Ice Dams

[drmoss_ca]

No, not talking about frigid horses, but the kind of nonsense you get on the roof. I have a total of seven skylights on various roofs around this house, and they bring some troubles. When there is two or three feet of snow on the roof, the skylight lets enough heat through to melt the snow. The melt water trickles down into the snow below the skylight, eventually leading to the formation of ice along the roof edge. Within a couple of days this can be a foot thick, even on a roof with otherwise wonderful insulation. Then any further meltwater has nowhere to go and is dammed up above the ice, eventually backing up under the shingles and appearing inside the house as a drip, which quickly ruins hardwood floors. So I get out the ladders and hack away at the ice to cut channels through it below the skylights. This is hard work, but mitigated if you have a good axe. I really mean that—a blunt axe blade means hammering at the ice for several hours, but a sharp edge means cutting through it in minutes. The reason I mention this on SMF is that good axes involve sharp edges, and straight razor users have some experience at creating those. I have a Granfors Bruks small forest axe, and it sharpens really well—yes, you can cut forearm hair with it. To get it to that point I use a carborundum stone, a single-cut mill file (bastard on one side and medium/2nd cut on the other), then a Lansky diamond rod to finish. It seems a shame to take an edge like that and ruin it on chopping ice, but in the end, that's what edges are for. Use and ruination. Axes are interesting and possibly worthy of more discussion here (any experience with Leveraxes?), but to get back to my topic, once I have a channel I do something just a little bit (pun intended) weird. I ask the boss for an old pair of tights/panty hose, then proceed to fill them with calcium chloride. Once I have a CaCl2-stuffed pair of legs, I place the body of the panty hose on the roof below the skylight, and arrange the legs to dangle down to the gutter. This provides long-lasting ice-melting capability and keeps the channel open for long enough to see me through the worst part of the winter. I swear each year to use the snow rake after each and every snowfall to clear the bottom two feet of each roof surface before ice dams form, but I never seem to manage it. Next year I might look at heating cables, but I hear they can bring as many problems as they solve.

Any good tips to help me out?

Chris

[ShadowsDad]

Other than what you outlined that's about it. The problem as you also discussed is lack of insulation, but how do you insulate a skylight?

Go easy with the axe as it can cause many problems, but it must be done. I'm thinking not only going through roofing with the edge, but in breaking away shingles just by the force of the pounding and ice clinging to the shingle.

Edit: I just looked at the leveraxe, and it's more for splitting wood. They aren't designed to take an edge.

[brothers]

Chris, instead of an axe (I use mine for chopping wood, etc. like a lumberjack), I'd recommend a mason's single edge rock spitting hammer. They're shorter, lighter than an axe, and made for one handed use. Just heavy/light enough to allow you to regulate the amount of arm/shoulder force needed with each blow, and on the other end is a flat end that could be used when you get down close to the surface and do not want to accidentally cut through. That's what I'd get for the job you decribe.

[Squire]

I'd hire a strapping young fellow who works at the local tire shop because they have strong forearms and welcome the extra cash.

[Ouchmychin]

How about laying heating tape under the edges ot your shingles. I never tried anything like that but with enough watts maybe you could prevent any ice formation. You would need to fill in under the shingles with a mastic of some sort to block water there. Is that a solution or just a pipe dream?

[ShadowsDad]

Yes Pete, that's commonly done. But not after the fact.

Come to think of it, I've seen strips of aluminum put under the 3rd or 4th row of shingles "up" from the edge and exposed to the eye (and weather). That prevents the ice dam from backing up and the water getting around the shingles. No reason heat tape couldn't be put under the aluminum sheet that I can think of. My neighbor has this treatment but that didn't stop his ice dams this year. They just formed higher up than normal.

We have a metal roof and no longer have ice dams because the roof sheds ice and snow. No buildup, no ice dams. It would shed me too if tried to go up there.

While I'm thinking along these lines... Chris talk to a contractor specializing in roofing and see what he says about putting a "cricket" up there (google "roof cricket"). That won't take care of the problem now, but it might in subsequent years. See what he says.