Jay Romano wrote a great column in his New York Times home improvement series, “The Fix” last week addressing ice dam solutions. I think it only goes half way, though, since the article offers roof shoveling and heat tape as partial solutions. The truth is, only with a well-sealed and well-insulated attic can you reliably and permanently control the expensive damage wrought by ice dams and avoid unnecessarily high utility bills.
Here’s the thing about raking snow—it’s only potentially effective if you decide that you have an ice-damming problem the day of a big snowstorm. You can do it yourself by buying a snow rake, or hire someone to do it for you each time you get a snowfall. But do you really want to add shoveling the roof to your existing shoveling chores, or add to your current snow removal bills? And just shoveling the snow off the first two or three feet of the roof isn’t going to do it: the show further up the roof can melt down and create dams.
Ditto with heat tape, which not only costs $300-600 according to Mr. Romano, but must then be installed and can be very expensive to run. (Set an electric heater outside and then tell me about your electric bill!) Electric heat tape requires fasteners, which penetrate the shingles to hold it in place, and can damage shingles. And unfortunately, many people let heat tape run even when not needed – when there is no snow on the roof (or, yikes, all summer long!), for example – causing even higher bills.
The rigid foam method Tom Silva recommends, in which the attic is insulated all the way up to the peak, between the rafters, can work—but air sealing along with it is critical, and probably beyond what most homeowners can tackle solo. For twice the price of the materials, which are expensive in and of themselves, a homeowner could have closed cell polyurethane insulation installed (that is, with all labor included) to an equivalent depth, which will do the trick. But many homeowners don’t use the attic as living space. If you rarely venture up there, you can insulate just as well, if not better, for a fraction of the cost. A well-sealed and well-insulated flat attic, with good attic ventilation—of the kind we do every day—will outperform Mr. Silva’s approach. (Again—it depends on whether and how you’re using the attic—mine is conditioned living space so the flat attic treatment was out.)
Now, go outside, and take that heat tape off! (And then call someone to insulate and air-seal your attic!)
Stay warm,
Mike
