What Is Spray Foam Insulation

Spray polyurethane foam (SPF) is a two-component polymer insulation system that is applied as a liquid and expands to form a rigid or semi-rigid foam insulation layer. It is one of the highest-performance insulation materials available for building applications.

How it works: Two liquid components — isocyanate (A-side) and polyol resin blend (B-side) — are heated, pressurized, and mixed at the spray gun. The chemical reaction between the two components causes rapid expansion and curing at the point of application. The foam adheres to virtually any surface and expands to fill cavities, gaps, and irregular surfaces.

Types: Closed-cell spray foam: High density (approximately 2 lb/cubic ft), rigid foam with high R-value per inch (R-6 to R-7), excellent moisture resistance, and structural contribution. Used for walls, roofs, foundations, and applications requiring high performance in limited space.

Open-cell spray foam: Lower density (approximately 0.5 lb/cubic ft), semi-rigid foam with lower R-value per inch (R-3.5 to R-4), excellent air sealing capability, and acoustic performance. Used for interior walls, attics, crawl spaces, and sound control applications.

• Applications:
• New construction (walls, roof deck, foundation)
• Retrofit insulation (existing building enclosures)
• Metal building insulation
• Cold storage and commercial refrigeration
• Agricultural buildings
• Specialty (slab lifting, void fill, roofing)

Spray foam is manufactured at the point of application by the contractor. The quality of the installed foam depends on the equipment condition, chemical quality, operator technique, and environmental conditions during application.