Can I leave Fox Blocks forms exposed to ultraviolet rays for an extended period (months)?

Yes, but you will notice a light dusting on the surface and a yellowing discoloration of the forms. This does not indicate any detrimental effects to the ICFs. We do suggest, that if the exterior finish is not going to be installed within around a 3 month period or more, the forms be protected from UV rays by installing a temporary building wrap type material. The powdery film must be removed with soap and water before the application of a synthetic stucco finish or waterproofing membrane.