Ditra is a polyethylene uncoupling underlayment with a grid structure of square cutback cavities and an anchoring fleece laminated to the underside. Ditra provides uncoupling through the open rib structure which allows for in-plane movement that effectively neutralizes the differential movement stresses between the substrate and the tile, thus eliminating the major cause of cracking and delaminating of the tiled surface. Ditra provides waterproofing and vapor management. Underlayment for tile.