Tiling under shower base

[Scott]

Shower trays are normally bedded on sand cement either straight to floor or ply on timber upstand.

Some of the newer low profile trays can be fixed with Silicon as they are acrylic capped resin (not stone resin tho). The website doesnt state the material of this tray so you will be limited to manufacturers installation instructions. However depending on their details it could make a difference if it will stick to the tiles

 

[Gazebo]

Have you got the wickes aquapanel 12mm wall board (heavy grey cement board)
Or have you got the wickes aquapanel floor INSULATION board which is 9mm or 10mm and made from a cement foam sandwich.???

If you have got the later then it is primarily used for concrete floors where ufh heating systems are to be fitted.

It will not add any structural integrity to the chipboard floor. neither will the wall board.

you might want to change the board to hardibacker or no more ply. (aslong as the floor has no deflection that is.

Cheers and good luck.

Gary