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Insulation Cost in Ontario (2026): The Master Price Table for Attic, Walls, Basement, Spray Foam, Batts, Removal and Air Sealing, With Three Houses Worked Through
Insulation & Air Sealing
What Insulation Costs in Ontario: One Table, Every Surface, and Three Houses Added Up So You Can See Where the Money Lands
Insulation is priced by the square foot of whatever it covers, which sounds simple until the quote arrives and the attic is in square feet, the foam is in board feet, the rim joist is in linear feet and the air sealing is a lump sum. This page puts every surface on one table at the installed rates I see around Simcoe County in October 2026, then adds up three real-sized jobs: an attic top-up on a 1975 bungalow, a basement on a 1995 two-storey, and the whole insulation package on a 2,000 sq ft new house. The numbers are before HST.
The numbers
$2.60attic top-up R-20 to R-60, per sq ft
$1.25closed-cell spray foam, per board foot
$9.60finished basement wall, Assembly A, per sq ft
$2,400whole-house air sealing, 2,000 sq ft house
| Surface and product | Unit | Range | Default |
|---|---|---|---|
| Attic top-up, blown cellulose over dry existing | sq ft of attic floor | $1.50 to $3.50 | $0.065 per R-point added, min $1.50 |
| Attic top-up, blown fibreglass | sq ft | add $0.25 | |
| Full attic from bare joists to R-60 | sq ft | $3.00 to $4.50 | $3.75 (R-50: $3.25) |
| Attic air sealing package | sq ft | $0.75 to $1.50 | $1.00, min $600 |
| Soffit baffles | per rafter bay | $3.50 | allow $300 a house |
| Hatch insulated and weatherstripped | each | $150 to $250 | $200 (box or stair cover $350) |
| Removal by vacuum truck, dry and clean | sq ft | $1.50 to $3.50 | $2.00 (rodent +$1.00, fog $300) |
| Closed-cell spray foam | board foot | $1.00 to $1.50 | $1.25 |
| Open-cell spray foam | board foot | $0.90 to $1.20 | $1.05 |
| Rim joist, 2 in. closed cell | linear foot | $4 to $7 | $5.50 |
| Spray foam minimum or mobilization | per job | $900 to $1,500 | plus masking $300 |
| Fibreglass batt R-22 in a 2×6 wall | sq ft of wall | $1.25 to $1.75 | $1.50 (R-14: $1.10) |
| Mineral wool batt R-22 | sq ft | $2.00 to $2.75 | $2.40 (R-14: $1.80) |
| 6 mil poly, sealed and taped | sq ft | $0.50 | smart retarder $0.90 |
| Dense-pack cellulose into a closed wall | sq ft | $2.50 to $4.00 | $3.25 plus patching |
| Basement Assembly A: 2 in. XPS, 2×4 wall, R-14, poly | sq ft of wall | $9.60, about R-21 | |
| Basement Assembly B: 3 in. closed cell, 2×4 wall | sq ft | $8.75, R-19 to R-21 | |
| Under-slab 2 in. EPS with poly, before the pour | sq ft of slab | $1.75 to $2.25 | $2.00 |
| Whole-house air sealing package | per house | $1,500 to $3,500 | $2,400 |
| Blower door test, standalone | each | $300 to $450 | in an EnerGuide evaluation $500 to $800 |
Every attic line is in the attic insulation cost calculator. The foam and batt lines are worked surface by surface in the materials section, and the four basement assemblies in the basement section. Minimum attic job $900.
What moves the price
Access first. A walk-in attic with a hatch in the hall is the default rate; a 1960s bungalow with 14 in. of headroom at the eaves and two hatches in closets costs more because a man on his belly blows half as much an hour. The same goes for a basement with forty years of shelving against the walls.
Minimums second. A spray foam crew is two men, a truck and a rig, and they are not driving to Penetang for 400 sq ft of wall. Expect $900 to $1,500 for the smallest job; if all you need is the rim joists, bundle them with the garage ceiling so the trip pays for itself. Masking is extra: $300 of plastic is the difference between foam on the wall and foam on the window.
Removal third. Blowing over dry, clean, flat old insulation is normal and the top-up rate assumes it. Blowing over wet, mouldy or rodent-soaked insulation is not done, by me or anyone I would hire; it comes out first at $2.00 a square foot and up, and if the attic has vermiculite nobody touches anything until a lab result comes back.
Three houses worked through
House one: a 1975 bungalow in Midland, 1,200 sq ft attic at R-20, going to R-60. Top-up, 40 R-points at $0.065 is $2.60 a square foot, 1,200 at $2.60 is $3,120. Air sealing the attic plane before the blow, 1,200 at $1.00, $1,200. Baffles at every soffit bay, $300. The hatch insulated and weatherstripped, $200. Subtotal $4,820, HST $627, total $5,447. If the house qualifies for the standalone attic rebate, which depends on who does the work and what the attic was at, up to $1,000 can come back afterward; the rebate page has the conditions and I do not subtract it here because nothing is subtracted until the cheque clears.
House two: a 1995 two-storey in Barrie, 36 by 28 ft, finishing the basement. Perimeter 128 ft by 8 ft is 1,024 sq ft of wall, less 40 sq ft of windows, 984 sq ft. Assembly A, the XPS-and-stud-wall that most contractors build, 984 at $9.60 is $9,446. Rim joists in 2 in. closed cell, 128 lf at $5.50, $704. Subtotal $10,150, HST $1,320, total $11,470. Assembly B, 3 in. of closed cell on the concrete with the stud wall in front and no poly, is 984 at $8.75, $8,610, plus the same rim, $9,314 before HST. That is about $840 under A, and B is the better air seal as well, which is why it is the one I would pick when the crew can get at the walls.
House three: a 2,000 sq ft two-storey, new, conventional frame. 2,400 sq ft of net wall in R-22 batts with sealed poly at $2.00, $4,800. Attic, 1,100 sq ft blown to R-60 from bare joists at $3.75, $4,125. Basement at Assembly A, $9,446, and rim, $704. Under-slab foam and poly, 1,000 sq ft at $2.00, $2,000. The whole-house air sealing package, $2,400. Total $23,475 before HST. The same house in ICF has the walls and the basement inside the ICF price and needs $7,325 of separate insulation work, which the new home insulation page takes apart.
Where the money goes first
If the budget does not cover the whole list, the order is the same on almost every house I look at. Air sealing before anything, because fibreglass does not stop air any more than a sweater stops wind, and blowing R-40 over a leaky ceiling buries the leaks where nobody can reach them again. The attic next, because it is the cheapest R on the house. The rim joist third, 128 ft of 1.5 in. lumber with a draft behind it. The basement walls fourth. Above-grade walls last, because getting insulation into a closed wall costs $3.25 a square foot plus the patching, and the walls were never the biggest loser.
Rule of thumb: a blower door test before and after, $300 to $450 on its own, tells you whether the $2,400 of air sealing did anything.
Where homeowners go wrong
- Paying per square foot without knowing the starting R. A $2.60 top-up and a $1.30 top-up are both correct; one takes the attic from R-20 and the other from R-30. Measure the depth before anyone quotes.
- Letting the quote skip the air sealing line. If it is not listed, it is not happening. $1.00 a square foot of the attic, minimum $600, as its own line.
- Insulating over a problem. Wet insulation, a bath fan dumping into the attic, knob-and-tube wiring, non-IC pot lights, a chimney without its 3 in. clearance. Every one of these is fixed before the truck comes, not covered by it. Insulation does not touch knob-and-tube; the Electrical Safety Code does not allow it and your insurer will not either.
- Buying the smallest spray foam job on its own. The $900 minimum on 200 sq ft of rim is $4.50 a square foot of foam that costs $2.50 when the crew is already there.
- Tightening the house and forgetting it breathes. After the air sealing, the bath fans, the range hood, the furnace and the water heater all share less air. Have the ventilation looked at the same month.
Questions people ask
How much does it cost to insulate an attic in Ontario?
For a top-up over dry existing insulation, $1.50 to $3.50 a square foot of attic floor, about $2.60 to go from R-20 to R-60. With air sealing, baffles and the hatch, a 1,200 sq ft attic runs about $4,820 before HST, $5,447 with. From bare joists, $3.75 a square foot to R-60.
How much is spray foam insulation per square foot in Ontario?
Foam is priced per board foot, which is a square foot at 1 in. thick. Closed cell is $1.00 to $1.50, $1.25 as a fair default, so 2 in. on a wall is $2.50 a square foot and 3 in. is $3.75. Open cell is $0.90 to $1.20 a board foot. Add masking and a $900 to $1,500 minimum on a small job.
What does it cost to insulate a basement in Ontario?
About $9.60 a square foot of wall for the usual foam-board-plus-stud-wall assembly, $8.75 for spray foam plus a stud wall, including the batt and the poly where it belongs. On a 36 by 28 ft house that is $9,446 for the walls and $704 for the rim joists, $11,470 with HST.
Are these prices before or after rebates?
Before, and before HST. The only rebate that applies without an energy assessment is the attic one, and it is paid to you afterward if the house, the attic and the contractor all qualify. No quote on this site shows a rebate as money already off the price.
Price your own attic in two minutes
The attic insulation cost calculator takes the attic area, the existing depth, the target R, the product and the extras and gives you the number with HST and the rebate check on it. If you already have quotes, the $99 review reads up to three of them against this table and says which lines are missing and which are high.
Sources and further reading
- Keeping the Heat In: Natural Resources Canada: the plain-language Canadian guide to air sealing, insulation materials, basements, walls and ventilation.
- Ontario’s Building Code: the official page with the current regulation; vapour barriers are 9.25, attic ventilation 9.19, thermal barriers over foam 9.10.17, radon 9.13.
- CUFCA Quality Assurance Program: Canadian Urethane Foam Contractors Association: certified installers with photo ID, licensed contractors, daily work sheets and the CAN/ULC S705 standards a spray foam job is held to.
