About R-6 to 6.5 per inch, an air-and-moisture barrier, and rigid enough to add strength — the foam for metal buildings, crawl spaces, and tight cavities.
Tell us what the space is doing and we’ll come take a look — no charge, no pressure.
Closed-cell spray foam is the heavy hitter of the insulation world: dense, rigid, and doing three jobs at once. At about R-6 to 6.5 per inch it packs the most R-value into the least thickness, it forms an air and moisture barrier, and it’s stiff enough to add structural rigidity. When a project needs moisture control or maximum performance in a tight cavity, this is the foam we reach for.
The name describes the foam’s microscopic structure: its cells are closed and packed tight, filled with a gas that gives the foam its high insulating value and rigidity. That density is why closed-cell performs the way it does — it doesn’t let air or water vapor move through it. Manufacturer and building-science references put closed-cell in the R-6 to 6.5 per inch range, well above open-cell’s roughly R-3.7. In a tight rafter bay or a shallow wall cavity where you can’t fit much thickness, that difference decides whether you hit your target R-value at all.
Closed-cell costs more per board foot than open-cell, because you’re using a denser material and often applying it in thinner but higher-performing lifts. It’s not automatically the right choice for every job — a big open attic that mainly needs an air seal and coverage is often better and more affordably served by open-cell. The skill is matching the foam to the problem, and we’ll tell you honestly when your project doesn’t need the premium product. See our open-cell page for the other side of that decision.
Free on-site spray foam estimates across Wichita Falls and Wichita County. We’ll tell you where your building is leaking air and heat, and exactly what it takes to seal it.