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GAZETTE Newspapers
By: Arthur S. Lazerow
Prevent Ice Dams This Winter
Question: Robert and Valerie
from Clarendon VA emailed: “So far this Winter there has been
very little snow, so we are betting on a big snow fall after New
Years. Several years ago we lost the gutters on both the front
and rear eaves of our home due to ice buildup from a snow storm
that dropped only 8 inches on our roof. Is there anything we
can do in advance of a storm to prevent this from occurring
again?
Answer: The fact that you
lost your gutters as a result on such a small storm is
distressing. I hope your gutter contractor secured the new ones
better than the older gutters that came tumbling down!
Understand how ice forms in gutters. After a major snowfall,
snow covers your roof. The effectiveness of your attic
insulation and the resultant attic temperatures will determine
whether or not you have a problem with ice in your gutters. The
snow may remain on your roof for an extended period and melt
only during daylight due to solar warming if your insulation
effectively keeps the heat in your home. This water from melted
snow then runs off in its liquid form and does no damage.
However, insulation becomes inadequate over time as it
compresses and loses its insulating ability or original
construction did not include sufficient insulation. In either
case, heat from your home will escape your attic and melt the
underside of the snow load sitting on your roof. This is
especially damaging at night when winter temperatures are below
freezing. As the melted water drips down the roof, it finds
your gutter at the roof eave. Exposed to freezing temperature
and with no heat from the attic to keep it liquid, the ice melt
refreezes. As this process continues, the amount of ice in the
gutters accumulates until the weight brings down the gutters.
As a homebuilder, I would ride around my communities under
construction after a snowfall to find homes with no snow of the
roof. This was a sure giveaway that the insulation contractor’s
crew missed a house or installed too little insulation. In our
area, R-30 (12-14 inches of blown-in fiberglass insulation) is
the required insulation factor. In colder climates, R-38 is
recommended.
I recommend that you go into panic mode over this issue to
protect your new gutters and keep water from entering your
home. If there should be a snowfall before you arrange with
contractors to correct your problem as suggested below, one
thing that can be accomplished immediately after the snowfall is
to remove the snow from the roof. I don’t recommend that a
homeowner climb onto an icy roof with a snow rake, but many
landscape contractors have employees experienced to do so.
As soon as possible, reinsulate your attic. Assuming you have
blown or batt insulation on the attic floor, which is typical in
the Washington DC area, arrange for an insulation contractor to
bring your insulation up to at least an R-30 level, if not
greater. If you don’t know of such a contractor, go to
Contractor.com, click “Display All Job Types”, put in your
zip code and click insulation to find local contractors who have
been screened. Also, making your top floor ceiling airtight will
help reduce heat convection into the attic.
At the same time, arrange for an electrician or a heating
contractor to install an attic fan through the roof.
Regardless of the season, mechanical ventilation is very
helpful. During summer months, forced ventilation pulling
cooler outside air into the attic helps to avoid heat buildup
from radiant heat, thereby reducing air conditioning expense and
making your air conditioning system more effective.
With snow on your roof during the winter, turn on the attic fan
to pull cold air into the attic and force any warmer air out.
This eliminates or at least reduces heat buildup escaping into
the attic from your home through the attic insulation or other
openings in the top floor ceiling. Freezing air in the attic
prevents melting the snow load on the roof, preventing the
development of ice in your gutters.
Finally, there are material systems that can be installed under
roof shingles to prevent roof ice melt, but they are somewhat
awkward to install under existing roofs. One system is an
insulating product between the roof deck and roofing materials.
Another system consists of electric heating cables to melt the
snow under controlled circumstances. I recommend you contact a
knowledgeable roofer or do a web search under “Ice Damming” for
additional information.
Nonetheless, be
proactive to protect your home. Ice damming is a problem that
is controllable with the appropriate renovations to your home.
Have a question relating to a housing or environmental issue?
To contact Mr. Lazerow, click on “Contact Us” at
Albaninspect.com. Mention “Gazette Newspapers” in your
question. Every question will be answered and some will be
included in this column.
Arthur Lazerow, president of Alban Home Inspection Service,
Inc., is a nationally certified ASHI home inspector, having
performed more than 6000 inspections during the past 12 years.
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