Can you paint over XPS to protect it from sun?

RamblinRose | Posted in General Questions on September 19, 2011 07:33am

I put on a house addition with XPS on the exterior. I won’t be able to side it until next year, leaving the foam exposed to sun and elements.

Is it advisable to coat it with a latex paint or housewrap?

Answer

GBA Prime

Join the leading community of building science experts

GBA Editor

Martin Holladay | Sep 20, 2011 05:35am | #1
David,
Here is some information on leaving Dow Styrofoam exposed to sunlight: "It should not be stored outside under sunshine for a prolonged period of time (over a month) to avoid excessive exposure to sunlight (UV). A sheet of polyethylene film may be used on top of the STYROFOAM Brand XPS Foam Insulation to prevent excessive exposure to sunlight (UV)."

The information is found on this website: http://dow-styrofoam.custhelp.com/app/answers/detail/a_id/3373/~/how-should-i-store-styrofoam%E2%84%A2-extruded-polystyrene-foam-insulation%3F

If you do choose to install polyethylene on top of the XPS to reduce UV exposure, be sure to remove and discard the poly when the siding is installed.
kevin_in_denver | Sep 20, 2011 08:49am | #2
Latex paint works well to protect it from sun exposure. I've done it. I wouldn't try to push it much past one year, though. It does nothing to prevent damage from rodents and birds, which could be a consideration.