Hiring a Spray Foam Contractor: What the Quote Must Say

The area in square feet and board feet; open-cell or closed-cell and the manufacturer; depth in inches and the resulting R-value against your climate zone's code minimum; what's being removed first and where it goes; masking and protection of wiring, lights, ducts and equipment; the ignition barrier or thermal barrier over the foam, or a note that the space is exempt; sealing of attic vents for an unvented assembly; re-entry time; a permit if required; and a warranty on adhesion and shrinkage. Get three quotes on the same spec so they compare.

Look for a company that owns its rigs and sprays foam daily rather than a general insulation contractor who subs it out. Ask whether the applicators hold SPFA (Spray Polyurethane Foam Alliance) certification or manufacturer training, and which foam system they use — the major brands publish which contractors are trained on their product. Confirm general liability and workers' comp, and ask to see a job in progress: a good crew masks meticulously, checks substrate temperature and sprays in lifts, not one thick pass.

24 hours is the common contractor and manufacturer guidance for occupants after the spray is finished, with ventilation running; EPA guidance is to follow the product's re-entry time and ventilate for at least that long. Some closed-cell products and larger jobs call for 48–72 hours. Anyone with asthma, and pets, should stay out on the longer end. Ask for the re-entry time in writing and plan to be elsewhere.

One day for the spraying on a typical 1,500 sq ft attic, plus a day beforehand if old insulation is being removed, and a return visit for the ignition-barrier coating if it's a separate step. A two-car garage is half a day; a pole barn one to two days. The crew masks and preps for as long as they spray. Then 24 hours or more before you're back in the house.

Roof deck, almost always. Foam on the roof deck creates an unvented, conditioned attic: ducts and air handlers up there are inside the envelope, and the roof's vents get sealed. Foam on the attic floor is rarely done — it's expensive per R compared with blown cellulose or fiberglass on the floor, and it can trap moisture under it. If a contractor proposes foam on the floor of a vented attic, ask why; blown-in insulation is usually the right answer there.

A price with no board feet or depth; a quote that's dramatically below others (usually thin foam or the wrong type); no mention of the ignition barrier or thermal barrier; spraying with occupants home; no substrate temperature check; a single thick pass instead of lifts; no answer on which foam system they use; and selling closed-cell on an attic roof deck in a cold climate without discussing thickness — too little closed-cell there can hold condensation against the sheathing.

Two warranties: the contractor's on workmanship (adhesion, shrinkage, gaps, missed depth — typically 1–5 years) and the manufacturer's on the material (often 10 years to lifetime, but only if applied by a trained contractor at the right thickness). Get both in writing, along with the foam system name, so a claim is possible. Ask what happens if the foam shrinks from the framing — that's a formulation or temperature failure and should be repaired at no cost.