Kimberly Van Hal, REALTOR
With Spring Temps on the Horizon, Watch for Ice Dams
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 your roof. The ridge of ice forms an ice dam where pooling water has no way to drain. Eventually, this water behind the ice dam will leak into the house and damage framing, insulation, sheetrock, walls, and perhaps electrical. The longer the ice dam exists the larger it becomes and the higher the chances are that the water will find its way into the house, which is why it's important to have ice dams removed early.
When Do Ice Dams Form?
There is snow on your roof,
It's below 32 degrees F,
The roof surface temperature is above 32 degrees F and the lower part (eave) of your roof is below 32 degrees F
How DO Ice Dams Form?
Heat from the house rises and warms the roof to above 32 degrees F
Snow on the warmer parts of your roof melts, turns to water, and flows down the roof to the eave.
When the water reaches a part of the roof that is below 32 degrees (normally the eave), it will freeze. Eventually, this forms a ridge or shelf of ice. It's called an Ice Dam.
The Ice Dam builds over time and creates a wall allowing pooling water to accumulate above or behind the ice dam.
This water build-up eventually can move back up your roof and leak into your home.
What to do if it happens
There is no fix for this condition other than to have the roof cleared of snow or wait for it to clear naturally. Most contractors do not clear roofs due to the VERY HIGH risk of death or injury to their roofing technicians by slipping and falling off the roof. Homeowners shouldn't go on the roofs themselves for the same reason.
What we suggest is that homeowners either let their roof clear naturally, with the understanding that water infiltration may occur until the roof is clear or hire a licensed and insured contractor that can clear the roof during the winter season. Once the roof is clear of ALL snow and packed ice, watch the areas that leaked through at least one heavy rain. If the leak doesn't reappear, then it was highly likely a one-time occurrence of ice damming.
NOTE: The roof must be clear of ALL snow and packed ice – even after the fluffy stuff is gone, there's often still packed ice on the roof.