At Johnston Industrial Plastics, we provide our customers with the high density polyethylene (HDPE) plastic sheets, rods, rolls and fil in Canada. High Density Polyethylene Sheet. High Density Polyethylene Sheet Natural. properties and applications. Size: 48″ x 96″, 48″ x 120″, 60″ x 120″. Thickness: 1/16″- 3″.