dam do to a roof?
Obviously, water isn't supposed to leak into your house. Here's what can happen:
First, the insulation in your roof gets wet. This makes it less effective at trapping heat, raising your heating and cooling bill. Less efficient insulation makes the formation of new ice dams more likely. Water can also leak into your walls, wetting both the insulation and the drywall. When wall insulation gets wet, it tends to sag and hang down, leaving the upper part of the wall un-insulated. This will also increase the energy necessary to heat and cool your home, costing you more money each month. The peeling paint, stained ceilings, and damaged wallboard is easy to spot, but other damage often goes unnoticed. When moisture gets trapped in the cavity between the exterior wall's plywood and its interior vapor barrier, the result can be a smelly, rotting wall. Wall studs can decay and metal connecting parts can corrode, compromising your home's structural integrity.
What else can Ice Dams do?
Ice dams can also affect your own health. Moisture trapped in your walls help mold and mildew to grow, making your home a danger...especially to allergen-sensitive visitors and family members.
