Designed specifically for ceramic tile and dimension stone installations, Schluter-DITRA serves as an uncoupling layer, waterproofing membrane, and vapor management layer that accommodates moisture from beneath the tile covering, the company says.  DITRA performs all these functions while still providing adequate support/load distribution for the tile covering.  DITRA is a polyethylene membrane with a grid structure of square cavities, each cut back in a dovetail configuration, and an anchoring fleece laminated to its underside.