Plasterboard oN or behind resin shower tray?

[Maisymoo]

Hi all,

I am getting conflicting messages from my builder and plumber regarding fixing a new resin shower tray in a new bathroom. The builder wants to recess the tray so the plasterboard butts on top of the tray, but the plumber wants to fit the tray flush against the board and then have the tiles on top of the edge of the tray. Which is the best practice to ensure a good seal ? I also have some bal bond sbr to seal the plasterboard prior to tiling - is this the right stuff to use ?
many thanks for any advice.
maisymoo

 

[Gazzer]

Hi Maisymoo and welcome to tilersforums.com 🙂

 

[Dougs Third Go]

Hi maisymoo, personally I prefer the tray to fit flush to the plasterboard, as long as the walls are square. No need to prime the boards, however tanking them is advisable.

 

[tommyzooom]

The PB on top of the tray will be a nightmare to seal, also you will be "losing" part of your tray in the wall, and will find it hard to find doors to fit your tray .
For example, your 900 tray will now be 888mm, and it still has to be tiled.
Better to plasterboard down to the ground and tank the inside of the shower

 

[Colour Republic]

hmmmm there is no right or wrong way but butting the tray up to the plasterboard is the preferred option rather than sitting the plasterboard on top.

It never use to be a problem as old style trays had wider profiles and tiles were often thin cheap ceramics. But now modern shower trays have slim profiles and edges, in addition people sepnd more on their bathrooms so often opt for more expensive or natural stone tiling which is thicker. So if you plasterboard on top of the tray you run the risk of losing the edge or worse your shower door won't fit as the gap is too small.

You shower door will have specs that state the opening needed. Often something like 860mm-900mm. So say you started with 900mm, now take away the thickness of 2 polasterboards either side (25mm), you're now left with 875mm, so that leaves 15mm for tiles either side, not forgetting adhesive.... you can see where the problem lies.

Board it first
Lay the tray,
Tank the walls (recommended)
seal,
tile,
seal again.

 

[Andy Allen]

depends if the tray has a 20mm lip on it these trays are ment to be resesed in the wall, if not then as above fit flush and tank walls.

 

[DHTiling]

Some trays l etc have an upstand lip .. these need the plasterboard to be cut to allow the tray to recess back , so that the tiles fit in front of this lip...

tray in pic :

then you have flush fitting trays and these usually just fit flush back to the wall with no recessing of the plasterboard... :

It is advisable practice to waterproof the background substrate but not law as yet in the uk.

IMO i would follow the advice of your plumber if a flush fitting tray.