An extremely perplexing choice for you to make whenever re-tiling is whether or not to lay tiles over current tiles or perhaps get rid of the outdated ones to start with. It shouldn't become an issue if you decide to lay over the current ones on the wall, however there are still some factors to make note of whilst thinking about laying over ones already in place.
This way of doing things is actually a poor job in all honesty, however, if you have to do it this way, basically you need to be sure they are free of moisture prior to starting. They do not require any form of roughing up or even scoring so to speak. You should definitely establish battens in order that they will not slide in addition to staying level. In order to tile directly over old, current ones you should, work with an appropriate cleaning agent or perhaps some form of suitable cleaning solution that will eliminate most of the debris and grease and so forth to them, achieve this through horizontally as well as vertically marking your tiles employing a purpose scrubber, this can help to attach the old to the new.
If you're contemplating tiling directly onto others that have been on the wall for many years, you'll need to bear in mind that this makes the newly laid tiles proud of the wall. Because you have tiled on top of the old ones and not removed them, this can cause problems when you consider such things as door frames and skirting boards.
The vast majority of instances when doing such a job as this is, it's significantly better to clear out the current tiles. This might mean your task will take longer as well as be a lot more time intensive but ones final tiling outcome will undoubtedly be clearly deserving of the actual additional effort and time.
One more reason you want to stay away from tiling on top of ones already in place, besides time and expense, is the fact that for those who have a superior quality restroom there's a danger of damaging the wall surfaces whilst taking and knocking the old ones off the wall. This can be a possible issue although it is possible to avoid any damage if you take your time and prepare properly.
Preparing well is the solution to the above method. But in all honesty it is far better to make yourself enough time to strip the wall back to it's bare surface and start from there. It may seem like more work but very often the end results are far batter