14 in. (6 mm), 12 in. (12.7 mm), 58 in. (16 mm) cover plywood base with usg durock™ brand tile membrane, 15 lb. (6.8 kg) felt or 4mil polyethylene and attach with 14 in. (6 mm) galvanized staple. position. fit ends and edges of panels closely but not forced together. stagger panel joints from plywood base joints.