Spray Foam Questions, Answered

Open cell is lighter and more affordable per inch — excellent air sealing and sound deadening, the standard choice under a roof deck. Closed cell is denser: roughly double the R-value per inch, its own moisture barrier, and rigid enough to stiffen what it bonds to, which is why metal buildings and rim joists call for it. Most good projects use each where it belongs, and the quote will map that for your building.

In this climate, an attic retrofit is usually the single most effective envelope upgrade a house can get, because it attacks both heat gain and air leakage at once. How much shows up on the bill depends on the house, the ductwork and the AC — which is why we talk expected impact honestly at the quote instead of promising a percentage from a brochure.

Because bare steel is the worst envelope there is — it drips condensation on cool mornings, radiates heat all summer, and has no cavity for traditional insulation. Closed-cell foam bonds straight to the panel, stops the condensation at the surface, insulates hard in a couple of inches, and stiffens the shell. The barndominium movement standardized on it for good reason.

Most single-family attics are sprayed in one day; a 30x40 shop typically takes a day; full new-construction envelopes run one to two mobilizations. Foam needs a ventilated curing window before re-occupancy — typically 12 to 24 hours for the sprayed area depending on the product — and we schedule so that window lands as painlessly as possible.

Cured foam is inert — the safety window that matters is during and immediately after application, which is why the crew sprays in supplied-air protection and the space ventilates through the curing period before anyone re-occupies it. Done by the book — right temperatures, right lift thickness, right ventilation — it is a well-understood, widely inspected building product.

If foam is going on the roof deck, old insulation on the attic floor sometimes stays and sometimes must go — it depends on where the new thermal boundary lands and what condition the old material is in. Contaminated or rodent-damaged insulation should come out regardless. We quote removal and foam as one package so there is no surprise between steps.

Typical local ranges: open cell around $0.45 to $0.75 per board foot, closed cell $1.00 to $1.60. In package terms: most attic retrofits land between $3,000 and $6,500, a 30x40 shop between $3,000 and $6,000, and full custom-home envelopes from about $8,000 up. The building decides — which is why quotes are free and done from a real look, not a phone guess.

That is half our work. Foam slots between rough-in inspection and drywall on conventional builds, and after dry-in on metal shells. Send the plans and the target dates and we will return a written package, coordinate with the builder or GC directly, and photograph the finished work for the inspector.