On 02/06/2019 21:41, ss wrote:
I havent ordered tray yet.
Ideally I want a 1200 x 800 tray.
Unfortunately the waste connection would be directly above a joist.
A longer 1300 tray all appear to have the waste in the middle of the
tray and would need to attempt access to connect from the adjoining room
so trying to avoid that. I am trying to achieve a sort of walk-in so a
shorter tray I am trying to avoid.

Any thoughts on how to solve this I am reasonable at DIY, plumber will
make connections though.
See image.

https://imgur.com/fOlOTuR

When I put in our shower, there was a joist partly in the way. I used a
shallow waste, with an elbow mounted straight onto it, dropping down the
side of the joist and notched the joist (and the floorboard above from
underneath to clear the elbow). The notch in the joist was only a few mm
more than already used elsewhere by 3/4" pipes installed from new and
the joist was no longer having to support a full bath, so a little loss
of strength did not concern me.

SteveW