Insulation Materials in Ontario (2026): Spray Foam Cost by the Board Foot, Foam vs Mineral Wool, Fibreglass vs Mineral Wool, EPS, XPS and Polyiso, Cellulose, Fire Barriers

Insulation & Air SealingMaterials

The Materials: What Each One Does, What Each One Costs Installed, and Where Each One Belongs So You Are Not Paying Foam Money for a Batt Job

Foam, mineral wool, fibreglass, rigid board, cellulose. Per board foot, per square foot, per R. Central Ontario, October 2026.

Every product on this page is the right answer somewhere and the expensive answer somewhere else. Closed-cell foam is unbeatable at the rim joist and on a concrete wall and a waste of money on an attic floor. Mineral wool is the batt I reach for where fire and sound matter and overkill in a ceiling nobody will hear through. Rigid board is the thermal break outside the studs and a mistake inside a basement wall with batts behind it. These pages give the cost, the R per inch and the place for each, and the ways each one is installed wrong.

Price spray foam Foam costs Foam vs wool

The numbers

$1.25per board foot, closed cell ($1.00 to $1.50); open cell $0.90 to $1.20
$1.50per sq ft, R-22 fibreglass batt installed
$2.40per sq ft, R-22 mineral wool installed
R-6per inch, closed cell; R-3.7 open cell; R-3.6 cellulose

The guides

Spray foam cost in Ontario

Board feet explained, closed vs open cell, what changes the rate, masking, backing, minimums, three jobs priced.

Spray foam vs mineral wool

Where foam wins, where wool wins, and the cost per R of each in the places they compete.

Fibreglass vs mineral wool batts

R per inch, cost, fire, sound, how each installs, and which goes where in the houses I build.

EPS, XPS and polyiso

The three boards: R per inch, moisture, cold-weather R loss, where each belongs, cost.

Spray foam installation problems

Shrinkage, off-ratio foam, odour, short thickness, no thermal barrier: how each is checked and fixed.

Cellulose insulation guide

What it is, the borate treatment, settling, dense pack vs loose fill, where it belongs, cost.

Fire and thermal barriers

What burns and what does not, the thermal barrier rule over foam, fire-rated assemblies, substitutions.

Closed cell vs open cell

Already on the site: the two foams, what each does, and where each belongs.

Four rules for choosing a material

  1. Foam where air and water are the problem; batts where they are not. Rim, concrete, cathedral slope: foam. Open stud wall with a good air barrier: batt. Foam vs wool.
  2. Buy foam by the board foot and the certification. Thickness on the quote, CUFCA card in the installer’s pocket, work sheet in your hand. What goes wrong.
  3. Cover exposed foam. Drywall or a coating, the day it is sprayed if you can. The barrier rule.
  4. A batt in a wall is only as good as the air barrier beside it. Fibreglass in a leaky wall is a sweater in the wind. Batts.

Have quotes or plans in hand? Let a builder read them first

For $99, I put your attic, spray foam, basement or air-sealing quotes on one grid, check the area and the existing R-value against your house, name the product and the depth each one actually promised, price the air sealing, baffles, hatch and removal that was left out, check the rebate claim, and tell you which one to sign. For a new build or an addition, $249 turns your plans into a whole-house insulation takeoff, attic, walls, basement, rim and slab, with the SB-12 number each assembly needs and a scope three contractors can price the same way.

Insulation quote review, $99 Insulation takeoff, $249 Check the quotes yourself first