Rim joist spray foam insulation in Cardston is the first thing worth doing in most of the houses here, and on the oldest of them it is not quite the job the name describes. With about 70% of local homes built before 1991 and a share of those much older, what you find when the basement ceiling is opened up varies a great deal by the decade the house was built.
Three different details, depending on the decade
On a mid or later twentieth century house there is a conventional rim board: a continuous piece of lumber at the perimeter, closing the ends of the floor joists, sitting on a sill plate on a concrete wall. On an older house the floor joists instead sit in pockets built into a masonry or stone wall, with no rim board at all, and the gap around each joist end is a direct path from outside to inside. On the oldest, balloon framed houses, the wall studs run past the floor without a plate between them, so the wall cavity is continuous from the basement to the attic. These three details need three different approaches, and only one of them is what a standard rim joist quote assumes.
Why this spot is the leakiest in the house
It is the junction where the foundation, the sill, the floor structure and the wall above all meet, and every one of those was installed by a different trade at a different moment. On houses of this age there is usually no sill gasket, no sealant, timber that has dried and shrunk away from the masonry, and gaps you can see daylight through. It is also the lowest part of the heated envelope, which is where cold air enters while warm air leaves at the top. Sealing the bottom of that loop is what makes the top of it stop pulling.
A joist pocket is a small hole with a large consequence
Where joists bear directly in a stone or early concrete wall, each pocket is an opening sized for the timber plus whatever the mason left for tolerance, and the timber end sits in it unsealed. There can be dozens of them around a house. Individually each is trivial; together they are a continuous draught along the base of the floor. Foam sprayed into and around each pocket seals it and in doing so stops air reaching the timber end, which is incidentally the part of the floor structure most prone to rot in an old house.
Balloon framing turns a wall into a chimney
If the stud cavities run uninterrupted past the floor, the wall is a vertical shaft from the basement to the roof space. Warm air rises in it and cold air replaces it from below, continuously. The remedy is a blocked and sealed stop at the floor line in each cavity, and sprayed foam is how that gets done without taking the wall apart. On a balloon framed house this single detail accounts for a large share of the heat going out of the building.
Look before sealing and do the top as well
Before anything is sprayed, the timber has to be checked. Rot and insect damage at a sill bearing on masonry is a real possibility on a house of this age, and it is a carpentry repair rather than an insulation one. Once the base is sealed, the same treatment at the top of the wall, where the plates meet the attic, completes the pair. Doing only one end leaves half a loop, and half a loop still moves air.
We take care of the work
We are the contractor on rim joist spray foam insulation Cardston, not a referral service. We quote the job, schedule it and stand behind it, and our own installers carry it out.
Rim Joist Spray Foam Insulation Cardston: Common Questions
Our joists sit in the stone wall. Is that still a rim joist job? It is the same location and a different detail. Each joist pocket gets sealed individually rather than a continuous rim board being covered.
What is balloon framing and does our house have it? It means the wall studs run past the floor without a plate, making the cavity continuous. It shows up in the oldest houses here, and it is visible once the basement ceiling perimeter is opened.
Why is this the recommended first job? Because it is the coldest and leakiest accessible surface, the work is confined to the basement, and nobody has to move out.
How much does rim joist spray foam insulation cost in Cardston? Priced per board foot over the sprayed area, so the number follows the perimeter length and depth. Clearing the perimeter and any carpentry repair found underneath are the variables.
How do I choose a rim joist spray foam contractor in Cardston? Ask what they expect to find at the sill on a house of your age. Someone who mentions joist pockets or balloon framing has worked on this stock; someone describing a continuous rim board has not looked.
Size the assembly with the R-value calculator, then get a free Cardston quote. More on Rim Joist Spray Foam Insulation Alberta province-wide.