ice dam &
Snow Removal
In PA, OH & WV

Calcium chloride, carefully and as a stopgap — never rock salt. Rock salt corrodes aluminium gutters, flashing and downspouts, kills whatever it runs off onto, and stops working around 15°F, which is most of a snowbelt winter. The method homeowners pass around — filling a stocking with calcium chloride and laying it across the dam to open a drainage channel — does work in a pinch, and it is worth knowing if water is coming in and nobody can get to you tonight. What it does is relieve pressure, not remove the dam. It also does not stop the melt-and-refreeze cycle that built the dam, which is a heat-loss problem in your attic, not a weather problem on your roof.

Almost certainly. Striking ice that is bonded to shingles takes granules, splits shingles, and tears flashing, and in cold weather, asphalt is brittle enough that it breaks rather than flexes. Plenty of roofs get their real damage during the removal, not from the dam. The same applies to picks, axes and anything else with an edge. What you cannot see while you are swinging is where the ice ends and the shingle begins. This is the single most common way a manageable winter problem turns into a spring roof repair, and it is why we do not do it that way.

Low-pressure steam. It melts the ice away from the shingles and lets it release, rather than breaking it off and taking the roof surface with it — and it works at temperatures where chemicals have stopped doing anything. It is slower than swinging a tool at it and that is the point: the roof underneath is intact afterwards. Pressure washers are not the same thing and should not be used — high pressure strips granules and drives water under the courses, and the water refreezes. If you are getting quotes, ask specifically whether the crew steams or chips, because that one answer tells you what condition your roof will be in come April.

Partly. Pulling the snow off the bottom few feet of the roof removes the material an ice dam forms from, and it is the one preventative thing a homeowner can safely do from the ground. Two limits worth knowing. It only reaches the lower edge, so heat still escaping into the attic keeps melting the snow further up and that meltwater still runs down to a cold eave. And a metal-edged rake dragged across shingles takes granules with it — if you are going to use one, use a foam or plastic head, work downward, and stay off the ladder. Never rake near a service line.

Weight is what matters, not depth. Roughly a foot of fresh light snow is comparable to an inch or two of packed old snow or ice, so a shallow, dense layer after a thaw-and-refreeze can load a roof harder than a deep fresh fall. The warning signs are structural and they are worth knowing: doors or windows that suddenly stick, new cracks in interior drywall or plaster, creaking, or a sagging line in the ceiling. If you see any of those, get people out and call — do not go up to look. Flat and low-slope roofs are the ones to watch first, because nothing sheds on its own.