Laying Porcelain Tile Over a Painted Cement Slab

[mrsbobvila]

I plan on laying 2200 square feet of porcelain tile over a painted or stained cement slab. The house was built in 1989 and I believe that is the age of the concrete. The paint or stain is in excellent shape with no flaking. Using rock board seems to be a lousy option as the area has a potential for flooding and the product doesn't look like it mixes well with flooding disasters well. What I need to know is this: is it absolutely necessary to remove the paint? If so, what is the worst case scenario if I choose to skip the step?? If I must remove the paint, what is the easiest way to do it (i.e., what machine should I rent) and how ugly and time consuming would the job be? Thanks a million.

Barb

[mrsbobvila]

In my continuing pursuit of an answer, I went directly to the company who makes thin set. They advised me that their product cannot bond to painted surfaces of any kind, so I am stuck with removal of the paint or affixing a metal lathe material to the slab similar to how stucco is applied.

Barb

[floorman]

I don't know why you would have to attach the metal lathe to the concrete?All you would need to do is to remover the paint and then isolate the cracks and then tile it.
This metal lathe does not need to be put on the floor,make sure the slab is clean and free of any oil,grease, dust, paint etc.If there ARE ANY SAW JOINTS OR CRACKS IN THE SLAB YOU WOULD NEED A MEMBRANE to isolate those cracks either an elastomereic one or paint on but you do not need the lathe.
What type of thinset were you going to use anyway?Not that it matters ,just wondering who would tell you that[8D]

Floorman
floorlayers union local 1310