Tiling in Bathroom

[The Question Asker]

Hi, I am tiling a friends bathroom from top to bottom. She has chosen very large tiles with sharp edges NOt like razor sharp but right angled) Seeing the installed in the showroom they have left no gap for grouting and they look quite good placed tight with one another. I have just a few questions relating to this:

1) Can we tile over the old tiles, things such as plugs, el;ectric showers will be taken off and placed on top of new tiles, what surface prep is required as the tiles have been previously painted.

2) What would be the best way to tile, when taking off tiles in the past I have noticed just four or five blobs of adhesive on the back, but I feel this wont be strong enough should the whole wall be covered?

3) Is it ok to place tiles tight with one another should a very thin layer of grout or maybe clear silicon be placed in between??

Cheers Oli

[Laurie R]

A grout line gives you some manouvre for non-flat surfaces - the eye won't spot a difference between (say) a 3mm grout line in some places and 4mm in others. But no gap in some places and a 1mm gap in others will stand out. Also you're likely to get capilliary action between nominally flush tiles, but the gap will be too small to seal (conventionally, anyway)

[chris French]

In message , The Question Asker writes

Yes, you can tile over the old tiles as long as they are sound. If they have been painted I would probably sand first.

Yes, the 5 blob method is not good practice,

Details may vary from adhesive to adhesive, but general recommendation seems to be to spread a bed of adhesive over the wall with a notched trowel and then lay the tiles on that. For very wet areas a continuos bed can be used.

IMO for one it would look awful anyway with the tiles dead tight (as the other poster pointed out any unevenness would be more obvious' and to my mind one of the things that makes tiling look good is the grouting lines :-) If the gap is to small then the grout won't have enough space to go into and adhere properly.

You can use a small gap though, 1-2mm

There is useful stuff in John Schmitt's Tiles and Tling FAQ

[The Question Asker]