If they move or come off do not tile over them.
How to install new tiles over old tiles on walls.
Roughen the tile with 80 grit sandpaper.
Mix degreasing cleaner with water in a bucket using a dilution recommended.
Epoxy tile adhesive bonds with existing tiles making it one of the best options for tiling over an existing tiled wall.
Try and lever the old tiles off.
Go around the walls with a sharp scraper and dig it into the grouted joints.
If the old tiles are in bad shape the new tiles won t adhere correctly.
Prepare the surface for installation.
Thoroughly vacuum the area and give the wall a once over with a damp sponge or cleaning cloth.
If they do simply make the spaces smaller or eliminate them altogether.
If your old ceramic tile is worn or dated you can lay new tile right over the old and avoid the huge job of tearing out the old tile.
Grind them down with a grinder.
Sand with a medium grit sandpaper to create a uniform surface that s not too smooth.
Strip them all off and start again it simply is not worth the risk.
Position your tiles according to the layout you choose.
No matter whether you are tiling over tiles on a floor or a wall your new tiles will need a stable base.
First clean and then sand the surface of the old tile until it feels rough.
Tiling over an uneven surface will give you less than stellar results so level out any globs of dried grout with a sander and secure loose tiles with fresh.
If you plan to do this backsplash project over existing tile you will have to make some modifications.
Second apply a very thin coat of thin set mortar filling in the current grout lines.
Using a modified mortar with latex or polymer additives creates a stronger bond between the existing tile floor and your new tiles.
This provides a more even foundation for the new tiles to adhere to.
And third let this coat dry for 24 hours.
You want the tile adhesive to have something to grab onto.
The basic tiling process is the same as any tile installation.
Working in small sections spread the thinset over the existing tile using a notched trowel.
Use liquid nails and pay attention to the spacing to see if your tile and grout lines show through.
Lay a level on the old tile and mark any high spots.