DIY related: Tile-to-tray sealing options

[plato]

For a JT40 type low-profile shower tray....
(1)..in absence of a tiling upstand on the tray rim what is the preferred/recommended method to best guarantee a watertight seal on tray sides adjoining wall? Any options more secure than a straight silicone seal?

(2) ... the walls will be lined with nomoreply backer board. Am I best advised to present this tray directly against fully encased nomoreply walls ..... or to create an undercut effect by terminating the nomoreply close to the upper rim of the tray to create an increased 'overhang' (when tiling added) on to the rim for water run-off?

Thanks.

[silver]

Hi Plato,
When I did one of these gave me the same headache...it went against my limited experience and logic to "tile into" the tray due to poor finish to the tile edge....marking out would not guarantee a full tile starting in the tray. Plus thinking there would be some degree of flex in the tray especially if a larger person got in.
so I put all my thoughts into creating a situation that would not let water past the lip and would allow me to tile flush into the tray past the lip.
The only way in my mind too was to recess the tray to create a flush level or use a larger adhesive comb.....To be honest I may have done this wrong ? .... I will put my hard hat on here guys !! be gentle with me !!!
In my moment of "What would I do if it was my home"
I chose to recess the tray.
I ensured the tray could not move side ways or to or from. But it was now flush with the wall.
I then filled the small tray to wall gap with silicon, then I tanked the shower area bringing the web into the tray onto masking tape.
This allowed me to tile onto the web (Wall / tray edge) and cut off as normal then re silicon neatly. I knew the tray could not creep and pop off a tile sitting to the tray edge....it worked for me....and is still.....no complaints
Though If I am truthful I dont like the finish of a tile edge in a tray as opposed to it sitting neatly on / past a rim.
When I did this I was new...and ....I was not aware of the forum...the forum would be my first route given the time again....you have done right to ask.......
...Ok guys let me have it !!! LOL