What causes ice dams?
An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow from draining off. The water that backs up behind the dam can leak into a home and cause damage to walls, ceiling insulation, and other parts of the house.
An ice dam might form when…
- There is snow on the roof
- Average outside temperature is below 32°
- Roof surface temperature is above 32° at it’s higher end and below 32° at it’s lower end.
How it forms
- Indoor heating rises through the ceiling into the attic and warms the roof surface
- Snow on the heated part of the roof melts and flows down until it reaches that part of the roof that is below 32°. Water freezes into an ice dam.
- The dam grows as it is fed by melting snow above, but the water held by the dam backs up and stays liquid.
- Eventually, the water finds cracks in the roof covering and flows into the attic from where it could seep through the ceiling and interior walls.
A Simple Solution
To Avoid Costly Ice Dams
