Spray foam insulation costs in London, Ontario are driven primarily by what you're insulating — not some arbitrary per-square-foot rate. A rim joist job costs far less than a full attic conversion. This guide breaks down pricing by application, explains what drives costs up or down in London's specific housing market, and shows you how Ontario rebates affect the real out-of-pocket numbers.
Closed cell, 2–3 inches. Typical London bungalow or two-storey. Rebate-eligible.
2–3 inches closed cell on full basement perimeter. Addresses moisture and thermal issues.
Open cell on attic floor framing and penetrations. Highest impact in older homes.
Conditioned attic assembly with closed cell on roof deck. New construction or deep retrofit.
Walls and roof deck for workshop or EV charging use. Closed cell preferred.
Full building envelope spray foam as primary insulation and air barrier. Eliminates separate housewrap in many assemblies.
London's housing stock creates some specific cost variables that matter when getting a spray foam quote:
Homes built before 1960 — a significant share in Old East Village, Wortley Village, and parts of south London — often have little to no existing insulation in basement walls or rim joists. This means spray foam is being applied to completely uninsulated surfaces, which is the easiest (and most cost-effective) application. There's no removal, no tearout, just clean application to bare surfaces.
Homes from the 1970s–1990s often have fibreglass batt installed in basement walls that's degraded, fallen down, or has moisture damage. Removing this before spray foam adds $200–$500 in labour depending on the extent.
Spray foam is priced in board-feet (1 board-foot = 1 square foot at 1 inch thick). Typical London market rates:
| Product Type | Price Per Board-Foot | R-Value Per Inch |
|---|---|---|
| Open cell spray foam | $0.35 – $0.65/board-ft | R-3.5 to R-4 |
| Closed cell spray foam | $1.00 – $1.50/board-ft | R-6 to R-7 |
These materials costs alone don't tell the full story — labour, rig mobilization, masking and protection, and cleanup are all included in a complete quote. Don't compare materials-only pricing to full-service pricing.
Hard-to-access areas cost more. A London home where the spray foam rig can park close, the basement is open and clear, and the rim joists are accessible without moving mechanicals = fast job = lower cost. A cramped older home where every square foot involves moving obstacles costs more per board-foot of installed foam.
Two programs are currently active for London homeowners:
| Program | Value for Insulation | Status (2026) |
|---|---|---|
| Enbridge Home Efficiency Rebate Plus (HER+) | Up to $2,000 for insulation upgrades (project-dependent) | Active — requires pre and post energy assessment |
| Canada Greener Homes Loan | Interest-free loan up to $40,000 | Active — covers spray foam + other eligible upgrades |
Important: The Canada Greener Homes Grant closed in February 2024. The Loan program (interest-free, up to $40,000) is still active and is a valuable financing tool for larger projects like full basement walls. These are separate programs — don't confuse them.
For most London homeowners, the ROI calculation on rim joists is particularly compelling:
The math gets better when Enbridge HER+ rebates apply. A $1,000 rim joist job with a $250 rebate costs $750 out of pocket. At $250/year savings, that's a 3-year payback.
Basement wall insulation has a longer payback (8–15 years) but adds a vapour management function, addresses condensation issues, and often eliminates musty basement odours — a quality-of-life benefit the payback calculation doesn't capture.
London's housing stock and climate create above-average benefits for spray foam:
Tell us what you want insulated and we'll give you an itemized number — no surprises. Rebate eligibility check included at no charge.
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