National Gypsum® is a fully integrated manufacturer and supplier of building products used worldwide. Primary emphasis is on Gold Bond® BRAND gypsum board; ProForm® BRAND drywall finishing products; PermaBase® BRAND cement board products; eXP® fiberglass-faced interior and exterior gypsum board; an XP® family of abuse, impact, mold and moisture resistant products; and DEXcell® BRAND roof board products.