Very easy diy that will save you hundreds of dollars not paying a contractor.
Tile over tile in bathroom wall.
Roughen the tile with 80 grit sandpaper.
Grind them down with a grinder.
Mix degreasing cleaner with water in a bucket using a dilution recommended by the cleaner manufacturer.
You can tile over tiles with the right preparation but i would never do this the proper way is to strip right back to original wall finish.
Always stagger your joints when putting new tiles onto old tiles what to do at the edges where double thickness of tiles show.
Scrub the wall tiles with diluted degreasing cleaner and a nylon scrub brush.
Layer newspaper on the floor across the bottom of the tiled wall.
Tile on tile or as i say it.
Bjd building roofing say.
Then rinse the wall with a water dampened.
Generally speaking thin set adhesive also known as thin set mortar is great for setting tiles in areas subject to moisture like bathrooms while mastic adhesive is best for drier spaces like.
Original tiles on wall the existing tile joints are in yellow.
Lay a level on the old tile and mark any high spots.
Learn the largest tile industry secret to remodel your bathroom for just 200 bucks and 1 days work.
And it lasts for 20 years.