760 stone resin shower tray flooring help

[Adam c1]

Hi im currently ripping out ensuite and fitting a 760 square stone resin tray. Existing floor is chipboard and spongy at that,due to an old leak from the previous owner. I have already read about reboarding with 18mm plyboard but i thought i saw somewhere about sitting the tray directly on the joists (waste pipes permitting) it i create a suitable frame around it.
Can anyone advise on this??
Many thanks

Read more: //www.diynot.com/diy/threads/760mm-resin-shower-tray.469402/#ixzz4O75RU5cb

 

[ajstoneservices]

If you read the tray manufacturers instructions it will probably say the tray should be fully supported.

 

[Nige F]

Directly on the joist would have been a stone tray ( like a belfast sink) not stone/resin.

 

[Adam c1]

Thanks for your thoughts, so i will replace chipboard with ply and sit on the ply floor Whats your thoughts on setting the tray down?? Silcone/pinkgrip/ mortar bed?
Thanks

 

[Cgas]

Again as Aj pointed out instructions are your friend here to get the warranty if ever required. Usually mortar mix though for most.