Extruded polystyrene is a dense, closed-cell rigid foam insulation manufactured through an extrusion process. It provides a consistent thermal resistance and is highly resistant to water absorption, making it the standard choice for below-grade foundation insulation and under concrete slabs. Builders easily identify it on site because manufacturers dye the boards distinct colors, most commonly pink or blue.
Heard on the job
We need two inches of XPS against the foundation wall before we backfill the trench.
Also heard as
- blue board
- pink board