This material is not suitable to use as house cladding; even after painting the panels, moisture can still penetrate through the paint when the ply Treatment: Treated Plywood is an F14 structural rated ACQ (Alkaline Copper Quaternary) treated ply, similar to CCA but free of arsenic. It offers protection against insect attack, fungi, termites and wood-boring insects. The H3 level indicates that this product is suitable for outdoor, above-ground use. This plywood is all veneer treated, not envelope-treated. Veneer treatment is the superior method as it allows the panel to be cut yet retains its preservative properties. Envelope-treated plywood, when cut, must have the preservative re-applied to the cut edge.