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Your roof is exposed to the hottest summer
head AND the coldest winter freezes. Maintaining a healthy roof can
reduces climate control costs, not to mention the expense of water
damage.
MAINTAIN GOOD
VENTILATION
Good Roof Ventilation Makes A
Difference
Modern home construction methods result in better insulated and
tighter homes, which saves you the homeowner money on energy bills, but
makes the need for a well ventilated attic even more important. Attic
ventilation is necessary to prevent moisture problems, to prevent heat
build-up, to reduce heating and cooling cost. The benefits of proper
ventilation for the homeowner are a cooler attic in the summer, a dryer
attic in the winter and protection of the structural integrity of the
home from moisture damage.
Summer Heat
In the summer, heat builds up in the attic space, which will cool at
night if the attic is properly ventilated. However, if the attic is
unventilated or ventilated incorrectly, the heat will build-up over a
period of days and continue to increase the temperature inside the
attic. According to Air vent Inc.’s "Principles of Attic
Ventilation". A 90-degree day with no attic ventilation can heat
the roof sheath to 170 degrees or more. Heat radiating from the
sheathing down to the attic floor can raise its temperature to as much
as 140 degrees. Without adequate ventilation, today’s heavier
insulation will absorb and hold more heat built-up during the day and
make the attic less likely to cool at night. Overheated ceiling
insulation conducts the heat through the ceiling down to the residents
of the home. This causes the air conditioning system to operate for
longer periods of time to reduce the heat.
Winter Moisture
The well-insulated attic also will hold moisture in the winter and
moisture causes considerably more problems than excessive heat. During
the winter, air inside the home is warmer and carries more water vapor
than the colder, dryer air into the attic. Cooking, laundry, showers and
humidifiers add moisture to the air inside the home. Atmospheric
pressure causes the vapor moisture to naturally migrate from high
humidity air to low humidity air and as it moves into the attic, the
moist air will condense into liquid on the cooler rafters, trusses and
roof sheathing. As the air gets colder, its ability to absorb moisture
is reduced. And, as the insulation levels are increased in the ceiling
the attic becomes colder and more likely to retain the moisture, which
can damage the structure. In some parts of the United States such as the
ChicagoLand Area, snow melting on a warm roof surface can cause an ice
dam. The melting snow, usually near the ridge, runs down to the colder
roof overhang and then refreeze into ice. Subsequently melting of the
snow on the roof can accumulate as a pocket of water that eventually
backs-up under the shingles to cause major damage. The results can be
soaked insulation, stained sheet rock or peeling paint. In some cases,
the build up of the ice weight can cause structural damage.
ICE DAMS
Many homeowners in the Chicagoland area
have experienced a winter storm condition called "Ice
Damming". Ice dams occur when a sequence of weather conditions
takes place during a brief time frame. Conditions experienced in the
2000-2001 winter season usually only occur every five to seven years but
3 out of the last 6 winters have produced such conditions.
What Is An Ice Dam?
Ice dams are formed when the gutter system becomes filled with moisture
which when frozen forms a "dam" at the eaves of the roof. When
additional moisture gathers on the roof and is not able to run off due
to the "dam" at the gutter line, this moisture becomes a
frozen layer on the roof surface and may back-up towards the peak of the
roof.
What Causes My Home To Leak?
Ice dam related leaks occur when warm, heated air from the building
migrates through the roof deck and warms the underside of the roof. With
outside temperatures keeping the top outside layer of moisture frozen
the warm deck/roof melts the bottom layer of ice returning it to a
liquid state. This underlayer of water will run down the shingles until
it meets the "dam" at the gutter line. With no escape route,
the water pools, then backs-up underneath the shingles and enters the
attic area through nail holes and seams in the roof deck.
Why Does My Roof Not Keep The Water
Out?
Shingle roof systems are designed to channel water from the high points
of the roof to the lower sections where it should exit the roof either
into the gutter system or simply onto the ground. Shingle roof systems
are not designed to hold water or prevent water from entering that runs
or is blown uphill.
Ice dam related leaks are caused simply
because the water could not escape from the shingled roof area. This is
not a design flaw with the roof system or an indication of a poorly
installed roof. Ice dams are winter storm conditions, which prevent the
shingle roof system from shedding water as designed.
What Can I Do When An Ice Dam Happens?
The only corrective action that can be taken is to remove the barrier of
ice at the gutter line or to remove the ice build-up on the roof area
before it melts from underneath. It must be noted that working on a roof
under these conditions is extremely dangerous. The risk of injury should
always be weighed against the cost of water damage repair. Your best
move is to call Avondale Roofing.
Also, in removing ice from the gutter and
roof, you may cause damage to these areas that will require professional
repair. Again, the cost of water damage repair may be less than the cost
of a roof, gutter repair or professional help.
What Can I Do To Prevent Ice
Dams?
While there is no "cure" for ice damming, the following steps
can minimize the chance your home or building will be affected:
- Make sure your attic area has adequate
insulation.
- Make sure your attic insulation does
not cover your soffit air in-take vents. Add soffit vents if your
home currently does not have any.
- Make sure your attic area has
sufficient air exhaust outlets (gable vents, ridge vents and free
air vents) and that the airflow is distributed throughout the attic
space. Peak mounted ridge vents such as Shingle Vent II maximize
airflow in attic areas.
- Products such as an ice & water
shields can be installed at the eaves of the home, around dormers
and in the valley areas under the shingles, which will prevent water
from entering the home unless it dams higher the protection,
provides.
- Homes and buildings with cathedral or
open ceilings may want to consider installing ceiling fans near the
peak of the ceiling to help push the warmer air away from these
areas.
Who Is Responsible For Ice Dams And
The Resulting Leaks?
Ice dams are the result of winter storm conditions. Because they are
storm related, and not a roof flaw, damage caused by water is not
covered by a shingle manufacturer under Avondale Roofing's Warranty.
Remember, sloped roofs are designed to shed water to the ground not hold
water.
There are many products on the market to
improve the capability of established homes to fend off ice dams leaks. Avondale
Roofing is able to provide an ever-increasing number of products and
information for re-roofing clients to choose from.
The final responsibility remains with the
homeowner when re-roofing to weigh the cost of prevention and protection
products against the possible cost of damage and inconvenience if an ice
dam leak occurs.
© 2001, Avondale Roofing, Inc. Niles, Illinois USA
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