CertainTeed. CertaSpray polyurethane foam insulation is now GreenGuard certified for indoor air quality. When applied, the closed-cell foam insulation expands to fill openings that could potentially leak air. By reducing air leakage, CertaSpray minimizes hot and cold spots, and penetration of moisture and outdoor allergens. The foam offers an R-value of 6.4 per inch when applied in a thickness of more than 2 inches. CertaSpray can be used in whole-house applications or in combination with fiberglass insulation, and is ideal for hard-to-reach areas such as cathedral ceilings and knee walls. 800.233.8990. www.certainteed.com.