hi my name is Don and i am trying to find out if i use modified thin set instead of unmodified thin set between the plywood subfloor and the backer board will i encounter any serious problems down the road
Hardie tells you to use either modified or unmod to install the board, and modified only to install the tiles. You are not necessarily trying to bond the board to the subfloor. The thinset under is there to support the board so there is no movement. Problems down the road? Removing it in 20-30 years.
TILE GUY - retired- TROY, MI - Method & Product suitability consulting.