Rim joist spray foam insulation in Westlock is the job we recommend first on more houses than any other, and with around four in five homes here built before 1991 it applies to most of the town. The rim joist is the band of framing that sits on top of the foundation wall and carries the floor. It is perhaps a foot tall, it runs the entire perimeter of the house, and on a house of this age it is almost never insulated in a way that works.
What is actually there now
Pull a piece of batt out of a rim joist bay in an older house here and three things are usually true. The batt is loose rather than in contact with the wood, so air circulates behind it. There is no air seal at all at the joint where the sill plate meets the top of the concrete, which is a straight line of gap around the whole building. And the batt itself is discoloured in a band, which is the dust filter pattern left by air passing through it for decades. That staining is the most reliable evidence of leakage anyone can find in a house without instruments.
Why this detail is worse in a climate with no thaw
The rim joist sits directly on the foundation, and the top of that foundation is in contact with ground that freezes deep north of Edmonton and stays frozen. There is no chinook to bring it back above zero mid-season, so that concrete is a cold sink for months continuously rather than intermittently. The wood sitting on it is therefore cold, and any warm humid basement air reaching it has a long uninterrupted window in which to condense. In a finished basement, where nobody looks behind the drywall at that level, the consequences accumulate unseen.
What the repair is
Closed-cell foam sprayed into each bay, covering the rim board, the sill plate, the top of the foundation and the ends of the joists in one continuous application. It bonds to concrete and wood alike, which means the joint between them is sealed rather than covered, and at the depth normally used it is its own vapour retarder, so the dew point ends up inside the foam instead of on the cold wood. It fits the irregular bays around beam pockets, duct chases and the places where a pipe was run through, which is precisely where cut materials never fit.
Why it is the best value job in these houses
Three reasons, all of them specific to this stock. The area is small, so the material cost is modest. The leak is continuous and runs the full perimeter, so closing it changes the whole-house air leakage measurably. And in most of these basements it is reachable without demolition, because the joist space above a mechanical room or a storage area was never finished. A job that costs little, fixes a lot and requires nothing to be torn out is rare in retrofit work.
We take care of the work
Rim joist spray foam insulation Westlock is quoted, scheduled and sprayed by us. Our own installers are on the job, and the number you are given is the number we stand behind.
Rim Joist Spray Foam Insulation Westlock: Common Questions
Where exactly is the rim joist? In an unfinished basement, look up at the perimeter. The band of wood between the top of the concrete and the underside of the floor above is it.
Our bays already have insulation in them. Loose batt in a rim joist bay does not stop air, and the sill-to-concrete joint is almost always unsealed behind it. The old batt comes out and the bay is sprayed.
Can it be done if the basement is finished? Often only in the sections that are still open. Where the ceiling is boarded out it becomes a question of access, and we will tell you honestly what can be reached.
How much does rim joist spray foam insulation cost in Westlock? It prices per board foot of sprayed area, and the perimeter of a typical house is a small area, so this is the least costly item on most quotes we write. Clearing stored material away from the walls beforehand shortens the job.
How do I choose a rim joist spray foam contractor in Westlock? Ask whether the foam will cover the sill plate and the top of the foundation, not just the face of the rim board. The joint is the leak.
Size the job with the R-value calculator, then get a free Westlock quote. More on Rim Joist Spray Foam Insulation Alberta province-wide.