Schluter-Ditra understands that tile, being a hard, brittle substance, expands and contracts due to moisture and temperature related conditions, at a totally, different rate from whichever substrate material lies beneath, be it plywood, concrete, cement, etc. This can be a problem when using traditional, thin-set mortar bed applications, which bond the tile directly to the supporting structure. The result is usually cracked, ruined tiles. In order to ensure both layers can move independently, an additional layer in between the two materials, is a must-have. (And no, you can’t just lay any, random thing down. Just in case someone out there is thinking, “Huh. I don’t see any reason I couldn’t use this old comforter.”) The Schluter-Ditra Universal Underlayment is the better option.
Schluter-Ditra is an uncoupling membrane system designed specifically for tile and stone installations. The membrane provides a shear interface within the tile assembly, which allows the substrate (base) and surface (tile or stone) to expand and contract independently of each other. It’s made of a thin, polyethylene sheet composed of a grid of square cavities with a fleece anchored to its underside for stability. Installation is easy:
- Apply a layer of thin-set mortar over the floor surface and embed the Schluter-Ditra, fleece side down, using a float or screed trowel
- Fill any joints with thin-set mortar and cover with the Schluter-KERDI-BAND, centered over the joints to ensure
- Fill the cavities with unmodified, thin-set mortar and lay your tiles
(For some reason, I equate this process to building a sandwich; ergo the only thing on my mind right now is a loaded, Italian sub.)
The system is lightweight and easy to handle, supports heavy loads, is waterproof and acts as a vapor barrier. This is so important considering tile and stone are highly susceptible to water penetration.
Schluter-Ditra is available on Amazon for $489.99 plus shipping, (323 sq. feet.)