: Home Depot and Menards are primary sources for common brands like Owens Corning and SilveRboard .
: Websites like Insulation4US and Pexuniverse offer a wider range of densities and specific-use boards (e.g., under-slab or joist-specific). where can i buy foam insulation board
: Foil-faced boards (common in Polyiso) act as a radiant barrier and vapor retarder, while unfaced boards are more breathable. : Home Depot and Menards are primary sources