Ice Dams
by Alex Wilson
If you mention ice dams around
here, most builders groan and nod,
with an I'm-all-too-familiar-with-thatproblem
look. The past two winters,
while great for the New England ski
industry, have been among the worst
in recent memory for ice dams.
In this column, I'll take a look at
the problem of ice dams: why they
occur, and how you can avoid them
(or at least reduce the potential
damage).
The Cause
Ice dams form when snow melts
on a building, allowing water to flow
down the roof surface and freeze at
the overhang. I've seen ice dams
more than a foot thick. The ice acts
as a dam, causing additional
snowmelt to back up the roof-as
much as