Rim joist spray foam insulation in Ponoka treats the band of timber sitting on top of the foundation where the floor structure lands. It is a narrow strip around the whole building, it is rarely sealed, and in this town it undoes the room people care about most.
The draught at ankle level in the room you actually use
Cold air entering at the band is heavy, so it stays low. It spreads across the basement floor and cools the underside of the floor above. In a Ponoka house where the lower level is a genuinely used room, that is felt directly rather than as an abstraction: it is the reason the floor is cold to sit near, the reason a heater at one end never fixes the other, and the reason somebody puts a rug down instead of solving it.
What is in the bays now, and why it does not seal
Open a basement ceiling here and the bays hold nothing, or a piece of batt somebody pushed in. Batt is a resistance material. It slows heat moving through it and does nothing about air moving around it, and the band is fundamentally an air problem: the joint between the sill plate and the top of the concrete, and the gap at each end of every joist bay. Closed cell foam goes in as a liquid, gets into those joints and stays stuck to both surfaces.
Older houses here have more than one band
A good number of Ponoka houses have been added to. A back addition, an enclosed porch, a lower level put in under part of the building. Each brings its own band and its own junction with the original structure, and that junction is the least likely part of the house to have been sealed by anybody. They get done in the same visit, because sealing one and leaving the others simply moves the draught somewhere else.
Reached in part of a day where the ceiling is open
The practical argument is access. In an unfinished basement every joist bay is visible from below, there is nothing to demolish, and the work is finished in part of a day. Where a basement has already been developed it is a different conversation and the cost of reaching the band is real. Anybody planning to finish a basement should do this before the ceiling goes up rather than after.
Rim Joist Spray Foam Insulation Ponoka: Common Questions
Why is the basement floor always cold? Cold air enters at the band and stays low. That is the usual cause and it is the cheapest to fix.
Is spray foam still worth it if we already have batt in the bays? Batt does not seal the joints, and the joints are the point. It comes out.
Does an addition mean the house has more than one rim joist? Then there is a second band and a junction between them. Both get done in the same visit.
Size the assembly with the R-value calculator, then get a free Ponoka quote. More on Rim Joist Spray Foam Insulation Alberta.