scope:

General

Virtually any Exterior type APA panel can be used for concrete formwork because all such panels are manufactured with moisture resistant adhesive. For concrete forming the plywood industry produces a special product called Plyform®, which is recommended for most general forming uses. The term is proprietary and may be applied only to specific products which bear the trademark of APA - The Engineered Wood Association. All Plyform panels have Exterior bond classification, made with C or better veneer and moisture resistant adhesive.

Overlaid panels, including "Medium Density Overlay" (MDO) and "High Density Overlay" (HDO) may be manufactured for concrete form use and, if so, are designated "Concrete Form" on their trademark. During plywood production, these overlays are bonded to the plywood under high heat and pressure in a press. The function of the overlay is to add stability, repel foreign substances from the surface and provide a smoother and more durable forming surface. The thermosetting phenolic resins used in overlay production are hard and resist moisture, chemicals and abrasion. HDO is most often specified where the smoothest possible concrete finish and maximum number of reuses is desired.