How to Read a Spray Foam Quote, Line by Line

What a spray foam quote should show

1. Each surface measured separately. Walls, gables, roof deck, rim joist, with doors and windows subtracted.
2. Thickness for each surface. In inches, not "full coverage" or "R-21 walls."
3. Board feet. Area times thickness, for each line and in total.
4. Product name and type. The manufacturer and the exact product, and whether it's closed-cell or open-cell. "Closed-cell foam" on its own isn't a product.
5. R-value. Thickness times the product's aged R-value per inch.
6. Prep and cleanup. Masking, floor and window protection, trimming, debris removal.
7. Thermal or ignition barrier. Included, excluded or not required, and why.
8. Warranty in writing. Product and workmanship, with the length stated.
9. Schedule. Start window, days on site and when you can go back in.
10. Exclusions. Removal of old insulation, electrical, drywall, trip charges, change orders.

Check the math in two minutes

1. For each line, multiply square feet by inches. Write down the board feet.
2. Add the lines.
3. Divide the total price by the total board feet. That's your price per board foot.
4. Multiply each thickness by the product's R-value per inch. If it doesn't match the quote, ask why.
5. Repeat for the other quote.

Example: 1,279 square feet of wall at 2.0 inches is 2,558 board feet. If the product's data sheet lists R-7 per inch at that thickness, that's R-14. A $4,860 price works out to $1.90 per board foot. For typical ranges, see what spray foam insulation costs.

Thickness: minimum or average?

Sprayed foam is applied in passes, and thickness varies a little across a wall. Ask whether the number on the quote is a minimum or an average, and how the installer checks it. Pushing a depth gauge into cured foam takes seconds.

R-value: which number, and from where

Ask for the product's technical data sheet. The R-value on a quote should be the aged value tested to ASTM C518, not an initial value.

Closed-cell foams don't all carry the same rating. A 2009 DOE Building America guide used R-6.1 per inch for its closed-cell example. Evaluation reports for current HFO closed-cell products list roughly R-6.3 to R-7.5 at 1 inch, and the per-inch value can change with thickness: one product is listed at R-6.3 at 1 inch and R-30 at 4 inches. So "2 inches of closed-cell" isn't one R-value until the product is named, and the number should come from the data sheet at the thickness you're buying. Spray foam R-value per inch explains why.

You can also ask for the product's ICC-ES evaluation report. It lists the code approvals and the barrier requirements for that specific foam.

More thickness isn't always better value. Past 3 inches, each inch of closed-cell adds only 1–2 points of heat-loss reduction (see the hot-box data).

Prep, cleanup and the barrier line

Overspray travels. A quote should say what gets masked and covered, who moves stored items, and whether trimming and debris removal are included.

The barrier line is easy to miss. The International Residential Code (Section R316.4) requires foam in living space to be separated by an approved thermal barrier, typically 1/2-inch gypsum board, or by a coating the foam was tested with. Attics and crawlspaces entered only for service need an ignition barrier (R316.5.3 and R316.5.4). If a quote is silent, ask who provides it and what it costs.

Warranty, schedule and exclusions

Two warranties matter. The manufacturer's product warranty usually has to be registered by a certified installer. The installer's workmanship warranty covers the application itself. Get both in writing, with the length.

For reference, FoamGuard's coverage is the manufacturer's product warranty for the foam sprayed on your job plus A Craftsman's Promise, our 5-year craftsmanship warranty. Homeowners can look up a warranty at foam-guard.com/warranty.

Ask whether the installer records drum lot numbers. That's how a warranty claim gets traced back to the chemical that was sprayed. More in how to choose a spray foam contractor.

On the schedule, look for a start window, days on site and the re-entry time. A CPSC staff fact sheet on professional spray foam says residents should leave for at least 24 hours, and that the right time depends on the product.

Exclusions to look for: removal of old insulation, electrical work, drywall, trip charges if the site isn't ready, and how change orders are priced.

Two quotes for the same job (hypothetical)

Same building: a 30 × 40 garage with 10-foot walls, 1,279 square feet of wall after 121 square feet of doors are subtracted.

Quote A is $960 less. It also buys 639 fewer board feet, costs more per board foot, and leaves the masking and cleanup to you.

The thinner foam matters more than the price gap suggests. On the hot-box curve, 1.5 inches of closed-cell cuts heat loss about 81%, against 86% at 2 inches. And some closed-cell products don't qualify as a Class II vapor retarder until close to 2 inches, so 1.5 inches may fall short. On a cold metal wall, that margin is what keeps condensation off the panels.

Red flags on a quote

• A price per square foot with no thickness.
• An R-value with no product named.
• "Spray foam" with no type, open-cell or closed-cell.
• No written warranty, or a product warranty nobody will register.
• Pressure to sign the same day.

Want a quote you can check line by line? Price My Project or call (814) 208-3478.