Basement walls
Foam goes between the studs against the concrete, or directly on the wall before framing. It takes away the cold, damp feel of bare concrete and keeps basement moisture off the framing.
Insulation / Attics & retrofits
Basement and rim joist insulation in Edmonton and Calgary
Closed cell spray foam on rim joists, basement walls and crawlspaces. It seals the leakiest spot in most Alberta basements and stops the frost that builds up behind poly and batts.
Rim joists, closed cell
What it is
Foam where the house meets the foundation
Rim joist insulation seals and insulates the band of framing that sits on top of your foundation walls, where the floor joists end. Aires sprays closed cell foam on rim joists, basement walls and crawlspaces in Edmonton, Calgary and across Alberta.
Go downstairs and look at the top of your basement wall. That strip of wood running around the perimeter, between the concrete and the main floor, is the rim joist. In most houses it's covered by a chunk of pink batt stuffed between each joist, maybe with some poly stapled over it. That's the weak spot.
This work sits under our insulation services, and it's one of the jobs where we'd recommend spray foam over anything else.
The problem
Why rim joists leak so badly
The rim joist is an inch and a half of lumber with sheathing and siding outside it. The sill plate under it sits on concrete that's never perfectly flat. Wiring, gas lines, dryer vents and hose bibs pass through it. Every joist bay is a separate little box with its own gaps.
That adds up to a lot of air leakage around the whole perimeter of the house, right at floor level. In a lot of Alberta houses it's the worst leak in the building. It's why the main floor feels cold along the outside walls in February.
Frost behind the poly
When a rim joist has batts and poly, warm basement air still finds its way around the edges of the poly and into the batt. It hits the cold wood and condenses. In a deep cold snap it freezes. Pull back the poly in January on many Edmonton houses and you'll find frost on the rim board, then water stains and mould on the sill plate by spring.
The fix
Why closed cell foam works here
The rim joist needs insulation, an air seal and a vapour barrier, all fitted into small, awkward boxes. Closed cell does all three.
- Bonds to the wood and concrete, sealing the gap at the sill plate
- Fills around wires, pipes and vent ducts that pass through
- Roughly R-6 to R-7 per inch, about double fibreglass at the same thickness
- At 2 inches or more, no separate vapour barrier needed in most assemblies
- Resists moisture, so mould has less to grow on
- Not a food or nesting source for mice
- Lasts 50+ years without settling or sagging
- Usually done in a day
More on the material itself is on our closed cell spray foam page.
Customer
Rim joists in a new property
From a review left for Aires, word for word.
I recently hired Aires spray foam to do some rim joist in my new property, and I was extremely satisfied with their service. The job was done very thoroughly and completed on time.
Beyond the rim
Basement walls, crawlspaces and finishing
Rim joists and the walls below them can be sprayed in the same visit.
Crawlspaces
Crawlspace walls and rim joists get the same treatment. Foam handles the damp better than batts, which tend to sag and collect moisture down there.
Finishing afterwards
Once the foam cures, your framer, electrician and drywaller can carry on. In a living space, building code usually requires a thermal barrier such as drywall over the foam.
CEIP
Financing basement insulation in Edmonton
Aires is a CEIP Qualified Contractor in Edmonton and surrounding approved municipalities. Basement and crawlspace walls qualify when you add at least R-12. With closed cell foam, that takes roughly 2 inches.
CEIP needs at least three qualifying upgrades on a home unless you're going to net zero. Basement walls plus an attic top-up to R-50 cover two of them. Repayment goes on your property tax bill for as long as 25 years. The full steps are on our CEIP financing page.
CEIP is not available through Aires in Calgary, but our Calgary team still handles rim joist and basement work there.
R-12added, CEIP basement threshold
R-6+per inch, closed cell
2 inclosed cell, no separate vapour barrier
Related services
InsulationSpray foam insulationClosed cell spray foamOpen cell spray foamResidential spray foamCommercial spray foamAgricultural spray foamIndustrial & pipeline foamSea-can & van insulationAttic insulationBlown-in fibreglass & celluloseInsulation removalAttic venting & vapour barrierSoundproofing insulation
FAQ
Questions we get asked
Is spray foam worth it on rim joists?
For most Alberta basements, yes. The rim joist is one of the leakiest spots in a house, and closed cell foam seals the air leaks and insulates in one pass. Batts can't seal the gaps between the sill plate and foundation.
Do I need a vapour barrier over spray foam in the basement?
Closed cell foam at 2 inches or more removes the need for a separate vapour barrier in most assemblies. Your local building inspector has the final say on what your project needs.
How long does rim joist spray foam take?
Most of our spray foam jobs are finished in one day, and rim joists on a typical house usually fit in that. Full basement walls add time depending on the area.
Can I finish my basement right after spray foam?
Yes. Once the foam has cured, framing, electrical and drywall can carry on. Building code usually calls for a thermal barrier such as drywall over exposed foam in a living space.
Does CEIP cover basement insulation?
Yes, in Edmonton and other participating municipalities. Basement and crawlspace walls need at least R-12 added to qualify, and the home needs at least three qualifying upgrades in total.
Get a free quote
Tell us what you're insulating and where. We'll book a walkthrough, measure it, and send you a written quote. Serving Edmonton, Calgary and across Alberta.
Call or text(780) 916-7131Request a quote