Confirm the Louisiana license first. The Louisiana State Licensing Board for Contractors requires a contractor's license for any commercial project over $50,000, and a home improvement registration for residential jobs between $7,500 and $50,000 (LSLBC). Ask for the license number and confirm it is active and carries the insulation classification. A crew running a commercial spray foam job in the tens of thousands of dollars without a license is a red flag no price can offset.
Check manufacturer certification on their specific foam. Spray polyurethane foam is a two-part chemical applied on site, and every major manufacturer requires installers to complete a proprietary training program before it will sell them material. Ask which foam system the crew is certified on, whether that is the open-cell or closed-cell spray foam they plan to use on your job. Certification on the actual product going into your attic is what protects your warranty later.
Get board-foot math in the written quote. Reputable contractors price by the board foot, which is one square foot of foam at one inch thick. Open-cell runs about $0.44 to $0.65 per board foot installed; closed-cell runs $1.00 to $1.50. A quote for an attic spray foam job should show square footage, foam type, target thickness, and total board feet, not a single round number. If a bid will not break those out, you cannot compare it fairly against another.
Ask how they handle Gulf Coast humidity and moisture. Southwest Louisiana's humidity and storm exposure push most jobs toward closed-cell foam on the roof deck because it resists moisture and adds structural rigidity. A contractor who cannot explain why they are recommending open-cell versus closed-cell for your specific space, or who ignores crawl space encapsulation when your subfloor is the problem, is guessing. Local experience in this climate matters more than a low bid.
Nail down the re-occupancy and ventilation plan. Freshly applied foam needs to cure and the space needs to be ventilated before people move back in. The EPA notes that many manufacturers recommend waiting 24 hours after application before residents and other occupants re-enter, and that the area must be adequately ventilated and cleaned first (EPA). Without proper ventilation and cure time, occupants can be exposed to residual vapors and isocyanate-bearing dust (EPA). A professional crew tells you the vacate window before the job, not after.
Verify insurance and get the warranty in writing.Ask for a certificate of general liability insurance and confirm it is current. Then get the workmanship warranty on paper, separate from the manufacturer's material warranty, so you know who to call if foam pulls away from the deck or a cold spot shows up two winters later.