Natural Stone Installations over Wood Sub-Floors
Did you know that natural stone installations over wood sub-floors require a mandatory second layer of subfloor before a backer-board or DITRA can be installed? The detail from the Schluter Systems DITRA installation handbook (D-W-S and DPS-W-S page 6) shows this requirement for this application. We emphasize this detail as often as opportunity allows, specifically during our Innovation Workshops. We make all handbook details and information readily available in both printed and digital formats. Schluter has adopted this second layer requirement from TCNA (Tile Council of North America), F141-25 and F250-25 details. The two accepted assemblies are either (1) a wire reinforced mortar bed over a slip sheet membrane (minimum 1 1/4” & max 2” reinforced mud bed), or (2) a second layer of OSB minimum 3/8” thick before (a) approved tile backer-board or (b) Schluter DITRA Uncoupling Membrane (as noted in our detail). It does not matter how firm you feel the floor is. It does not...