Re: Does hi-density styrofoam hold up well to the sun and other elements? Should I pa
Here's what Dow Chemical, the owner of the Styrofoam brand says:
STYROFOAM™ Extruded Polystyrene Foam Insulation must be covered to protect it from sunlight (UV or ultraviolet light). It should be covered within 90 days of its installation. Sunlight will very slowly begin to degrade the insulation, changing the surface from a rigid blue plastic to a yellow powder. This does not change the properties of the insulation below the surface, but it can result in a loss of insulation thickness over very long periods of time (years).
USDA Zone 7A Elevation 1400 ft