constructionfoam

Construction foam is an expanding polyurethane material used in building to seal gaps, insulate, and improve airtightness. It is typically available as one-component aerosol products that cure on exposure to air moisture, and as two-component systems used by professionals that are mixed and sprayed or injected into cavities.

The foam is dispensed into voids and expands to fill irregular spaces, then cures to a stiff, adhesive foam. It bonds to most common construction substrates such as wood, concrete, metal, brick, and plaster. Curing is largely moisture-driven and occurs over hours, with full strength developing over 24 hours or more. The resulting seal helps reduce air leakage, improve thermal performance, and provide some acoustic damping.

Common applications include sealing around windows and doors, filling gaps around vents, pipes, and cables, insulating attic and crawl space penetrations, and sealing joints in roofs and walls. It is chosen for its high R-value per inch, rapid installation, and ability to fill hard-to-reach spaces. Limitations include potential over-expansion that can bow components, difficulties with removal once cured, and reduced effectiveness if exposed to UV light without a protective covering. It is not typically used as a structural adhesive and may require finishing with trim, paint, or additional insulation.

Safety and handling require ventilation and personal protective equipment to avoid inhalation and skin contact during application, as uncured foam can irritate. Cured foam generally poses fewer health risks, but disposal should follow local regulations for aerosol and polymer products. Standards and labeling vary by region and product type, with newer foams often aiming to reduce volatile emissions and environmental impact.