Closed-Cell vs. Open-Cell Spray Foam in Bismarck, ND

Closed-cell foam is dense and rigid, runs about R-6.5–7 per inch, resists water, and acts as a vapor barrier at sufficient thickness — the go-to for pole-barn shells, rim joists, crawl spaces, and below-grade or exterior-exposed applications. In a central North Dakota winter, that vapor-barrier property is a genuine advantage in cold-climate wall and roof assemblies.

Open-cell is softer, runs about R-3.6–3.8 per inch, is vapor-open, and dampens sound better — a reasonable choice for interior partition walls and attic slopes where cost matters more than maximum R-value per inch. Plenty of projects use both, and a local installer can walk the specific assembly rather than give a one-size answer.