So,
what does that have to do with my roof?
Let's
start with some basics. The ground does radiate some heat, even in
winter. Even when the outside air temperature is below 32 degrees
Fahrenheit, mother earth continues to radiate its heat to the
earth's surface and does battle to delaying ground frost.
Eventually, the air temperature continues to drop until frost
occurs. Now let?s cross that bridge. The air surrounding the
bridge, including under it, is far from mother earth?s heating
influence. So, the cold air is going to do its job. Any water or
moisture can now freeze that is on the bridge surface. Keep this
thought while we go to your winter climate home.
It's two
o'clock in the afternoon and look at all that beautiful snow on
your roof. As you enjoy the warmth inside your home, the heated air
rises against the ceiling and actually raises the air temperature
of your attic. Together, the warming attic and the sunshine beading
down on your roof (about 38-40 degrees Fahrenheit) will start to
melt the snow.
Now,
your roof eaves tell you the snow is melting by the constant
dripping. Then, the sun goes down and so does the air temperature.
The constant dripping at the eaves of your roof slows down and
starts to freeze. Remember why the ice on the bridge formed? The
same applies here, your eaves are just like the bridge. There is
freezing air just waiting for that next drip. Actually, this is the
beginning of icicles, destructive, roof damaging icicles. As the
icicles get longer and longer, they also get wider. To make matters
worse, the warm home continues to melt the snow on top of the roof.
The melting snow rolls down to the eaves and collects against the
eave gathering ice. This is known as ice damming.
The
destructive ice starts to work its way back up the roof and under
the shingles. Your roof protection has been compromised. It's just
a matter of time before this repeated scenario makes its way, as a
ceiling stain. So, what can be done to reduce destructive ice
damming? Insufficient attic ventilation and inadequate attic
ceiling insulation are the first things to look for. The proper
amount of ceiling insulation will minimize the upward heat loss
from the living area, which will then allow the attic ventilation
to do its job.
As far
as knowing if there is sufficient ventilation in the attic, you can
simply record the outside air temperature and then the attic
temperature. Ideally, your attic space should be within 15 degrees
Fahrenheit of the outside air temperature. The overall goal is to
influence the accumulated snow on your roof via effective ceiling
insulation and ample attic ventilation, so the snow collectively
and uniformly melts off. Depending on your attic configuration,
there is a formula to figure it out. However, it's then time to
call a qualified licensed general contractor.