Fitting a ceramic (stone resin) shower tray

[David WE Roberts]

I am slowly working my way through fitting a stone resin shower tray to replace a collapsed foam tray. It will have to be a raised installation to match the height of the previous tray as I don't want to retile etc.

The instructions which come with the shower tray tell you to that for a raised installation it has to go on at least 18mm ply and then must be bedded on a layer of cement to give an even bed.

Now the shower trap I have has a minimum distance of 15mm and a maximum distance of no more than 25mm between the base of the shower tray and the horizontal waste pipe run. This seems normal for most of the traps in the sheds.

Given that my installation will be 18mm of ply plus an estimated 10mm of a cement bed this means that the horizontal waste will not fit. Even with a 5mm bed of cement this leaves only about 2mm clearance and I would also have to cut out an extra space for the plastic compression connection where the trap joins the run of waste.

Some questions:

(1) Is it acceptable to cut a 50mm wide slot from the waste to the edge of the ply or would this weaken the whole thing too much?

(2) How deep a bed of cement would you normally expect to use when bedding in a shower tray ? (Enough to allow you to level it up, obviously.) [I am expecting to go a bit thicker to compensate for a slight undersize in the platform from using standard thicknesses of wood.]

(3) If not (1) then what do I do? Just use a normal bath waste? I wanted to use a shower waste trap because that can be fixed from above after the tray has been fitted instead of having to fix it from underneath before fitting the tray, which makes the it easier to keep the holes to a minimum instead of having to leave enough space to pass the trap through.

Cheers

Dave R

[Lobster]

Not entirely sure I understand what your problem is, but I certainly did the above when I fitted mine (using a standard shower trap), and it was fine.

I think I used about 0.75". See here for one useful thread on the practicalities of how to do it painlessly!

(or

[David WE Roberts]

My problem really is reading the friendly manual - it shows (in the diagrams) boring a circular hole for the waste and says to remove as little wood as possible. I can also see that the unsupported edges near the waste pipe are not nearly as rigid as the rest. However I am probably over thinking this. I did in the end cut out a slot in the ply and all looks fine at the moment.

Using my imperial to metric converter (also known as a tape measure) that comes out at about 20mm. I only want to make up about 10mm so that should be fine.

suggestions including removing the roof ;-) Strangely, nobody suggested using a small fork lift. Fortunately this tray is not as big so I can lower it by hand. Also, there is a channel all the way round where the rim is, so the main mortar bed will be in the central part of the tray where you stand. This makes installation easier because you are not relying on the far edge.

Hmmm...just had another idea for fitting big shower trays. Cut a round hole in the middle of the ply, place a small hydraulic car jack under, balance the tray on this (positioning it with a sling if required) and let the bottle jack down. If it is small and the platform is high you can then recover the jack. Or leave it in place in case you have to remove the tray later :-)

- thanks for the helpful advice. Much appreciated.

[Rick Hughes]

bedded mine on semidry about 10mm deep. p[roably about 6mm by the time I settled it in.

Lowering in 1200mm x 900 trays took some effort