With the joys of winter comes a common source of frustration;
ice dams on our roofs that lead to water leakage, sometimes extensive
and damaging.
Ice dams are becoming a more common problem as we add more and
more insulation to our homes.
Why? Because the roof surface just above the eaves gets warm (the
heat is held in the insulation below that area), the bottom layers
of snow melt, the water runs down to the edge of the roof below,
freezing temperatures are encountered and ice forms. As this process
continues, a dam of ice forms.
Eventually, the dam extends far enough up of the roof that the
water behind it is kept warm by the roof and doesn't freeze. As more
water accumulates, it flows up under the shingles and leaks appear
inside your home, sometimes in very unusual places as the water follows
along framing members for great distances before appearing as a leak.
The key to correcting ice dam problems is proper ventilation. If
the roof surface can be kept cold, the process of ice dam formation
never gets started.
Now is the time to check your house for its ice dam potential.
Is there ventilation through the soffits?
Is the attic insulation stuffed tightly into the eave spaces and
against the underside of the roof?
Is there adequate year-round ventilation in the attic?
Are your gutters clean and in good condition?
If NO was your answer to any of these questions, ice dams are likely
in your home.
Before snow arrives, take time to improve the ventilation in the
attic and eave area of your home. You may avoid some expensive and
aggravating problems later on.
Wide metal flashing along the edge of your roof is another way
to minimize ice dams. However, this will not eliminate the cause
of the problem and can be easily damaged if you find reason to chip
ice off the roof in the winter.
Electrically operated heat tape is another defense against ice
dams. However, it is expensive to operate and can be a fire hazard
if improperly used or abused. And, again, it does nothing to deal
with the actual cause of the problem.
In the end, only keeping the roof surface cold with good ventilation
will assure minimum problems with ice dams and related water leakage.