How can I replace marble with subway tile on a fireplace surround?

If the marble is in good shape you can tile right over it.

You will have to chisel off the existing tile. Then you can put the subway tile in place if the cement board is in good shape. If not, then you may have to replace that as well.

Etch the marble so that the tile has something to grip. Then you can tile over it. You could also try painting with epoxy paint and a stencil to make it look like subway tile.

If you want to tile over a marble fireplace, you have to address the problem of tile adhesion. Wash the marble with a solution of 1 cup trisodium phosphate (TSP) per gallon of water. Wear gloves and a mask because this is a caustic detergent that won't only remove soot, grease and etch the marble, but it will also give you skin burns.

Get out your pad sander and a fairly coarse grit of sandpaper, such as 60- or 80-grit. Since you're about to tile over the marble fireplace, you don't care about the condition of the marble, so go ahead and scratch it up as thoroughly as you can.

Use the right adhesive – An epoxy-based tile mastic. Do not use a cement based thinset.

Hi Janet, If you want to tile over a marble fireplace, you have to address the problem of tile adhesion. One strategy is to clean the marble with TSP and water, then sand it with coarse sandpaper to etch it. Then, if you use the proper mastic, the tiles should stick. You can also install cement backer board.

https://www.hunker.com/13402384/how-to-tile-over-a-marble-fireplace

Don't do it. Marble is beautiful and subway tile is a fad and doesn't look that good and everyone has got it! Trust an old lady - keep the marble!

How about using thin Luan wood cut to fit with removable caulking holding in place and THEN put the subway tile on it. That way it can be removed without damaging that fantastic and expensive marble when you go to sell. It looks as though there is enough space on the edge of the moldings to allow this to work. Personally can't figure out the subway tile . . . I urge you to somehow not damage the marble if you have any plans to sell your home in the future. I personally pray subway tile disappears as it just screams cheap fix after watching it all over TV. And for a few dollars more you could have much nicer tile maybe if you feel you must change this. This is not a huge project so low dollars in cost.