Installing expensive tiles on a poorly prepared wall surface will result in a much less satisfactory finish compared to fitting cheaper tiles fitted to a well prepared wall. It could also lead to disaster and costly repair work.
Proper preparation ensures that your tiling job will stand the test of time.
If your bathroom is currently tiled, assessing the exact course of action to take (regarding wall preparation) can only really be done once the old tiles are removed from the wall – see Ukbathroomguru for details.
If you currently have plastered and painted or wallpapered walls that you wish to tile you will need to follow the advice below prior to tiling:
Tiling on painted walls
Tiling on painted walls is dependent on good adhesion between the paint and the surface to which it has been applied, and not just the adhesion between the tile and the paint.
It’s no good ensuring the tiles are well stuck to the paint, if the paint peels off the plaster behind!
Remove any old wall coverings and flaking paint with a wallpaper scraper. Fill in any large cracks with a suitable filler, and ensure the surface to be tiled is smooth, clean and free from dust, dirt or grease.
Tiling on wallpaper – DON’T DO IT!
Ensure all wallpaper or wall coverings are stripped prior to tiling using a steamer and wallpaper scraper, and the surface to be tiled is smooth, clean and free from dust, dirt or grease.
If you do not, the moisture in the adhesive will soak into the wallpaper and cause it (and the tiles) to fall off the wall.
If you have rendered & plastered walls try to avoid using a wallpaper steamer to remove the old wallpaper. Steaming off wallpaper on these types of walls is likely to cause the old render to fall away from the wall behind.A better option is to use a sprayer to soak the wallpaper (in warm water or a wallpaper removing product) a couple of times before scraping it off with a wallpaper scraper. PS Adding washing up liquid to the mix increases the viscosity of the solution and stops the solution running off the walls immediately.http://www.dummies.com/how-to/content/getting-to-know-wallpaper-removal-techniques.html
If you currently have tiled or partly tiled walls, you should remove them before re-tiling in which case you should go to my article Preparing walls for tiling – removing tiles.
If you are tempted to tile over the existing tiles (this approach is never recommended) please read my article Tiling over tiles.
Follow the links above for the next step to preparing your walls for tiling.