broken floor tiles being tiled onto

[spenny]

hi guys,
i have a floor to do that has existing tiles on, however the reason the customer wants to get new tiles is because a few of the tiles have cracked, however remain in place so as to not look too obvious(think they have been cracked for a number of years now)
To tile straight onto these, do you think i should lift the few cracked parts of tile and stick some fresh ady under them? What is best thing for me to do?

[GazTech]

Better to knock em up spenny. Then infill with cement or some old tiles b4 tiling over them

[Branty]

I wouldn't tile onto them without investigating why the tiles have cracked.
If you have movement in the substrate, then there's a good chance the new tiles will crack.
What is the substrate?

[davy_G]

Im with Branty, find out why the tiles cracked, remidy, then continue!

If they dont want to pay you on time to check it out first.....walk

[spenny]

yeah, just as i thought-basically make sure why the tiles cracked in the first place,then ensure they wouldnt crack again, but carry on as normal and tile on top of the existing tiles-i think best bet is to clean under the broken tiles.

Why are we ok to tile onto floors on top of existing tiles, while not encouraged to do so on walls-is it soley because the wall may not support the weight,while obviously the floor will?

[medlar]

I wouldn't tile onto them without investigating why the tiles have cracked.
If you have movement in the substrate, then there's a good chance the new tiles will crack.
What is the substrate?

Bang on mate,my sentiments exactly