PURLINS WITH 68 YZ WCCO SCREWS. FASTEN EVERY THIRD CORRUGATION iff MEACH PURLS& END LAPS TO BE ED OVER A PURUN. SIM LAPS TO RCVELMEWAINggent S' O.C. Al.!. SCREWS TO HAVE AMIN. 1/2' WA HEAD &A NEOPRENE WASHER. ATTACH PURUNS THRU PLYWOOD DECKING (OR EOUALITORAFIERS WITH 2-68 X 3172' WOOD SCREWS. CO