SailFan wrote:
I have a couple of questions regarding attic ventilation and ice dam
prevention:

My house is a cape cod style, which presents a challenge. In the upper
attic there is plenty of loose insulation, but it is right up against
the roofing at the edges. I know I need to pull this back and put those
foam air channels in. BUT, what about the area between my attic floor
and the bottom edge of the roof (10-12 feet, probably)? I am not sure
yet whether there is any chance for air to travel this path. I have no
access to this area other than by tearing out walls or the roof. Gah!

I am looking at installing a powered gable vent. I have a continuous
ridge vent now. If I can establish air flow from the soffits to the
attic, it would seem that I should block the ridge vent so that the
powered gable vent pulls air up under the roof? Also - the powered
gable vents I saw at Menards/Lowes/Home Depot are thermostat
controlled. They go off at the set temperature. These thermometers only
go down to 50 or 60 degrees F. That seems too warm to me - in the
winter it would seem that I would want the fan to go off at a much
lower temp. Am I missing something here?

Thanks for any advice!

Matt


Had a similar situation. Actually there are 2 winter
problems: warm roof causing ice dams and lack of
ventilation, causing condensation on rafters/roof deck
and resulting in mold growth.

I put a gable vent fan in and a louvered intake at
the opposite gable. Thermostat is bypassed in winter
and the fan runs under manual control from a speed
control ("dimmer" for motors). If I set it so the
fan is barely spinning, that's enough to keep the
roof cold AND prevent condensation.

In your case, give it a try without blocking the ridge
vents; it may work just as well.

Jim