If the tiled area is 95 free from hollow sounds it is good for tiling over.
Tiling over existing tiles in shower.
Then rinse the wall with a water dampened.
And it lasts for 20 years.
While tiling on tile is a great solution for outdated tiles it s no solution for an existing tile job with issues.
The best way to check the tiles for drumminess is to tap each one with the back of a screwdriver and listen for a hollow sound.
Tile on tile or as i say it.
Moisture and steam from your shower can easily creep behind these tiles.
Don t worry if you do pull a bit of plaster when stripping the tiles as it s easy enough to replace.
It could even lead to mould growth.
If your old tiles are loose drummy lifting too uneven or badly damaged they are better off removed.
When this occurs moisture will continue to build up threatening the plaster and dry lining which lies behind the tile.
Complete adhesive coverage is critical on large tiles 12 in.
Tiling over tiles can make it awkward i e.
When you are tiling over tiles however you will always have one section of edges that shows.
Damaged tiles or tiles that are literally lifting off your floors or walls provide the perfect entry for water.
At diy doctor we use double glazing plastic trim to hide these edges.
For the sake of a few hours work i would take them off.
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.
Normal tile trim is ideal for hiding the cut or unsightly edges of tiles.
Extra thickness when tiling around shower fittings.
Or larger and even more important when you re tiling over tile.
Mix degreasing cleaner with water in a bucket using a dilution recommended by the cleaner manufacturer.
Some installers prefer to flatback each tile with the flat edge of the trowel before applying the tile to the combed thin set.
When there is a double thickness of tile it is much harder to disguise.
Others prefer to use a larger notched trowel 1 2 x 1 2 in to apply the thin set.
Before you begin tiling over tile conduct a thorough assessment of the base layer to pinpoint any surface irregularities which can cause foundational problems down the road.