Spray foam is the most expensive insulation we install, and it’s the right call surprisingly often — but not everywhere.
Most contractor pages will tell you spray foam is superior, full stop. It isn’t that simple. There are parts of a Richmond Hill home where foam solves a problem nothing else can, and there are parts where you’d be paying two to three times as much for a result blown-in gives you for less.
Here’s the honest version.
What spray foam actually does differently
Every insulation material slows heat transfer. That’s the R-value.
Spray foam does something the others don’t: it stops air movement.
Two liquid components mix at the tip of the gun and expand on contact, filling the cavity and adhering to every surface. There’s no gap between the insulation and the framing, because the insulation is bonded to the framing.
That matters because air leakage — not conduction — is responsible for a large share of the heat loss in most older houses. Batts stuffed into a wall cavity leave gaps at every edge, every wire, every outlet box. Air moves through those gaps. Foam doesn’t leave them.
The trade-off: spray foam costs significantly more per square foot than blown-in or batt, it’s permanent, and it requires professional application. It’s a specialist tool. Use it where air sealing and moisture control are the actual problem.
Open-cell vs closed-cell: the difference that determines your quote
These are two genuinely different products with different jobs. Any contractor who doesn’t explain which one they’re quoting is not giving you enough information to compare.
| ½ lb open-cell (low density) | 2 lb closed-cell (high density) | |
|---|---|---|
| Approx. R-value per inch | ~R-3.5 – R-3.8 | ~R-6.0 – R-7.0 |
| Structure | Soft, spongy, flexible | Rigid, dense |
| Expansion | High — fills large cavities cheaply | Low — controlled |
| Vapour barrier? | No | Yes, at sufficient thickness |
| Water resistance | Absorbs water | Resists water |
| Sound dampening | Better | Poorer |
| Cost per board foot | Lower | Higher |
| Best for | Interior walls, sound control, large cavities above grade | Basements, crawlspaces, rim joists, garage ceilings, anywhere moisture is a factor |
The short rule: if the assembly is below grade, touches the ground, or has cold air on the other side of it, you want closed-cell. If it’s an interior partition and the goal is quiet, open-cell does the job for less.
½ lb low-density spray foam → · 2 lb high-density spray foam →
Where spray foam is worth it in a Richmond Hill home
These are the applications where we recommend it without hesitation.
1. The cold room above the attached garage
This is the single most common comfort complaint we hear in Richmond Hill, and it’s the clearest case for spray foam anywhere in the house.
Builders typically install fibreglass batts in the garage ceiling. Batts don’t air seal. Cold garage air moves around and through them, and the floor of the room above stays cold no matter how high you set the thermostat.
The real fix: remove the garage drywall, remove the old batts, spray closed-cell foam into the joist cavities, re-drywall with 5/8″ fire-rated board. It’s more invasive than homeowners expect, and it’s the only approach that reliably works. Adding a space heater or laying more batts on top does not.
2. Rim joists and headers
The rim joist is the band of wood around the perimeter of your basement ceiling where the floor framing meets the foundation. It’s a notorious leak point in almost every house, and it’s usually stuffed with a scrap of fibreglass that does nothing.
Closed-cell foam here is inexpensive relative to the impact — small area, big result on basement comfort and draftiness.
3. Basement walls and crawlspaces
Below-grade walls need insulation and moisture control. Closed-cell foam delivers both in one application, and it won’t grow mould if the foundation weeps.
Framing a basement wall and filling it with batts, without a proper air and vapour strategy, is how you end up with mould behind the drywall three winters later.
4. Cathedral ceilings and vaulted ceilings
There’s very little cavity depth in a cathedral ceiling. When you only have 7 or 9 inches to work with, R-per-inch is everything — and closed-cell foam at ~R-6 to R-7 per inch gets you far more thermal performance in that space than anything else.
5. Renovations with open walls
If the drywall is already off, the cost of upgrading the cavity is at its lowest it will ever be. This is the moment to make the decision.
Where spray foam usually isn’t worth it
Just as important.
A standard flat attic with plenty of clearance
If you have a truss attic with 18+ inches of headroom and clear access, blown-in cellulose or fibreglass will get you to R-60 for substantially less money than spray foam. The attic floor is easy to access, and depth is cheap up there.
Spray foam applied to the underside of the roof deck creates a conditioned attic — a legitimate strategy with real advantages, particularly if you have HVAC equipment or ducting in the attic. But it is a significantly larger investment, and for most Richmond Hill homes with the equipment in the basement, blown-in to R-60 is the better value.
We install both. We’ll tell you which one your house actually needs.
Filling a wall cavity you can access easily and cheaply another way
If the walls are open and moisture isn’t a concern, batts plus proper air sealing can be a reasonable alternative at lower cost. Foam is better — but “better” and “worth the difference” aren’t the same question.
As a fix for a problem that isn’t insulation
If your upstairs is hot in summer because of undersized ductwork or a failing AC, spray foam won’t fix it. If you have ice dams caused by blocked soffit vents, foam won’t fix that either — the ventilation will.
A good assessment identifies the actual cause first. Be sceptical of anyone who arrives with one product and finds a reason to use it in every room.
Practical questions homeowners ask before booking
Do I have to move out? No. We install Insulthane Extreme by Elastochem and residents can remain in the home. That said, we’ll discuss ventilation and re-entry timing for the specific areas being sprayed, and if anyone in the household has significant respiratory sensitivities, tell us up front and we’ll plan around it.
Does spray foam need a separate vapour barrier? Closed-cell foam acts as its own vapour barrier at sufficient thickness. Open-cell generally does not, and may require a separate vapour barrier depending on the assembly and location. This is an assembly-specific question — we’ll specify it on your quote. Vapour barrier installation →
Can spray foam be removed later? Not easily. It bonds permanently to the substrate. Removal means mechanical scraping and is expensive. This is a reason to be certain about the application before committing.
Is it safe once cured? Once fully cured, spray foam is inert. The cure window is the period that requires management, which is why professional installation with proper ventilation matters and DIY kits are a poor idea for anything beyond small gaps.
Does spray foam qualify for the Ontario insulation rebate? Rebates under the Home Renovation Savings program are based on the R-value increase achieved and the area covered, not on which material you choose. Spray foam can qualify where it meets the program’s R-value thresholds for that part of the house. Note that the rebate is capped at a percentage of your project cost, which changes the math on a higher-cost material. Read the rebate breakdown →
⚠️ Program terms change. Verify current rules at homerenovationsavings.ca.
How we quote spray foam
- On-site assessment. We look at the actual assembly — basement, crawlspace, garage ceiling, attic, whatever’s in scope. No phone quotes.
- We specify the product and the thickness. Your quote states open-cell or closed-cell and the applied depth, so you can compare against other bids on the same basis. Quotes that only say “spray foam” are not comparable.
- Fixed price. Quoted from day one, no adjustments at handover.
- We tell you if foam is the wrong choice. If blown-in serves you better, that’s what we’ll recommend — we install that too.
📞 (416) 315-0471 · Book a free assessment →
