Refitting my shower tray (base advice)

[welshwibble]

Hello peeps
I am currently up to my neck in an en-suite re-fit, quite enjoying the challenge, my question relates to the refitting of the shower tray. The tray is 1000mm X 800mm composite , i was going to mount it on some 4"X 2" with some ply on top to support it . However a well-meaning mate (self appointed DIY expert) tells me i need to mount the ply or waterproof chip on top of the 4 X 2 and then cement the shower tray to the base, i was simply going to silicone the tray to the base
Any comments / advice
My thanks in advance

 

[seco services]

what does the mi say ?
follow them if you want to keep your warranty.
and don't put it on chipboard. 18mm marine ply etc.

 

[welshwibble]

To be honest the instructions that come with the tray are pony. (bath store .com) it only really concerns fitting the tray to a solid floor i dont have that luxury need to raise it for access etc . I thinkcement seems a little over the top but dont want any movement which could affect the seal

 

[Dan Robinson]

It might seem over the top - but do you want to have to take the thing out and rebuild later.

With shower trays - belt 'n' braces dear boy!