The walkthrough happens before job day, and it sets the whole schedule. A real estimator goes into the attic, measures, and comes back with square footage, foam type, target thickness, and total board feet. Those four numbers belong on your written quote. If a bid arrives as a single lump sum with no thickness on it, you cannot tell whether you are buying a code-minimum job or a performance job. The walkthrough is also when the crew finds the things that add hours: a pull-down ladder too narrow for hose, decking that has to come up, or an air handler sitting exactly where the foam needs to go.
Prep and masking take longer than most people expect, and that is a good sign. Budget two to three hours before any foam leaves the gun. The crew masks soffit vents, covers the air handler and ductwork, tapes off anything that overspray could reach, and shuts the HVAC system down so it cannot pull vapors through the ducts into the rest of the house. Overspray cures in place and does not wipe off. A crew that walks in and starts spraying inside twenty minutes is the crew that leaves foam speckle on your shingles, your condenser, and your car.
Air sealing comes first, before any foam goes down. ENERGY STAR is direct about the order: contractors should seal air leaks in the attic floor before adding insulation, because it is much easier to seal first and it is what lets the insulation deliver its full rated performance. On an attic floor job that means the top plates, wire and pipe penetrations, the plumbing vent chase, and recessed light housings get sealed while there is still room to work. On a roof deck job the foam itself becomes the air barrier, but the same penetrations still get addressed before the passes start.
The spray goes on in lifts, not in one thick coat. Closed-cell foam is applied in passes of roughly one to two inches, and each pass has to cool before the next one goes over it. The reaction that expands the foam is exothermic, so a crew that tries to hit full thickness in a single pass traps heat in the middle of the foam. That shows up as shrinkage, poor adhesion, and in the worst cases scorching in the core. This is the single most common corner cut in the trade and it is invisible once drywall is up. Thickness is what you are actually buying: open-cell delivers about R-3.6 to R-3.8 per inch, so an R-49 attic target lands near 13 to 14 inches, while closed-cell runs about R-6.5 per inch and hits the same target at 7 to 8 inches. Lake Charles sits in Climate Zone 2, and Louisiana enforces the 2021 IECC with state amendments. Under those amendments, Table R402.1.3 of the Louisiana Energy Code sets the prescriptive ceiling minimum at R-38. So R-38 passes inspection, and R-49 is the number that actually moves an August electric bill.
The crew will be in full-face respirators and suits, and that is normal. OSHA recommends employers provide applicators a supplied-air respirator for both safety and comfort, since heat stress becomes a real issue in a Louisiana attic, and where a cartridge respirator is used it is a full-face unit with an organic vapor cartridge. Suits, gloves, and eye protection go with it. None of that says the cured foam in your attic is hazardous. It says the aerosolized chemicals during application are, which is the same reason you are standing in your driveway instead of watching from the hallway.
The vacate and re-entry window is the one rule worth being strict about. The EPA notes that some manufacturers recommend 24 hours after application for a two-component high pressure professional system before workers re-enter without PPE and before residents and other occupants move back in, and that the recommended time varies by product. So do not accept a verbal reassurance that you are fine in a couple of hours. Ask your installer for the product data sheet and get the specific re-occupancy time written on the quote before you schedule. Take pets with you, birds especially, and leave the ventilation running the way the crew sets it up.
Trimming, inspection, and the certificate close the job out. Before load-out the crew trims foam flush where it has expanded past rafters or studs, checks depth with a gauge rather than by eye, and cleans up the overspray. The Louisiana Energy Code requires a signed state insulation certificate to be attached permanently in a utility area of the house. It has a line for the area insulated, the total R-value, the installed thickness, the spray foam density in pounds per cubic foot, and whether an ignition barrier and a thermal barrier were provided, broken out row by row for the attic roofline, the attic floor, and the crawl space. Ask to see it filled out before the truck leaves. On an attic or crawl space job that certificate is your only durable record of what you actually paid for, and on a new construction job the inspector will look for it.
What to do next. Get a written quote that states square footage, foam type, target thickness, total board feet, and the manufacturer's re-occupancy time, then price it against the ranges below before you sign anything. Our Lake Charles service page covers what local jobs look like, our main page lays out the full range of spray foam work we handle across Southwest Louisiana, and you can request a written quote with your square footage and the problem you are trying to solve. A ballpark number over the phone is fine for planning. Nobody should sign one.