The short answer
Choose a spray foam contractor by checking the whole installation process, not the sales pitch: legal identity and any required license, current insurance, who will actually spray, a moisture and substrate survey, the exact foam product and thickness, a written safety and re-entry plan, inspection and warranty terms, and an itemized all-in price. If a contractor cannot explain why their foam belongs in your roof, wall or foundation and how occupants will be protected, don't sign.
Rule of thumb: If a contractor cannot explain why their specified foam belongs in your particular roof, wall or foundation and document how occupants will be protected during installation, don’t sign. A very low quote doesn’t compensate for missing fundamentals.
The 12-point contractor scorecard
| Check | What to request | Deal-breaker |
|---|---|---|
| 1. Legal identity | Business and trading names | Unverifiable provider |
| 2. Local licensing | Required licence/status | Misrepresentation |
| 3. Insurance | Current certificates | No credible cover |
| 4. Relevant experience | Comparable jobs and references | Only unrelated project photos |
| 5. Crew qualification | Actual applicator/supervisor details | No accountable installer |
| 6. Site survey | Moisture and substrate assessment | Spray over known leaks |
| 7. Foam specification | Manufacturer and data sheet | “Our proprietary foam” with no product details |
| 8. Thickness | Minimum, R-value, verification | Generic inches without assembly target |
| 9. Building design | Air, thermal and vapor path | No condensation explanation |
| 10. Safety plan | PPE, isolation, ventilation, re-entry | Allows occupants during spray |
| 11. Closeout | Photos, warranty, cleanup | No inspection/documentation |
| 12. Comparable price | Scope, exclusions, payment terms | Vague quote or hidden costs |
Step 1: Check actual credentials
Licensing and insurance: Verify the company’s legal name and any licence required in your state or municipality. Obtain current liability and workers’ compensation evidence as applicable; never equate a website badge with coverage.
Product traceability: Ask for the manufacturer, exact foam formulation, data sheet and proposed thickness. Open-cell and closed-cell have different R-value and vapor characteristics; a generic ‘R-21 foam’ quote is not sufficient.
Site assessment: Before spraying, identify water leaks, substrate moisture, cavity access, ventilation and HVAC implications, fire-protection needs, pest access and existing insulation.
Health protection: Require a written plan for occupant/pet exclusion, work-area containment, ventilation, cleaning and product-specific re-entry instructions. EPA says it is not clear how much time is needed before re-entry is safe, and that it depends on the product[1].
Verification: Require a minimum installed depth, photographs or inspection points, material warranty conditions and specific correction obligations for voids, adhesion or off-ratio concerns.
Step 2: Insist on a building-specific recommendation
Ask why the contractor prefers foam over blown fiberglass, cellulose, mineral wool or rigid board. Some attic floors do not justify foam. Some foundations require drainage repairs before any insulation. Some roof decks demand a detailed vapor-control design.
The strongest supplier isn’t the one recommending maximum product volume; it’s the one matching the assembly to your climate, building and budget.
Step 3: Validate the spray foam product
Demand the manufacturer and exact formulation, technical data, declared aged R-value, tested air-barrier thickness, vapor permeance and substrate compatibility. Confirm the foam is listed/approved for the actual application.
An application branded simply “closed cell R-7” is not an adequate specification when thickness and whole-wall thermal bridging matter.
Step 4: Audit the application and occupant safety plan
Professional SPF installation uses reactive chemicals. EPA recommends occupant and unprotected trade-worker exclusion, PPE, controlled ventilation and product-specific cure/re-entry arrangements[2][1]. Ask for the written plan before any deposit.
A guaranteed safe return after 24 hours, regardless of product or site conditions, is a red flag. Re-entry depends on curing, cleaning and ventilation.
Step 5: Compare true all-in prices
A board foot is one square foot at one inch of foam depth. For a 700-square-foot application at three inches, theoretical usage is 2,100 board feet. That’s a quantity calculation, not an installed bid or code-compliant thickness recommendation.
Request a line-item price for site preparation, substrate repairs, demolition, masking, foam type, board-foot volume, crew minimums, access, fire protection, cleanup and restoration. If competing against blown cellulose, fiberglass or mineral wool, demand equivalent whole-assembly performance and include a separate air-sealing scope where needed.
Beware of comparing your home’s floor area to the actual surface sprayed: a roofline, walls and rim joists have different geometries. Use the spray foam cost calculator for a transparent starting estimate.
Step 6: Require inspection and warranty detail
Define acceptance criteria before the crew starts: measured areas, minimum thickness, complete sealed transitions, appropriate protective finish, cleanup and photos.
Distinguish manufacturer material warranty from installer workmanship warranty. Confirm whether corrective work includes opening/replacing finishes, independent testing or repair of concealed damage.
When to walk away
Walk away when references cannot be verified, a roof leak is ignored, the company proposes to block vents without unvented-attic design, occupant safety is minimised, product records are withheld, or a salesperson pressures you into signing before comparing scopes.
For suspected defective foam, get independent inspection before accepting an offer simply to spray over the problem.
Questions owners ask
Should I choose the cheapest quote?
No. Compare correct insulation depth, air sealing, substrate repairs, fire protection, installation safety and the complete finished scope.
What proof should I ask for?
Business/licensing records as locally applicable, insurance evidence, specific product documentation and recent verifiable references.
How many contractor quotes do I need?
Two or three comparable written proposals is a sensible starting point.
Is spray foam always better than fiberglass?
No. Fiberglass with appropriate air sealing can provide strong performance and better value on many ordinary attic floors.
Can I stay home during spraying?
Unprotected occupants should not be in the application area; follow the specific product's re-entry, ventilation and cleaning requirements.
Does the contractor need to inspect moisture first?
Yes. Foam must not be used to conceal unresolved leaks or wet sheathing/framing.
Is certification required everywhere?
No single national rule covers all local licensing and certifications. Check your jurisdiction and product/industry qualifications.
Sources
- Vacate and Safe Re-Entry Time for Spray Polyurethane Foam Application, U.S. Environmental Protection Agency (archived). Accessed October 19, 2026. Last updated September 2, 2020; archived EPA page.
- Safer Workplace Practices for Spray Polyurethane Foam Installation, U.S. Environmental Protection Agency (archived). Accessed October 19, 2026. Last updated November 5, 2020; archived EPA page. PPE, isolation and ventilation for SPF work.