Schluter®-DITRA-DRAIN is a drainage membrane designed for use within thin-bed ceramic and stone tile assemblies in exterior applications. DITRA-DRAIN is typically installed over the Schluter®-KERDI bonded waterproofing membrane. If the substrate does not require a waterproofing assembly (e.g., drained mortar bed), DITRA-DRAIN may be adhered directly to the substrate.
DITRA-DRAIN consists of a studded polyethylene sheet with a laminated polypropylene filter fabric. Some of these studs are approximately 3/32" (2 mm) high inverted truncated pyramids, which form square undercut chambers on the underside. These studs facilitate the mechanical anchoring of the DITRA-DRAIN to the substrate with thin-set mortar. The remaining studs are approximately 5/32" (4 mm) high truncated cones, to which the filter fabric is laminated. These studs support the tile covering and effectively distribute loads to the substrate. Tile is installed over DITRA-DRAIN using the thin-bed method in such a way that the mortar is mechanically anchored in the filter fabric.
Drainage and ventilation
The free space between the filter fabric and polyethylene sheet provides ventilation for the tile bond coat to enable faster drying after water exposure compared to other thin-bed tile assemblies. The continuous free space also ensures water that drains through the ventilation layer cannot seep back into the tile covering (capillary passive drainage).
DITRA-DRAIN provides uncoupling through its geometric configuration, which allows for in-plane movement that effectively neutralizes the differential movement stresses between the substrate and the tile.
The closely spaced cones are able to sustain high compressive stresses and provide effective support for the tile covering.