By Mike McClintock Special to Tribune Newspapers
February 14, 2013
Even in a nearly snowless winter, it pays to think about what a big snow does to the roof over your head, so that you're prepared when snow comes calling, or can build cold weather preparations into this spring's renovation. A big snowfall will stay on the roof of a well-insulated house until the sun melts it or the wind blows it away — one reason rafters are designed to carry a lot more than shingles. You could wait for a warm day and hope the melt doesn't freeze into ice dams along the eaves. Or you could try a snow-removal home improvement. They include some ingenious schemes and unusual tools.
The old-fashioned approach is to line the eaves with sheet metal. The metal's top edge tucks under the roof shingles and its bottom edge empties into the gutter. The idea is to make snow and ice slide off the roof — at least along the edge — because sheet metal is so much slicker than the granular coating on shingles.
The more modern approach is to install a heating system — heat cable that loops along the overhang to melt snow and ice that accumulates. It's a reliable way to prevent ice dams at the eaves, and also buildups in valleys and around dormers. The cable is easy to install with clips that attach to shingles. Because it's outside and wet, the grounded system requires an exterior-rated outlet protected by a GFCI breaker.
Many heat cable companies also make sensors to trigger the melting automatically.
Snow rakes have a scoop-shaped shovel at the end of a very long pole so you can clear at least the eaves working from the ground. Over 15 to 20 feet long they become unwieldy for most people, though for two-story homes some have handles of up to 36 feet long. The idea is to raise the shovel end, balance it, move toward the building, drop it as far up the roof as possible, then pull.
Among many shapes, sizes and brands, I've had good results with the Ames Telescoping Roof Rake (details on the Web at amestruetemper.com, about $55).
Snow razors use a different approach. The gawky looking tools also have very long handles so you can work from the ground. But you start the business end at the roof edge and work up. At the front, two small wheels support a thin bar that slices under the snowpack as you push the tool up the roof. A rolled-out plastic slide trails behind. As sections of snow are cut loose, gravity sends them down the slippery slide and off the roof. One popular model is the Minnsnowta Roof Razor, available at 24 inches wide for $130 and 36 inches wide for $155. See details at minnsnowta.com.
Should all else fail, the best backup protection against leaks from ice dams is a self-sealing underlayment. Unfortunately, on an existing roof you have to remove shingles along the overhang to install it.
Grace, Certainteed and others make similar products called ice and water shield membranes. The thin, rubbery mat rolls out with no seams and has adhesive on the bottom that sticks to the plywood roof deck. When shingles are nailed on top of it, the material seals around the punctures. Then, if water backs up under shingles it flows down the rubber shield to the gutter.