green HDPE board 1/8 inch price-Cus-to-size HDPE sheets, lored HDPE Use 1/8" thickness over existing bacit such as plywood or OSB. 1/4" thickness and above can fastened directly to stud walls. Dimensions: 1/4" x 4' x 8'. lored HDPE Sheets - 2 lor HDPE Sheets okay Plastics.