You want water to readily absorb into it.
Can you install tile over painted concrete floor.
Before you lay any sort of tile whether it is stone ceramic or peel and stick vinyl you must prepare your concrete floor to ensure that the tiles will go down properly and stay where they re.
You need to prepare by removing the paint and scarifying the surface to open up the pores of the concrete.
No big deal hack or grind the epoxy coated surface to form keys and tile over.
As long as the paint is down well and not flaking you can go over it with some preparation.
Ceramic tiles will not adhere to an enamel painted floor because the surface is too smooth.
Paint used on concrete will not bond with the tile adhesive.
Painted concrete can be made porous with sandblasting or other hard abrasive actions.
But there is a solution to the problem.
Sheets of cement backing available from most do it yourself.
All paint will need to be removed before you begin installing the tile.
Unfortunately the tile cannot be adhered directly to the painted surface.
The thinset will probably bond to the epoxy floor.
If you use a stripper to remove the paint be sure to flush it thoroughly to remove any residuals.
Tile cannot be attached directly to painted concrete as the thin set will not adhere well to the paint.
Once the concrete floor is paint free the tiling process is similar to most other floor tiling jobs.
While you can install tile directly on concrete problems erupt when the concrete cracks or shifts.
Sand or scuff it up well and wash to get.
The tile installer is right.
As long as there are not structural cracks in the concrete floor you can install porcelain tile over it.