Travertine crack accross 4 tiles

[Rich]

As above. If there is bounce in the floor, chipboard or ply, you need more screws and more noggins.

 

[DavieA]

Here's an update on the upcoming floor. Spoken to joiner and he has no way of adding noggins between joists because of the ufh pipework so advised not to use sheets of ply as under every joint must be supported. Which makes sense, so if chipboard is used which is obviously 22mm thick and t&g, screwed to joists can (if the floors solid and bounce free) cement board such as hardi be fixed as per Richs post using a thin bed of addy and screwed at 150mm centers into the chipboard?Thanks all for any input on this.