Rim Joist Insulation
The rim joist, the band where the floor framing meets the foundation, is one of the most common and overlooked draft paths in a house. We seal it with closed-cell foam, shutting down cold air and moisture at the point most insulation never reaches.
Why homeowners choose it
- Closes one of the most common draft paths in a home
- Closed-cell foam blocks cold air and moisture together
- Pairs naturally with basement and crawl space work
What the work involves
The rim joist is the band of wood that runs around the top of the foundation, where the floor framing sits. It is where cold outside air meets the house, and it is rarely sealed. If there is insulation there at all, it is usually batts pushed into the bays, and batts slow heat without stopping air, so the draft keeps coming around them.
We spray closed-cell foam into each bay, against the rim and the sill. It seals the air path and blocks moisture in the same layer, and because it gives the highest R-value per inch of anything we install, it fits the shallow bays without building anything out.
How we install it
In-home assessment
We inspect your attic, walls, or crawl space and find exactly where your home is leaking energy.
A clear, fair quote
You get a straightforward plan and price, the right material for each space, no upsell.
Clean, expert install
Our expert crew seals the envelope, protects your home throughout, and leaves it spotless.
Questions homeowners ask
Where is the rim joist, and why does it leak?
It is the band of wood around the top of your foundation, where the floor framing meets it. It sits right where cold outside air meets the house and is rarely sealed, which makes it one of the most common draft paths in a home. Cold floors and drafts at the baseboards often start here.
Why closed-cell foam and not batts?
Closed-cell foam seals the air and blocks moisture in one layer, and it packs the most R-value into a thin space, so it suits the shallow bays at the rim. Batts slow heat but leave the air moving around them.
Does rim joist work go with other jobs?
Often. It pairs naturally with basement and crawl space insulation, and it is one of the first places we look when we air-seal a house, right after the attic. We check it during the assessment and include it in the quote if it needs work.
Where we do this
Based on Federal Road in Brookfield, working across western Connecticut and the New York border.
Best for
Basements, crawl spaces, band joists
Not sure if rim joist insulation is right for your space? We'll assess your home and recommend the material that actually fits.
Request an estimateDone properly the first time.
Request an estimate and we'll assess your home or building, specify the right material for each space, and give you a clear plan. On time, and spotless when we leave.