Oldroyd Xv20 is a large (20mm) stud-size cavity drainage membrane with applications in waterproofing, drainage, and ground-gas control Oldroyd Xv20 benefits from large 20mm dimension studs providing greater drainage and flow capacity than standard cavity drain membranes. For this reason Oldroyd Xv20 is ideally suited to civil-engineering applications and the waterproofing of large commercial basements.