Installing shower tray on suspended floor

[Phil0185]

Tray is stone cast resin low profile, 1200 by 900. Suspended floor is receiving all new 18mm P5 chipboard floorboards.

There is plenty of talk of replacing floorboards under the tray with marine ply. Is this advice assuming the bathroom still has old style floorboards and that new P5 chipboard will be fine? One article suggested cutting out the floorboards and fitting ply flush with the top of the joists (sinking the tray down slightly) whilst other articles put the ply on top of the joists. The tray is low profile and the floor tiling will bring the floor level up the side of the tray so I’m not keen on sinking the tray down onto the joists.

And what about fixing the tray down - mortar or adhesive?

 

[ShaunCorbs]

Depends on what look you want eg if you want the tray near enough flush with the tiles / flooring you will have to sink it / infill the joists

And I would always do ply under as if it gets wet it won’t break down like chipboard

 

[Phil0185]

Depends on what look you want eg if you want the tray near enough flush with the tiles / flooring you will have to sink it / infill the joists

And I would always do ply under as if it gets wet it won’t break down like chipboard

OK, I reckon that'll be too low so I'm gonna go with sitting it on top of the floor.

What's your opinion on mortar versus adhesive?

 

[ShaunCorbs]

Depends on the tray and if there’s big voids on the bottom of the tray if flat tile addy I use