Let it snow: Roofs can take the weight

January 02, 1998|By Boston Globe

Snow and ice raise havoc with houses -- or at least people

think they do.

So, what to do: Shovel? Heat the attic? Make the attic cold? Insulate? Ventilate? Not necessarily any of those.

It's a safe bet that 99 percent of houses in the North will hold more snow than Old Man Winter can throw at them -- several feet worth, in fact. They're built with snow in mind, and their roofs are steep enough to hold heavy weights or to allow snow to slide off. Even a fairly gentle slope will handle snow. Here's why:

Roofs already hold the weight of asphalt shingles or slate, which can weigh up to 30-plus pounds per square foot. And many hold two layers.

Snow weighs about 5 pounds per square foot, 12 inches deep, depending on water content. About 12 inches of snow equal 1 inch of rain; a cubic foot of water weighs 62.4 pounds; divide by 12 (1 inch) and you get a shade over 5 pounds per square foot of rain, 1 inch deep.

Five pounds per square foot is hardly anything added to a roof, considering what is already on it.

Pub Date: 1/02/98

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