Floor grout problems

[ChrisR]

1) Suspended bathroom floor, ply cover, 5mm gaps, Ivory, a few years old. Tiles about 300 sq. . Cracks have appeared along the edges of some of the tiles, and some short lengths of grout come loose.
Is there a super-flexible grout which could be used? If we scrape out a fair bit of the exisitng and regrout, would that do?

2) Concrete floor 3months old tiling. "Microban" grey grout is variable in shade, going from parts where it looks wet through to whitish grey areas.
We're sure it's dry. What might have caused this? What should we do?
Uneven mixing?

 

[petethetiler]

you should have used a flexible adhesive to lay the tiles on, if you did it means theres still lots of movement underneath still, so without ripping it all up you can buy a movement mastic that comes in various grout colours, weber make it or n&c , and with your grout discolouring it could ither be old grout u used, not mixed rite or adodgy bag, you ither rake it out n do it again or just make a little bit up wetter than usual and just go over it that way, try , ,

 

[ChrisR]

The tiles on the wood floor have been there years, at least they aren't coming up!
Is the
"movement mastic " hardish like grout or softish like silicone?
Does it go on like grout?

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For the new, shaded stuff, how deep do you think a layer of new grout floated over the top would need to be?


Ta.