Replies

1. 
   Guest_ | Jul 06, 2000 05:35pm | #1

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   I had the same problem which I fixed by wiring a switch to my attic exhaust fan which allowed me to turn it on as needed. Whenever I had snow starting to melt on my roof I turned the fan on. This house had ridge and soffit vents, so the fan was able to pull air in from the eaves and keep the roof cold to avoid melt.

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   Guest_ | Jul 07, 2000 02:05am | #2

   *Mik:Don't fight it. I lived twenty five years in the snow capitol of the world; Valdez, Alaska. October 15th every year the gutters came down. It was either that or let the ICE take them down. There are times you simply have to accomodate Ma nature.Just my $0.02 worthBob

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   Guest_ | Jul 07, 2000 04:19am | #4

   *Again I have to point out that roof ice is a SYMPTOM, not the PROBLEM.The problem is that valleys are damn difficult to vent, and nothing we do conventionally will adequately handle all valleys. Dare I say it is a venting failure?The point here is that the shnow is being melted by heat leaking out of your house through every opening that is over your head.My wife is looking over my shoulder and said "there goes Rob about ice damming again!"These openings can be plainly visible or behind walls - like plumbing and electrical chases.Air selaing is the key here. Stop the hot sir leaking out of your house and you will stop this ice damming. The real kicker is that you are paying to heat the air that leaks out, melts the snow, causes condensation on the underside of the roof, then damages the shingles and the gutters!! Seem harmlesss and inexpensive now?God bless Carlos, but turning the fan on most certainly doubles the normal convection rate through the conditioned space.I have been doing some research into this and have found that if you look at the data you have to leak TONS of air out of the house to make ice. Because heatloss through conduction just don't cut it. Fred calculated once that there is 38% more lumber in a valley than in the field of the roof. Does it seem practical that any of the valley venting tricks will increase airflow through there by an appropriate amount?Maybe we could discuss alternative to venting to prevent ice damming on valley ridden roofs.-Rob

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   Mik_ | Jul 07, 2000 04:19am | #3

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   I have a roof valley between a 5/12 and 12/12 roof. then a 2 ft. uninsulated soffit. I get tremendous ice/snow build-up. Any help besides heating cables? The cables use too much power and ice would still generate above the cables.