Quick Answer: Spray foam insulation typically runs $0.50 to $2.00 per board foot as of 2026, with the spread driven by type, thickness, and whether you price material only or material and install together. Open cell sits at the low end, closed cell sits at the high end, and high density closed cell for continuous insulation sits at the top. Prices move with the chemical index, region, and contractor volume, so treat the range as a planning number and pull live quotes for bid day.
What Drives the Price
Six variables move the price of spray foam, and you should read them off the insulation schedule before you quote.
- Open cell versus closed cell. Open cell is lighter, cheaper, and expands more, so you get more coverage per kit but a lower R per inch. Closed cell is denser, costs more per board foot, and acts as an air and vapor barrier at thickness. Closed cell commonly runs two to three times the open cell price per board foot.
- Thickness and lift. Spray foam is priced per board foot, which is one square foot at one inch thick. A 2 inch closed cell application is double the board feet of a 1 inch application, and the price scales linearly with thickness. Closed cell is sprayed in lifts of 2 inches or less to avoid off gassing and shrinkage, so a 6 inch application is three lifts, not one.
- R value per inch. Open cell runs about R 3.7 per inch. Closed cell runs about R 6.5 to R 7 per inch. Higher R per inch means you hit code with less thickness, which is why closed cell is priced at a premium for the same cavity fill.
- Density and grade. Standard closed cell is around 2 pound density. High density roofing foam runs 2.5 to 3 pound and carries a premium. Open cell is typically half pound density. Density drives yield per kit and price per board foot.
- Material only versus installed. Spray foam is a contractor applied product, not a DIY commodity. The material only price per board foot is the lower number. The installed price includes the rig, the crew, the prep, and the cleanup, and commonly runs double the material only number. Estimators who bid material only on a foam job lose the gap.
- Region and volume. Foam contractors cluster in markets with enough volume to keep the rig running, so remote jobs pay travel and per diem. Volume on a tract of homes gets a better per board foot price than a single custom home, because the rig and crew are already on site.
Typical Price Ranges by Type
These are contractor price ranges as of 2026, per board foot, material only unless noted. Your local market will move the numbers, so use them to frame the bid and refresh on quote day.
- Open cell, 5.5 inch wall fill, material only: $0.50 to $0.80 per board foot. Common in walls and attic decks.
- Open cell, installed: $1.00 to $1.50 per board foot. Crew, rig, and prep included.
- Closed cell, 2 inch wall, material only: $1.00 to $1.50 per board foot. Vapor barrier and air barrier in the cavity.
- Closed cell, installed: $1.50 to $2.50 per board foot. The most common installed spec.
- Closed cell, 3 inch attic deck, installed: $2.00 to $3.00 per board foot. High R attic, no venting.
- High density closed cell, roofing foam: $2.00 to $3.50 per board foot. Roof recover, waterproof.
- Closed cell, continuous insulation, exterior: $1.50 to $2.50 per board foot. Commercial CI assembly.
Price the type the schedule calls for. An open cell bid priced as closed cell will look cheaper and lose the job when the vapor barrier is missing at inspection, because the inspector reads the schedule, not the plan view.
How to Calculate the Quantity You Need
Board feet equal square feet multiplied by thickness in inches. Take the insulated square footage from the wall, ceiling, or roof assembly, then multiply by the foam thickness in the notes. A 1,000 square foot wall at 2 inches of closed cell is 2,000 board feet, and that is the line you price.
For each assembly, note the type, the thickness, and whether it is open or closed cell. A wall at 5.5 inches of open cell is a different line than a wall at 2 inches of closed cell, even though both fill the same cavity, and you price them separate. Apply a 5 percent waste factor to the board foot count, because foam overspray, lift variation, and trim waste add up, and a tight waste factor beats a generous one when the unit price is high.
Round the count to the contractor quote, because foam is priced by the application, not by the bag. Tie every count to the sheet and assembly it came from so the bid is defensible in review.
How to Buy Smarter
- Pull three contractor quotes on bid day. Foam contractor pricing on the same spec can vary 15 to 30 percent between rigs. The type and thickness are the leveler, quote the same spec everywhere.
- Buy by the application, not the kit. A tract of homes quoted as a single application beats per home quotes, because the rig and crew are already on site. Ask for the volume break up front.
- Lock the quote for 30 to 60 days. Foam is chemical driven, and the index moves with oil and resin. A 30 day hold protects a longer bid cycle.
- Match the type to the assembly. Closed cell goes where a vapor barrier and air barrier are needed, open cell goes where fill and sound matter more. Read the notes before you price the type.
- Check the lift and the cure time. Closed cell sprayed too thick in one lift will off gas and shrink, and the fix is expensive. Price the application in the lifts the schedule calls for, not a single pass.
Where Estimators Get It Wrong
The classic mistake is pricing material only on a foam job. Spray foam is a contractor applied product, and the rig, crew, and prep are part of the cost. Material only on a closed cell job will look half the real number and lose the bid when the trim out comes in.
The second mistake is confusing open cell and closed cell. They are different products with different R per inch, different vapor performance, and different prices. Priced wrong, the bid is off by 100 percent on that line and the takeoff looks sloppy in review.
The third is forgetting the prep and the cleanup. Foam does not go over a dirty cavity, and the framing has to be dry and ready. Prep labor and masking are part of the application, and they are easy to miss on a fast takeoff. Build them into the line, not the labor line.
Putting It Together
Read the insulation notes, take the square footage by assembly, multiply by thickness for board feet, and apply the 5 percent waste factor. Price each line by type and thickness with the matching contractor quote. Get three quotes on bid day, lock them for the bid window, and price the installed number, not the material only. A closed cell wall priced at $1.20 per board foot material only becomes a $2.00 line installed, and the estimator who prices only the bucket loses that gap. Keep the count tied to the sheet, keep the quotes dated, and the bid holds up in review.