Removing An Ice Dam
Do You Have Ice Dam Problems?
If your home has a steep sloped roof, and is more than 20 years old, there is a high probability that your attic has excessive heat, leading to ice damming. I spent some time this weekend removing ice dams from my house. Here are some thoughts:
What Is An Ice Dam?
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. This water often backs up behind the dam causing leaks into a home and damaging walls, ceilings, insulation, and other areas.
Ice dams usually occur after a heavy snowfall followed by several days of freezing temperatures. An ice dam forms when warm air inside your home leaks into the attic and warms the underside of the roof causing snow and ice on the roof to melt and drain down to the roofs edge.
The melted roof water drains along the roof, under the snow, until it reaches the cold overhang. The overhang tends to be at the same temperature [below 32 degrees] as the outdoors and the melted water freezes at this location and builds up. Icicles are often an good indication that you have an ice dam.
What Causes Ice Dams?
The most likely causes of ice dams are due to heat loss, air leakage and the general warming of the house structure due to conduction from the heated building.
Ice dams are usually caused by heavy snowfall and improper ventilation, insulation and air leak sealing in the attic. This causes warmer areas in your attic then the snow begins to melt, even when the outside temperature is well below freezing.
When the accumulated snow on your roof starts melting it runs down your roof underneath the snow until it reaches the “colder” colder overhang. The overhang tends to be at the same temperature [below 32 degrees] as the outdoors and the melted water will refreeze and form an ice dam and icicles.
Other areas like the valleys or in gutters then it begins to freeze again, this process of thawing and refreezing is what causes an ice dam.
The photo above: [2nd story house with ladder and icicles] is my house. It was built in 1863 and renovated in 1993. This area of the roof has 2×10 rafters and fiberglass insulation with baffle “proper” vents that travel, a long way in the rafter bays, to the ridge venting.
Insulation is minimal and air leak sealing was not done well. At that time I did not know a lot about ventilation and installed a Hix Vent which is now covered in ice. Currently there is no access to address insulation but I can do one thing to improve these conditions. When re-roofing I added a continuous sofit vent to improve ventilation.
Dealing With Ice Dams:
Tools and Materials Needed:
- Ladder with stabilizer bar [rope / eyehook]
- Ice Pick, Large chisel or hammer claw
- Snow rake
Read more to see how to Remove an Ice Dam – next page