Home Guru: A Damned Nuisance: Roof Ice Dams Must Be Considered

By Bill Primavera

Having just arranged to have my gutters cleaned of the leaves that accumulated there during the fall, I am reminded of another issue concerning a house’s roof care that is of utmost importance in snow season: the prospect of ice dams.

When I moved from the city, I really enjoyed our first winter of heavy snow. I remembered that when I built a snowman for my four-year old daughter, it stayed clean, fresh and white, rather than being speckled with black soot like the one I had built the year before in Brooklyn.

I also remember looking up at the roof line on the northern side of my house and admiring the icicles hanging from the fascia and gutters, thinking that they added interest to the wintry scene, much like a perfect 19^th century Currier and Ives print.

Little did I know, naïve as I was as a homeowner at that time, that icicles were a byproduct of an ice dam, that winter roof phenomenon that can cause leakage into the house, damaging insulation, ceilings and walls. And that’s exactly what happened to me in a year full of surprises as the new owner of an antique house.

I’ve since learned that ice dams form in a complex interaction resulting from heat loss from a house, snow cover and outside temperature. What happens is that snow on the upper part of the roof, where the temperature might be above 32 degrees, melts and flows down to the lower part of the roof where the temperature might be below 32 degrees, and there it freezes to form the ice dam.

The dam continues to grow while the water trapped behind it finds cracks and openings in the exterior roof covering, dripping into the attic space and, from there, flowing into the exterior walls and ceiling. It can be a mess.

The solution is complicated because a number of factors can contribute to the possibility of ice dams, including exhaust systems that come from our bathrooms and kitchens, recessed lights, skylights, complicated roof designs and heating ducts in the attic.

Once an ice dam forms there is little that can be done for an immediate remedy. Trying to break it physically can do more damage than the dam itself. That first year one well-meaning neighbor suggested that next time it snowed, I should physically remove the snow from the north side of my roof with a roof rake and push broom. Sure thing, I thought, all I have to do is climb on the roof when it’s snowing. Suicidal I’m not.

Another possibility is to make channels through the dam where water can run through them to the ground. But that too can be a dangerous proposition.

On many houses you see electric cables along the ridge of the roof and, while some roofers say they may be dangerous if the wires wear thin, several homeowners who have them have told me that they work fine. At less than $1 per linear foot, it makes a cheap and quick fix. But that doesn’t fix the problem.

If you have the problem, the best long-term action is to call in a contractor who should check to see that your ceiling is air tight so that no warm, moist air can flow from the house into the attic space. After that, it can help to increase the ceiling and roof insulation to cut down on heat loss by conduction. That’s what I did and it worked.

If you live in a relatively new house, you’re probably the beneficiary of state codes for proper ceiling and roof insulation levels that all but eliminate the possibility of an ice dam. Or, if you live in a house with a high-pitched roof, the problem is less likely to occur.

But if you are a homeowner with a lower pitched roof and you see that ominous build-up of ice and icicles, call in a contractor to assess the situation and address it.

In the meantime, if you experience leakage from an ice dam into your house this winter, wait until the ceiling and walls have totally dried out before you attempt any repair work. More importantly, interior repair should be done in concert with correcting the heat loss problem that created the ice dam in the first place or the damage will occur again.

Bill Primavera is a Realtor® associated with William Raveis Real Estate and Founder of Primavera Public Relations, Inc. (www.PrimaveraPR.com). His real estate site is www.PrimaveraRealEstate.com, and his blog is www.TheHomeGuru.com. To engage the services of The Home Guru to market your home for sale, call 914-522-2076.