shower tray: tile under ok? cement or tile adhesive ?

[stusuffolk]

Hi guys - last minute question from a newby so hope you don't mind:

my plumber/fitter is fitting a low profile resin shower base tomorrow and also tiling the whole room as part of a refurb.

it's tiles and tray onto a standard green grade chipboard floor (good condition)

First question: most places seem to be suggesting cement/sand mix required under base. Is this really required or would the topps tiles flexible tile adhesive they are using for the rest of the floor and tiles not be fine ? I found a few places saying this, but most saying cement required ?

Second question: they are suggesting tile floor first then fit base on top. It's very low profile 30mm, so I'm not bothered from that point of view, but everything I can find on the internet says base should be fitted to chipboard direct then tiled around.

I can see that this saves them cutting curves in tiles (its a quadrant) and might be a cleaner finish, but they'll be silicon around base anyway surely.

this is the base if it helps - with it being SO low profile it does seem that cement would be a bit of a waste of time ?

https://www.drench.co.uk/drench-anthracite-slate-effect-quadrant-shower-tray-800mm-900mm

 

[bobasd]

Mfr's will tell you more.
cant realy advise you to many unown factors an ive never installed such a thin base.
whoever does the job must be experienced in fixing an plumbing in such a base.

is the floor solid or suspended?
wll you have future access to the trap an waste?
presumably youl have an enclosure - its not a wet room?