Extruded polystyrene insulation, or XPS, is a closed-cell, rigid insulation that allows for fewer air gaps and issues than the more commonly used expanded polystyrene insulation.
The closed-cell structure of XPS makes it strong, durable and long-lasting. It has a compression strength superior to expanded polystyrene insulation and is one of the few products that can provide both insulation and moisture management at once. With just one product to install, XPS helps you get your job done more easily while providing benefits that your clients will see for years.
You’ll find XPS in rigid foam board which is easy to install over the exterior of a home, including over existing siding. XPS boards come in several thicknesses, with some measuring as thin as a quarter inch. This allows you to insulate without adding a lot of bulk to the exterior.
Being able to use a thin board is a huge benefit when you need to install insulation over existing siding. It doesn’t dramatically increase the thickness of the walls and has a smooth and level surface, ideal for installing new siding over old siding.
XPS is also considered water-resistive and can promote moisture management in the home’s building envelope. Use it alone or with an interior vapor barrier for extra protection. For optimal performance in regions with fluctuating temperatures, you can also perforate the surface for better moisture management.