so i have this house in ski country that ice dams pretty nice. there’s no easy way to make the roof cold (cathedral ceilings mostly covered with T&G fir) so i’m looking at putting heat tape aka heat cable on the roof over the eaves.
does anyone know how much these systems cost to run? i’m especially interested in whether it’s worth it to pay the huge cost difference to get self-regulating heat tape. if so, any leads on good deals for a 400′ roll would be appreciated
also, i have seen some installations where they only tape the valleys and the first 12″ of roof (on a house with 36″ overhanging eaves) and cover that up with copper flashing. looks “nice” but i would think you would need to run the tape up the roof until you weren’t over the eaves anymore.
oh, and this isn’t a vacation home, it’s my principal residence which hopefully will mean i don’t need super snazzy controls.
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If you can arrange a manual switch, and will use it as needed, that should suffice. You basically only need the cables on when temps are in the 20s or 30s (depending on sun conditions) and there's snow along the eave line. Once they've melted holes through you can turn them off.
Normally you only need to have the cables on for an hour or so at a time, usually in the late afternoon.
Note that if you have multiple exposures with the problem you probably want each exposure on a different switch, since they will not all need heat at the same time.
thanks Dan.
will go with two circuits -- east/west
Do be aware that the standard cable only lasts 3-5 years before it needs replacing. Maybe there's higher-priced stuff that lasts longer, but I'm guessing that none of it will last more than ten years.
Re how far up to go with the cable, normally you'd want to go up the length of the eave, plus a little. Not clear how the copper flashing thing would work, and remember that you shouldn't cover the cable with anything (or cross it with itself, etc) unless the instructions say you can.
If you want something that will last in your winters and with your snowfall, Google for Bylin Engineered Systems.
Pricey, but permanent.
nice website. i guess i don't understand how it can work -- take a house, like one i've seen here with that system. it has a 9/12 roof with 36" overhanging eaves, but the rim system heats only the valleys and the first 12" (on the diagonal) of the eave. so there's almost 33" of space between the end of the rim panel and the start of the warm part of the roof (figuring 45" of roof in that area).