Its closed-cell structure stops water and water vapor, resists compression, and holds its R-value over time. Must be protected from solvents and sunlight. Flammable and must be protected from fire with drywall or plaster.
Good for: In-ground foundation insulation, masonry structures
R-value per inch: 5
Vapor barrier needed: No
Cost: 50¢ per sq. ft. for a 2-in.-thick panel