Rim joist spray foam insulation in Edson treats the band of timber that sits on top of the foundation and carries the floor above it. It is a narrow strip around the perimeter of the house, it is almost never sealed properly, and in this town it is doing something slightly different from what it does elsewhere.
Damp air in the band, not just cold air
Most pages about this detail talk about cold air coming in. Here the air arriving through an unsealed band is also carrying moisture, because the ground and the air outside an Edson house stay damp for most of the year. That air meets the coldest timber in the building and gives up what it is carrying right there. Batt stuffed into the bay does nothing to stop it, because batt does not seal, and over years the band is the part of the structure that shows it first.
Snow banked against the band, and what it hides
The band sits exactly at the height the snow reaches. That means for a good part of the year it is buried, which keeps it slightly warmer and also keeps it wet as the drift works through its thaw cycles. It also means nobody can see it from outside for five months of the year, so anything happening there happens unobserved. The inspection that matters is the one done from inside, in the basement, where the joist ends are actually reachable.
Half the houses here have never had this touched
This is a stock built in waves by people who needed housing quickly, and the band is the detail that gets skipped in a hurry. Open up almost any basement ceiling in this town and the bays are either empty or hold a piece of batt somebody pushed in later. Neither is doing the job. Closed cell foam sprayed into each bay seals the timber, the sill and the top of the foundation as one continuous surface, which is what the detail actually needs.
Doing it in the same visit as the crawl space
A lot of Edson houses have an addition on a crawl space, and that means there is a second band where the addition meets the original building. Both are reached the same way, with the same equipment, on the same day. Doing them together costs far less than doing them separately, and it avoids the common outcome of sealing one and leaving the other, which is a house where the draught simply moves. Where the basement is already open for other work, this is the cheapest thing on the list to add.
Rim Joist Spray Foam Insulation Edson: Common Questions
How big a job is it? Small. No demolition where the ceiling is open, and it is usually done in a day.
Why is batt not enough in the rim joist? Batt does not seal, and in a damp climate that is the part that matters. It comes out.
Is there more than one band on our house? If there is an addition on a crawl space, yes. They get done in the same visit.
Size the assembly with the R-value calculator, then get a free Edson quote. More on Rim Joist Spray Foam Insulation Alberta.