R21 insulation is approximately 5.5 inches thick. This type of insulation is often used in walls and provides a higher R-value compared to standard insulation options, contributing to improved energy efficiency and thermal comfort in residential and commercial buildings.
R13 insulation is commonly used in exterior walls, floors, and crawl spaces where moderate insulation levels are needed.
Spray foam insulation can last 20 to 30 years or more if properly installed and maintained.