Rim joist spray foam insulation in Redcliff is the best-value item on almost any house in town, and with about 62% of local homes built before 1991 it applies to most of them. The rim joist is the band of wood where the floor framing lands on top of the foundation wall. It runs the whole way around the house, it is only a few inches tall, and in this vintage of construction it was built with no air seal, no sill gasket worth the name, and whatever scrap of insulation someone pushed in from the basement side.
Why such a small surface matters so much
Three things come together in that band and nowhere else in the house does that happen.
It is the junction of two different materials, wood on concrete or wood on block, assembled by different trades on different days, with a gap between them that nobody was responsible for closing.
It is at the top of the basement, where warm air collects and wants to leave. Air leakage is driven by pressure difference, and the pressure pushing air out of a house is greatest at the top of the heated volume. In a house with a basement, the rim joist is a long continuous opening sitting close to the top of the lower storey, and the air moving out of it is moving all winter, not occasionally.
And it is cold, because the joist ends are in direct contact with a foundation that is in contact with the ground.
The old answer and why it failed
The usual find is a piece of batt stuffed into each bay from the basement side. That does almost nothing, for a reason worth understanding. Air passes straight through fibrous insulation. So the batt neither seals the joint behind it nor stops the air, and it adds one new problem: it holds warm humid basement air against the cold rim board long enough for that air to give up its moisture there. The wood then stays damp behind an insulation layer nobody will ever look behind.
What we actually do
Closed-cell foam is applied directly into each joist bay, against the rim board and across the sill plate, carried onto the top of the foundation wall and a short way down the concrete and a short way onto the underside of the subfloor. That one pass seals the material junction, seals the bay, insulates the joist ends, and at around two inches is the vapour control as well, which is why the moisture problem does not simply move inward.
It is also fast. A rim joist job on an ordinary house is a short visit, which is part of why it is the first thing we suggest.
What gets in the way
Ductwork, wiring, plumbing and gas lines run along the rim in a finished basement, and whatever is there has to be worked around rather than through. Where the basement ceiling is finished, access may mean opening a strip along the perimeter. On an older house there is sometimes rot in a joist end, usually under a door or where a downspout discharged, and that is repair work that comes before foam, not instead of it.
Who you are dealing with
Rim joist spray foam insulation Redcliff is work we take care of ourselves. We scope it, we quote it, we schedule it, and our own installers are the ones holding the gun.
Rim Joist Spray Foam Insulation Redcliff: Common Questions
Can the rim joist be done on its own? Yes, and often it should be. It is a self-contained job, it is quick, and it does not require committing to a basement renovation.
There is already insulation in there. Is that enough? Almost certainly not. Fibrous insulation does not stop air and it holds moisture against the rim board. In this stock it usually has to come out.
Will it cause moisture problems in the wood? Closed-cell at adequate depth puts the dew point inside the foam rather than on the joist, which is the opposite of what the existing batt is doing.
How much does rim joist spray foam insulation cost in Redcliff? Priced per board foot of sprayed area, and the area is small, which is why the return is good. The variables are how much old material comes out and whether a finished ceiling has to be opened for access.
How do I choose a rim joist spray foam contractor in Redcliff? Ask whether the foam will be carried onto the sill plate and the top of the foundation wall, not just into the bay. That continuation is the part that does the sealing.
Size the assembly with the R-value calculator, then get a free Redcliff quote. More on Rim Joist Spray Foam Insulation Alberta province-wide.