cracked tiles

[DHTiling]

From what i remember they built it out of ply.

There's your answer...Expansion stress cracks..more than likely at the board joints.

 

[simhopper]

Or they used wet ply that is drying out and shrinking

If the crack was caused by water ingress then it would buckle rather than split

 

[HEM]

Thanks guys! Any tips on what to look for when we remove the damaged tiles?

Is there anything i can do to minimise chance of repeat (which doesn't involve retiling the entire wall)?

 

[White Room]

Theres no easy answer for this, as diamond has said, the wall is getting moisture into it and it could be better to replace with the hardie backer.

 

[Sean Page]

Hi Hem

No easy way, what ever you do to resolve the problem is always likely to show as a patch. Probably best to remove and retile the whole wall. Could maybe try one of the mat systems which would act as a decoupling membrane too and absorb some of the movement