Bedding in stone resin shower tray

[Fallout]

If bedding a stone resin shower tray down on floor boards can I go straight on to the boards if secure? Or is over bording with ply needed? Also is a weak mix and sand and cement OK to bed down on too? Or would flexible floor tile adeshive be better? Thanks.

 

[denso13]

Straight on to the boards with tile adhesive for me. There are different opinions though...

 

[Madrab]

I'd be lifting the boards and putting cross joist supports in (dwangs) and then refit the boards so minimising long term movement. I'd then put a WBP plywood topper down and then tank the space.

Personally I never take any chances with showers and water. Lifted too many rotten floor nightmares, simply due to being fitted straight onto floorboards that subsequently haven't stayed watertight due to movement, which then bursts the seals.

In fact I'm stripping one out on Wednesday for that exact reason, that and they used softwood plywood that's just turned to mush. I'll take photos when I'm taking it out.

 

[gasbanni]

Some thin marine ply if the floors good then tile cement ..............you want the tray to undercut the plaster, preferably
Remove the plaster from waist height down and fit hardibacker boards in the showering area.

The tiles want to finish stood on the horizontal lip of the tray.......do not but up the tray to the tiles !!!!!

 

[BoilerBob]

I’d tank to be safe. Bob

 

[bobasd]

gasbanni,
fwiw: whats the purpose for using of a piece of (expensive) marine ply below the tray?
if fitting backer boards then its a case of doing all walls with backer board to approx a six foot height - or to total wall height if its more convenient in terms of keeping wet walls and dry walls in plane.

there's also always the nagging business with shower trays of access to the waste and drain?

 

[JP_]

Use that sealant tape around the shower - my plumber used. .. will find out what it's called ....

https://www.bellabathrooms.co.uk/classi-seal-shower-tray-and-bath-sealant.html

I have this stuck to my tray, with hardbacker right behind, and the tiles will go over this. I assume the bathroom fitter / tiler will stick this down to the hardiebacker too, so if water gets behind the tiles then more chance it will not end up on the floor.

 

[gasbanni]

gasbanni,
fwiw: whats the purpose for using of a piece of (expensive) marine ply below the tray?
if fitting backer boards then its a case of doing all walls with backer board to approx a six foot height - or to total wall height if its more convenient in terms of keeping wet walls and dry walls in plane.

there's also always the nagging business with shower trays of access to the waste and drain?

I just like it in case of a bit of water getting on to it ........It's not expensive for my customers as I just use an offcut from a timber mill
I've got two near me. I know the tile adhesive won't affect it or swell it when applied before it cures.

 

[gasbanni]

It all depends on what the job is ....a lot of times I use breeze blocks on their sides. Leaving access to the trap.......

If you don't know when you use the legs wrap the threads with ptfe !!!!! It stops the leg threads squeeking when the shower tray is in use. But I prefer breeze as it just feels so so very solid !

 

[bobasd]

very few have timber mills local.

but the ply is only doing the same as any flooring - only with the extra layer.
adhesive or S&C on the ply will have no more significant advantage than adhesive or mortar on the floor boards.

 

[bobasd]

jonbey,
the stuff you propose wont do - sticking the seal on the apron of the tray will allow any moisture that runs down the backerboard to keep going down behind your sealing tape.
thats unless you start siliconing, which kind of defeats the object.


there are other bath & shower tray similar seals that stick to the rim of the fixture and are folded up to stick to the backer board or p/b.

thing is with all these self-sticking tapes is that they can fail within a year or two depending on exposure to hot water and expansion & contraction of the fixture. failure means hidden mould slime.

my suggestion is always use trays &, if possible, bath tubs with fins.
from behind the backer board vapour barriers or similar can be brought down over the fins, & held in position by the bottom course of tiles.