Advice - Tiling on top of floor tiles

[stan1888]

Hi new to the forum, some very interesting reading on here !

Looking for some advice, might be tiling a 20 sqm kitchen floor which already has ceramic tiles. Will use a flexible cement based adhesive with flexible grout. I think the tiles may be porcelain.

Is there any other considerations i need to take into account?

Any advice would be welcome, thanks !

[whitebeam]

Are the ceramic highly glazed, do they not want the existing tiles removed before you lay

[Dave]

Is there any other considerations i need to take into account?

Yes!!...Stress factors....

[stan1888]

It was originally a concrete floor and they would rather the tiling was done on top of the tiles. There is actually two different set of tiles down (additional tiling was done when the kitchen was extended). One set is unglazed, the other highly glazed.

The tiles that are down are solid and there seems to be no faults, however there is no expansion gaps in the original tiling.

Should an additive be added to the adhesive to increase flexibility etc? Dave what advice would you give to counter any stress factors, any suggestions would be more than welcome, thanks !!

[timeless john]

Movement joints are for sub base structures and if not in view you can not provide them - apart from around the perimeter of the room. They are usually recommended in tiling over 4 meters long but not just for the sake of putting them in.
I suppose a cup of tea would take away the stress factor!
Don't forget to check the additional height of the tiling for under worktop appliances - they have to come out sometime.
Mapei make a primer for the surface of tiles and then overscreed with Mapei fibreplan
John.

[stan1888]

A cup a tea it is then !

Thanks for the advice