Roof Ice Dams, Damned Nuisance, Must Be Addressed


By Bill Primavera

The Home Guru


When I moved from the city to a home in the suburbs, I really enjoyed our first winter of heavy snow. I remember that when I build a snow man 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 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 F, 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 happens there is little that can be done for an immediate remedy. Trying to break the ice dam 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. That suicidal I’m not.

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

On many homes 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 and, at less than $1.00 a linear foot, make a cheap and quick fix. But that doesn’t fix the problem long term.

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/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 home, you’re probably the beneficiary of state codes for proper ceiling/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. But, 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 licensed Realtor® (, affiliated with Coldwell Banker, and a marketing practitioner ( Anyone considering selling or buying a home can reach him directly at 914-522-2076.