how to stop floor tiles cracking at edges ?

[Gary111]

Hi, several floor tiles have cracked at the edge where it meets the carpet.

Ive chipped them off to replace them and found the tiled area has been plyboarded.

theres a bit of movement when you stand on the edge im guessing thats why they cracked.

Im planning on ising flexible tike adhesive , will that be enough to stoo them cracking or should i do something else too ?

 

[Bonni]

Cut up the area, make solid, re plywood it and use flexible adhesive.