Looks like time to re-post this classic, after all: Last year, half the houses in the neighborhood developed ice dams. Part of the reason? This neighborhood has tons of bungalows.
The bungalow is native to sunny India, where the deep overhang of the eave acts like an awning.
Maine and India have little in common beyond the bungalow. Here, that overhang gets very cold, because it’s not heated by warm air rushing upward through the ceiling and into the attic.
That fleeing warm air does heat the roof over the attic, however, and melts the snow thereon. Water runs down the roof as god intended. But then it hits the unheated overhang and promptly freezes. Over time, a ridge of ice forms atop the eave. Now running water backs up behind a growing ridge of ice, seeps between the shingles, and enters parts of your house previously reserved for dryness.
The slanted ceiling of a bungalow’s second floor makes matters worse: You can’t add much insulation there to slow the flow of heat.
The outdoor angles compound the problem, as intersecting roof lines direct a lot of water toward the valleys.
What to do? Don’t do this: In a fit of freezing pique I once took a pickax to my ice dams. It tore that ice right up! And the roof under it, too!
Prevention, as usual, is the sensible thing. Maintain a clear path for water to take off the roof. Rake snow off the eaves before the cycle sets in.
And if you must build a bungalow in Maine, insulate the heck out of it.