I have had my kitchen floor tiled using 60 x 60 ceramic tiles, we sheeted with ply and used all the correct adhesives, but crack line appeared which run in line with the joints in the ply underneath.
We have lifted and want to do these again but are worried incase it happens again - any advice would be greatly appreciated.

You say you sheeted with ply but what thickness? did you stagger the joints? leave expansion gaps ? , Screw down correctly ? Prime back and edges of boards ?

hi there,how thick was the ply and were the sheets staggered or one continuous line where the boards meet?

where the crack happened was it grout that cracked? as in did you land a tile edge running continually up a line where the ply sheets met? ie a weak spot so to speak

assuming the correct ply was used and there is no deflection in the floor then a uncoupling membrane would be the solution to the problem IMO.

What is under the ply..?