I have a washed concrete floor i wish to tile over. What do i need to do? Do I need to make it smooth first? What do i put down over the concrete or can i just put the mastic down or use backer board? Thanks Bill
Read on. And where is this floor? Below grade, exterior? You would not use mastic ever on a floor. You do not need cement board on cement? Even sounds silly! What do you mean by smooth? It needs to be flat and level. Remove all bumps with a grinder and fill in dips with thinset allowing it to dry. What is washed? Yes it must be cleaned. After proper prep I would use Ditra as an isolation membrane to prevent the movement in the concrete to transmit into the tiles cracking them. If this floor is below grade Ditra will also provide the necessary water vapor barrier.
By washed i mean concrete that has had enough cement removed to expose the gravel. this floor is in a breezeway that we have just enclosed. It also was painted over some time back. If i intend to tile over it what are the necessary steps?