XPS can be attacked by many petroleum-based solvents in adhe­sives, paints, stains, water-repellent or preservative coatings, and bituminous waterproofing. Solvents should be allowed to evaporate before touching the foam.

XPS must be protected from sunlight because, over time, ultra­violet (UV) light degrades it. When installed on the job and left exposed to the sun, the surface of XPS becomes yellow and dusty. (The dust can be brushed off before installation.)