Bob, who seemed like a perfectly reasonable guy when I met him, is taking a hatchet to our porch roof. Soon, he'll start hacking away at the third floor roof. With any luck, once he's done, water will stop stretching its dark pointy fingers across my bedroom floor, and the unseemly discoloration of our living room ceiling will become just a hint of a shadow. As for the brownish stream running down the window seams like a persistent bloody nose? I'm hoping that'll go away, too. Bob says the water is brown because the ice dam on our roof melted a bit and the water picked up color from tannins in the wood on the way down. I promise you I have other thoughts about how that water got brown.Bob is a professional roofer. He estimates that 10 to 20% of houses in Toronto are dealing with roof ice dams and ice damming consequences right now. I imagine that's a bit of a boon for an industry that doesn't have that much to do in the thick of winter, but to be frank I don't take much comfort in that. For homeowners, roof ice dams rot. Now that I know a thing or two about them, you guessed it, I'm going to share.
First, know this: Your children are wrong. Icicles hanging off your roof are not pretty. (Nor are they a recommended part of a balanced diet). Next time you see a theatrical curtain of glass daggers dangling from your roof, think "Woooop woooop warning!" Icicles indicate that your roof is warm. That's fine, so long as the source of heat is the sun. Chances are, however, that heat is rising from inside, causing snow to soften, melt, slide down and freeze at the magic edge - where the temperature drops to 32 degrees. Over time, as more snow comes and melts, that ice pack from the edge backs up, slides under your shingles and comes inside. And that, my friends, is just no fun.
So what can you do? In the short term, get the snow off. Borrow a roof rake from your neighbors and remove snow from your roof. No snow, no ice dams. That said, be careful not to damage your roof with your eager scraping. Some people have had success making channels for the water, by getting warmer water to create flow - be warned, however, that this is very temporary. In the long term, insulation is the answer. Stop sending heat through the roof - literally.
The amount of insulation you need depends on the snowfall and the climate, but it is recommended that a minimum of R30 should be provided below ventilated attic roof membranes, R35 below ventilated cathedral ceilings, and R40 below unventilated cathedral ceilings. These insulation levels should be increased for very cold climates (DOE Zone 6 or higher). For more details, check out the photos and graphics about ice dams put together by the good folks at Building Science Corporation.
Or, you could always move. I'm thinking Hawaii. Any takers?
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