Attic spray foam insulation in Edson is air-sealing work first and depth second, and the reason that order matters here is on the roof rather than in the attic. This is a town where the snow that falls in November is frequently still up there in March.
A roof that keeps its snow all winter
Out on open prairie a good deal of snow leaves the roof on the wind. Here it does not. Shelter from the trees and from the valley means an Edson roof carries what it is given, and it carries it as a continuous blanket rather than in drifts and bare patches. That blanket is itself an insulator, which sounds helpful and is not, because it holds whatever heat is escaping from the house right up against the underside of the snow.
Ice damming where the snow never leaves
That is the mechanism behind the thing everybody here recognises. Heat leaking through the ceiling melts the layer of snow touching the deck, the water runs down to the eave where there is no heat under it, and it freezes there. Do that for four months without a thaw to clear it and the ice builds into something that pushes water back up under the shingles. Heat cables and roof raking deal with what is already happening. Sealing the ceiling plane deals with why it is happening at all, which is the only version that stops recurring.
Trees over the roof change what the eave has to cope with
An Edson roof under conifers collects needles continuously, not seasonally, and they end up in the gutters and packed into the ventilation openings at the eave. That matters a great deal once the ceiling below is sealed, because the whole strategy depends on the attic staying cold and ventilated. Blocked intake with a well-sealed ceiling above it is a worse attic than an unsealed one. The vents get checked and cleared as part of the work rather than being assumed to be doing their job.
What a wet attic looks like where nothing dries
The tell in this climate is not a stain, it is frost. Moist air from the house reaches a cold deck, condenses, freezes, and builds up over months because there is no mild spell to clear it. Then it lets go all at once in spring and appears as what looks like a roof leak in a roof that is perfectly sound. Anybody in Edson who has had water appear from the ceiling in April on a dry day has almost certainly had this rather than a leak, and the fix is at the ceiling plane rather than on the roof.
Attic Spray Foam Insulation Edson: Common Questions
We get ice dams every winter. Is more insulation the answer? Sealing the ceiling comes first. Depth on an unsealed ceiling mostly disappoints, and here it disappoints for four months.
Why did water come through the ceiling in spring when the roof is fine? That is usually attic frost letting go rather than a leak. It is worth looking at before spending on the roof.
Do the eave vents matter that much? More here than almost anywhere. Needles pack them, and a sealed ceiling needs the intake working.
Size the assembly with the R-value calculator, then get a free Edson quote. More on Attic Spray Foam Insulation Alberta.