How do Warmboard panels hold up during construction?
Warmboard panels are rated Exposure 1, as specified by the APA – The Engineered Wood Association. The APA trademark is the consumer’s assurance that products, which bear its stamp, have met specific manufacturing and product performance standards. As an APA approved product, Warmboard panels can handle exposure to rain, snow, and ice. In fact, the aluminum top surface of Warmboard acts as a ‘built in’ weather barrier making it even more impervious to rain and snow than standard Exposure 1 plywood. During construction Warmboard panels can be walked on, bracing can be nailed off and sill plates can be nailed directly to them. In general, Warmboard Radiant Subfloor should be treated in the same manner as any other plywood subfloor. It should be noted that it is normal for plywood to experience minor amounts of bowing, due to humidity swings (especially during shipment). However, the panels will lay flat when they are fastened down over the joists and secured with construction adhesive and
