Advanced Drain® is an effective and eco-friendly drainage composite tough enough to handle any roof top soil load. Its durable drainage core flexes under foot and lightweight traffic, leaving an open structure for maximum, multi-directional water flow. The heavy-duty polyester filter fabric lets water pass through, but keeps soil particles from clogging the core. Advanced Drain® promotes unobstructed water and air flow to help keep the structural elements of the roof in peak condition. Advanced Drain® is available in .40 (10mm) or .50 (13mm) thicknesses.