Have you
ever seen a home that has newer looking or different color shingles along the
edge of their house? This typically
indicates that the homeowner has experienced severe problems from ice dams.
Yesterday, most of us in Michigan experienced a wet, sloppy snow storm. Many home owners are likely to experience ice dams as a result.
An
ice dam is a build up of ice and water that works its way under shingles. When
snow from the peak melts (caused by warm spots in the attic), water slowly runs
down the roof. When the water hits a
cold spot on the roof (usually at the eaves), the water refreezes. As more
melting water hits the cold spot, it begins to "stack up" and
eventually works its way underneath shingles and sheathing.
The cause
of the problem is either inadequate insulation, ventilation, or both. How to reduce
the chances of ice dams:
1. If your attic space is unfinished (not used as a living space), the goal is
to have the temperature inside the attic close to the outside temperature. To
accomplish this you need:
a. sufficient insulation between the floor joists of the
attic;
b. soffit or fascia vents;
c. roof or ridge vents;
d. all sources of heat loss, such as bathroom or kitchen
vents, heating ducts, or heat pumps, well insulated to minimize loss of heat
from them to the attic space.
Doing all
the above allows cold outside air to come in at the bottom of your roof and
escape through the top of the roof taking along any heat lost to the attic
space.
If you
have all the ingredients and are still experiencing a problem:
a. inspect the insulation in the floor to insure it's not
jammed against the end of the roof to close off circulation from the soffit
vents; if it is, then pull the insulation away from the roof edge to allow air
to circulate;
b. inspect soffit vents to see that they are open and not
painted shut. Sometimes vinyl soffit vents are installed over solid wood
soffits making the vinyl vents useless. If so, remove vinyl soffits and drill
2-or-3" openings through the solid wood soffits every 12-to-18"
respectively;
c. check roof vents. Properly installed “ridge vents” are
typically preferred over “can vents”.
d. close any open gable vents. Air can short circuit by
coming in gable vents rather than by coming in the soffit vents.
2. If
your attic space is used as a living area and you have soffit and roof vents,
fixing the ice dam problem can be expensive. You need to allow air to flow
between the roof and the insulation. The ceiling and insulation must be
removed, special ducting panels must be installed between each rafter, then the
insulation and ceiling can be re-installed.
3. Homes
in Michigan
should have an ice shield barrier installed along the roof edge. Existing
shingles must be removed along the roof edge. The barrier is 36" in
width. Oftentimes more than one course of ice and water shield is
needed. The shield is like a pool liner and doesn't allow water to seep
through it.
Can owning a metal roof system help with the ice
dam problem? Yes it can. In short, snow doesn't stay up on a metal
roof as easily as it does on a granulated asphalt roof. No snow on the
roof to melt, no ice dam. In fact, with metal roofing, we often have to
strive for the opposite effect - keeping snow on the roof! Since snow
comes off of the roof so effectively, we often want to install "snow
guards" along the eave edge of the roof especially along walkways and
above doorways to minimize avalanching snow. At Metal Roofs of Michigan, we specialize in
addressing all the issues that a roof in Michigan
faces and strive to provide you with a beautiful, long lasting roof that is
free from those pesky ice dams.