Schluter Systems demonstrated Schluter-Ditra, underlayment for tile and stone, at Surfaces 2002 in Las Vegas. Ditra is a pressure-stable polyethylene membrane with a grid structure of square, cutback cavities and a laminated fleece underside. Ditra was designed to enhance the uncoupling, waterproofing and vapor pressure equalization of the matting. The product weighs 2 ounces per square foot.