Preventing Ice Dams

I received an email asking about
ice dams yesterday:

We have had our first ice dam,
causing some ceiling damage. We
have a snow rake on order; any
other ideas re: preventing another  
ice dam?

P.S. I am an old lady

We too have had ice dams at our
house. A temporary fix is to have
someone go up on a ladder and shovel
the show off the eaves and then throw
various ice melt products, such as
rock salt, on to the ice. This will
fix the problem temporarily so that
the roof no longer leaks for a day
or so. At least, that's my experience.

Of course, calcium chloride, another
form of salt, works much better than
rock salt. However, late in winter,
it becomes harder and harder to purchase
calcium chloride as the stores run out
of it. Also, it is much more expensive.

All of the above is a temporary fix.

For a more permanent fix, we hired my
first cousin, a building contractor,
to re-insulate our attic. This has
worked flawlessly and our heating bill
has gone down. This was done 2 or 3
years ago.

My cousin has 3 sons who help him work
on houses. Together, the father and
the 3 boys, put about a foot of insulation
in our attic. My cousin explored several
options and decided that blown-in insulation
would work best.

It has worked flawlessly! The house holds
heat very well now and there is no longer
enough heat rising from the house to the
roof to melt snow.

More insulation, in my view, is really and
truly the ideal solution. Over time, it is
a solution that pays for itself in lower heating
costs. It's ideal in another way too. It greatly
decreases the difference in temperature that would
naturally exist between the roof eaves and the
roof itself.

The ultimate cause of ice dams is heat rising
up from a heated home and melting snow on the
roof. If we did not heat our homes, we would
not have ice dams. Of course, no one is going
to stop heating their home.

Since no one wants to live in a cold house in
winter, the best alternative to a cold house is
to keep the attic well insulated. Attic insulation
is ceiling insulation. If you insulate your attic,
you are insulating your ceiling.

When you have adequate attic insulation, the
attic stays cold all winter and the snow above
the attic does not melt. Therefore, water does
not run down the roof at temperatures below 32
degrees Fahrenheit.

Keeping snow from melting at temperatures below
32 degrees Fahrenheit is the key to preventing
ice dams. If you allow water to run down the
roof at temperatures below 32 degrees Fahrenheit,
it tends to refreeze when it hits the eaves of
the house.

The eaves, by definition, have no ceiling underneath
them. The eaves are the part of the roof that
hangs out beyond the walls of the house. With
no ceiling to heat them, the eaves tend to refreeze
water that tries to run down the roof and fall off
the house. Instead of falling off the house, the water
freezes again and becomes an ice dam on top of the eaves.

I'll summarize ice dams this way:

1. It is heat rising from the house
   that causes snow to melt at cold
   temperatures
2. If is is cold enough, the melting
   snow will refreeze when it hits the
   eaves of the house
3. If enough ice forms on the eaves,
   the ice creates an ice dam
4. If an ice dam becomes serious
   enough, it causes water to back up
   on your roof and your roof leaks in
   the middle of the winter

There's a lesson in all this: An
ounce of prevention is worth a pound
of cure. Another lesson is to take
care of a small problem before it becomes
a big problem.

Inadequate ceiling insulation is a small
problem that can become a big problem
if this problem turns into an ice dam.

I realize that some contractors will
suggest that you ventilate your attic
better to get rid of the heat. We
had a contractor suggest this to us.

We already have passive ventilation
in our attic. This particular contractor
suggested active ventilation. He wanted
to poke a hole in the roof and run an
electric fan.

I found this solution annoying. If we
did this, it would mean we were pumping
heat out of the house at a much greater
rate. I felt that this would inevitably
lead to slightly higher heating costs.
There had to be a better solution.

It was then that I talked to my cousin
and we decided to hire him. I'm so grateful
to my first cousin for the wonderful work
he did on our house.

There's another lesson in this: Some people
do much better work than other people. It
pays to seek out the best to get the best.

The older your house, the more likely it is
that it has inadequate ceiling insulation.
Our house was built in the early 1950s when
fiber-glass insulation was a new idea. Our
original attic insulation was only R-8, which
is totally inadequate by today's standards.

Another life lesson is that there is always
a better way to do things.

Ed Abbott