Order this Standard Sheathing Plywood for delivery to your job site. 4-ply plywood construction. Can be nailed directly to framing – wall studs and roof or floor joists. Recommended for projects where knots, splits and knot holes are acceptable or for use under drywall, roofing materials and flooring. Not recommended for exposed applications or applications where beauty is required. NAUF (no added urea formaldehyde) water-resistant phenolic resin. Manufactured to construction and workmanship requirements for grade, veneer and panel thickness, as outlined in the (APA) – The Engineered Wood Association’s Product Standard 1-09. Product is not sanded. Storage in a warehouse or under roof is recommended prior to use. If stored outdoors, units should be off the ground and covered loosely with some type of protective material.