I've painted over tiles twice--once in a kitchen backsplash, and once in a bathroom. I still own the house with the painted bathroom tiles, and they look the same as they did 5yrs ago when I first painted.

The kitchen was done more than 20 yrs ago, when one purchased the paint in two parts, mixed them, and raced against the clock. The second time I had nothing to mix, and the work window was much longer. In both cases, I was told that if you have the paint tinted at the store (as opposed to buying pre-tinted standard colors), it has to be a light color--too much tinting medium will affect the paint.

I didn't scuff sand, but cleaned with a '409' type spray, and rinsed well. Also, although it wasn't recommended, I used a fiber roller rather than a foam roller. I wanted a slight texture, which is very subtle, as the epoxy paint was self-leveling. If you use a regular roller, I'd suggest that you first use sticky tape to remove as many loose fibers as possible, to avoid leaving them in the paint. I have a few, but they're not noticeable unless I'm looking for them--no one else would see them.

I applied two coats, following recommended drying times. I should add that both times I covered light colored tiles/light grout with a cream color--dark tiles might need extra coats.

Bathroom:

I will echo what mama goose said- go for it! I also did it several times with no problems. I used Kilz primer that covered every type of surface and a semi gloss with a foam paint roller. Prep is important as is the right paint. Good luck!

Can I ask if the tiles look "painted" and if any of them are in a shower area? We built almost 10 years ago and will be selling in about three years. I do NOT know what I was thinking, but I agreed to dark green tiles, I think 10x10 or close, in a large master bath. Up the shower walls, on the front of the corner tub, and on the floor. The room gets plenty of light so it not a big deal to me but I am almost sure it will be a turn-off to potential buyers.

I was glad to see this question come up!