Polyethylene foam plank extruded in thickness of greater that 1/2 inches, for use in the further manufacture of packaging, physical therapy aids, sporting goods, toys, boats, dock bumpers, floatation booms, floating pool furniture, personal floatation devices, surf and body board construction, boat cushions, buoys, spas, hot tubs, wall padding, aerobic steps, exercise and camping mats, golf bag and backpack inserts, archery and dart targets, car top boat carriers and racks; and for use in construction and engineering applications, namely, floor underlayment, concrete curing blankets, pipe insulation, sill plate gaskets, separation and pressure relief joints in foundations, roofs, floors, and concrete pavement; closure strips and gaskets, buried cable protection, underground oil and gas pipeline protection, tunnel linings, acoustical insulation, vibration isolation for heavy equipment, and pool liners and covers