Spray foam is only as good as the crew that sprays it. The same product can seal and insulate a house beautifully or leave gaps, shrinkage and a smell that lingers, depending on how it is mixed and applied. Because the chemicals react on site, you are really hiring the installer’s skill, not just buying a material. These questions will help you sort the pros from the rest before you sign anything.

1. Are you licensed and insured, and can I see proof?

The U.S. EPA’s advice to homeowners starts here: verify the contractor’s insurance and licenses, and check their references. Licensing rules for insulation work vary by state and city, so ask what your area requires and get the license number in writing. Ask for a certificate of insurance showing general liability and workers’ compensation, and call the insurer if anything looks off.

2. Who will actually spray the foam, and what training do they have?

The company owner who gives you the quote may not be the person holding the gun. Ask who the lead installer will be and how they were trained. EPA says to make sure your contractor has received appropriate training, and OSHA requires that spray foam workers be trained on the hazards and safe work practices.

The industry’s main credential is the Spray Polyurethane Foam Alliance’s Professional Certification Program (PCP). It has four levels for insulation: Assistant, Installer (at least 100,000 board feet of spraying experience), Master Installer (at least 500,000 board feet plus an over-the-shoulder field exam) and Project Manager (has managed at least 500,000 board feet of projects). A crew led by a PCP Master Installer or Project Manager is a good sign. Certification isn’t required everywhere, so it’s a plus rather than a deal-breaker, but a contractor should be able to explain how their sprayers were trained.

3. Which product will you use, open cell or closed cell, and why?

A good contractor will name the exact product and brand and explain why it fits your project. Open cell and closed cell behave very differently with moisture, R-value per inch and price. See our guide on open cell vs closed cell spray foam. Ask for the product’s data sheet and safety data sheet (SDS). EPA and the Consumer Product Safety Commission both suggest getting copies of the product literature before the job.

4. How many inches, and what R-value will I end up with?

Quotes that only list square footage are hard to compare. Ask for the thickness in inches and the R-value that thickness reaches. Two bids can look far apart on price simply because one is for 3 inches and the other for 6. Our spray foam thickness chart shows how many inches each R-value target takes.

5. Where exactly will the foam go?

For attics in particular, the big decision is whether to foam the roof deck (making the attic part of the house) or the attic floor. It changes the price and how your HVAC works. Our attic insulation guide walks through when each one makes sense. A contractor who doesn’t ask about your ductwork and HVAC location before quoting an attic job hasn’t looked closely enough.

6. How long do we need to stay out of the house?

This is the question homeowners most often forget. EPA says occupants, including pets, should leave during installation and stay out until the foam has cured, the area has been ventilated and the space has been cleaned. Some manufacturers recommend 24 hours for the common two-component professional systems, but the time varies by product and job. Get the re-entry time for your specific product in writing before work starts.

7. How will you ventilate and protect the rest of the house?

Ask how they will isolate the work area, how they will ventilate it during and after spraying, and what they will cover or seal off. EPA’s own checklist for homeowners includes exactly these questions, plus what to expect at each stage of the job.

8. Is the weather right for spraying?

Spray foam is sensitive to temperature and humidity at the time it’s applied. EPA suggests asking what time of year is best to install in your area and what weather could affect the job. A pro will check surface temperature and moisture and should be willing to reschedule rather than spray in bad conditions.

9. What does the warranty cover, and who backs it?

Ask whether there is a labor warranty from the contractor, a material warranty from the manufacturer, or both, and get both in writing. Ask what happens if the foam pulls away from framing or shrinks.

10. Can I talk to two or three recent customers?

References from jobs like yours, done in the last year or so, tell you more than any brochure. Ask them whether the crew showed up when promised, cleaned up and handled any smell or touch-up issues.

Red flags to walk away from

  • No written quote, or a quote with no thickness, R-value or product name.
  • Pressure to sign today or a large cash deposit before any work is scheduled.
  • “You don’t need to leave the house.” EPA’s guidance is that occupants should leave during spraying and stay out until it has cured and been ventilated.
  • Can’t show a license or insurance certificate when asked.
  • Won’t name the product or provide its safety data sheet.
  • No questions about your house. A pro asks about moisture, ventilation, HVAC and what you’re trying to fix before giving a price.

If something goes wrong

EPA advises that if you have concerns after an installation, start with the contractor. If they don’t resolve it, contact your local or state consumer protection office or the contractors’ licensing board. You can also file a report with the Consumer Product Safety Commission at SaferProducts.gov.

Get more than one quote

Comparing two or three quotes side by side, with the same thickness and R-value on each, is the easiest way to see who is pricing fairly. Find spray foam insulation contractors near you and compare their reviews before you call.