To Ohio homeowners in snowy, cold-winter climates, ice dams are a familiar sight. An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow (water) from draining off the roof. The water that backs up behind the ice dam can leak into your home and cause structural damage to walls, ceilings, insulation, and other areas.
Ice dams can be prevented by controlling the heat loss from the home. Remove snow from the roof. This eliminates one of the ingredients necessary for the formation of an ice dam. But, don’t knock large icicles off your gutters. Be aware they may be a sign of ice dams forming. You could wind up injuring yourself – falling chunks of ice are unpredictable – or damaging to your home. Leave them be, but keep an eye on them.
Preventing ice dams is a matter of simple thermal physics. If the air in the attic or against the bottom of the roof deck remains cold, it can never melt the snow lying on top of the roof, eliminating the water necessary for ice dams. Preventing ice dams can be done through a combination of:
- Ventilation under the roof deck, which keeps colder outside air circulating through the attic and prevents it from warming above the freezing point so it can melt snow on the roof.
- Insulation in the ceiling below the attic, which will prevent warm air from rising up into the attic space to melt snow on the roof.
- Blocking any heat sources that may be contributing to high temperatures in the attic.