5 Ways to Prevent Ice Dams

December 12, 2007


Ice dams are nasty, ugly, destructive things. Here in the Northeast, where the temperature can be below zero one day and 40 degrees the next, ice dams are a loathesome reality. We recently took a trip out to Hamilton College, and I saw with some dismay that large icicles loomed off the roofs of those beautiful stone buildings.

I’ve read many things about ice dams over the years. Thank God we’ve never had a very bad time with them at our present house (although previous owners did, judging by the scars in the plaster). An apartment we lived in a few years ago suffered an ice dam “attack.” The damage was done to our upstairs bedroom. Everything– the carpet, anything on the carpet (the bed, the dressers, the boxes) were completely soaked. Not pretty.

I’ve done some research and have come up with a handy-dandy list of 5 ways to prevent ice dams. Of course, if an ice dam is bound and determined to attack your home, there isn’t a whole lot you can do. (In other words, you’re still at the whim of the weather extremes and severities). But this can help. All these tips are really wrapped up in four simple words:

Keep your roof cold.

Ice dams form on the roof when there is a cycle of warm/cold/warm/cold. The snow on the roof melts and refreezes. The ice builds and creeps up into the shingles or underneath gutter supports, If allowed to continue, the ice will build up into the interior wall, where it will melt. This was what happened to our soggy apartment that one year.

1. Insulate your attic floor. But do not insulate the soffits! You must have cold air flowing up along the underside of your roof. Continuous soffit vents (and a ridge vent at the exterior top peak of your roof) keep cold air circulating. Insulating the attic floor will keep the heat down in the living spaces of your home and out of your attic. The big thing is ventilation. A cold attic and a cold roof doesn’t produce enough heat to melt that snow on your roof; thus, no ice, and no ice dam.

2. Seal any and all gaps, holes, and cracks. You want to keep heat from escaping your living spaces. You don’t want heat leaking into the insides of your walls, up your eaves, or into your attic.

3. Remove gutters. (or, remove them just for the winter) This is a touchy issue. My house has no gutters and I hate it. The land around the house is pretty soggy. I now know why all those old houses had big, wrap-around porches. Not only did it make a cozy place for Grandma to shell peas, but it protected the foundation from water from the roof.

Gutters trap water, and water in the winter freezes. If the ice in the gutters builds up, the ice will eventually make it way up the roof and under the shingles. We have a small section of gutter across our front porch. Every year it fills with ice, every year the ice builds up, and every year we have a huge ice dam. When the gutter fell down this spring, we have never bothered to put it back up.

4. Install flashing around your chimney, and install a boot around any vent pipes coming through the roof. If the flashing or boot is old and corrupted, replace the whole thing. Patches don’t last very long, and you don’t want to be up on the roof constantly fixing patches, do you?

5. Add a turbine to your roof. This is no quick fix, obviously. My neighbor has a few turbines on his roof and they work wonderfully. He hardly has any icicles on his eaves. The turbine acts as a vacuum by spinning with the air flow and sucking air out of your attic to the outdoors. It is an excellent, passive way of keeping the air in your attic circulated.

Those are just five quickie tips. I didn’t add the popular heat cables to my list. I’m not too fond of them, actually, especially when there are better, more energy-efficient means.

Do you have an ice dam and need an emergency fix? Here’s a few tips I’ve come across: turn on a fan in your attic and point it at the suffering area. Cooling the air in the attic will stop the leaking very quickly.

Also, I’d read that a pantyhose leg stuffed with calcium chloride and tossed onto your roof will melt the ice. The hose will create a channel for melting water to follow. Interesting! I’ll have to keep that in mind should we ever get afflicted. I’ll also have to buy some pantyhose to have on hand…


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