New shower - sealing advice required

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Hi

As part of our new extension I am installing a shower in a shower room (Inc WC and basin). The walls around the shower cubicle are waterresistant plasterboard and the floor is 18mm waterresistant chipboard.

I plan on having wall tiles floor to ceiling throughout the shower room and floor tiles accross the whole floor.

First, should I tile the whole floor including under the shower tray? (I have plenty of tiles)

The shower tray is a grp/plastic type with a welded steel support structure under the tray. (Came as combined tray/cubicle system) It is of the raised type with adjustable legs. There is no built in riser for sealing.

Should I provide any sort of reinforcement to the floor under the tray? (200x50mm floor joists at 400mm center's)

Should I tile right down to the floor or fit the tray tight against the wall and tile down to it? and how would you recommend I seal it to the tiles?

Any other advice?
 
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Paul_Thomas said:
First, should I tile the whole floor including under the shower tray? (I have plenty of tiles)
No.

The shower tray is a grp/plastic type with a welded steel support structure under the tray. (Came as combined tray/cubicle system)
Does it come with a removable panel to provide access to the trap?

Should I provide any sort of reinforcement to the floor under the tray? (200x50mm floor joists at 400mm center's)
No need to. But you should screw the flooring to the joists, because nails can work loose.

Should I tile right down to the floor or fit the tray tight against the wall and tile down to it?
The latter. Leave a 2mm gap between the bottom tile and the tray surface

how would you recommend I seal it to the tiles?
Dow Corning 785. Don't be tempted to buy cheap sealant.

Any other advice?
Follow the tray and enclosure manufacturer's instructions to the letter.
Ask them, or here, if you're unsure about anything.
Sort out the waste before fixing the tray in place.
If it has feet that are supposed to be screwed down, then screw them down.
Before tiling, seal the side of the tray (at the top edge) to the wall using silicone sealant.
Use top quality waterproof tile adhesive.
Use top quality waterproof tile grout.
 
Thanks for the comprehensive reply,comments below:-

Paul_Thomas said:
First, should I tile the whole floor including under the shower tray? (I have plenty of tiles)
No.

The shower tray is a grp/plastic type with a welded steel support structure under the tray. (Came as combined tray/cubicle system)
Does it come with a removable panel to provide access to the trap?
No, 1 piece unit.

Should I provide any sort of reinforcement to the floor under the tray? (200x50mm floor joists at 400mm center's)
No need to. But you should screw the flooring to the joists, because nails can work loose.
Already done, I haven't used any nails for the floor and all boards are glued along the tongue/groove in every room.

Should I tile right down to the floor or fit the tray tight against the wall and tile down to it?
The latter. Leave a 2mm gap between the bottom tile and the tray surface

how would you recommend I seal it to the tiles?
Dow Corning 785. Don't be tempted to buy cheap sealant.

Any other advice?
Follow the tray and enclosure manufacturer's instructions to the letter.
Ask them, or here, if you're unsure about anything.
Sort out the waste before fixing the tray in place.
Waste pipe is already in floor ready, it has a compresion fitting ready to accept the flexible pipe coming from the shower trap - Trape is factory fitted.

If it has feet that are supposed to be screwed down, then screw them down.
Before tiling, seal the side of the tray (at the top edge) to the wall using silicone sealant.
Use top quality waterproof tile adhesive.
Use top quality waterproof tile grout.


You don't advise any of the flexible rubber strips that go behind the tiles/shower tray then?
 
i would never fit a pastic tray. EVER. they are cheaper for a reason. they move .they will flex ( in time ) and if you are on the large side, even crack. i only ever install resin trays (stone ) with the up stand for tiles to drop into the tray. and also only with feet with access to the trap .even though you sould only install a trap with top cleaning access. also good sealer. like i said you only get what you pay for and the extra cost for this now will be nothing to repair it in the future.
 
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Paul_Thomas said:
You don't advise any of the flexible rubber strips that go behind the tiles/shower tray then?
Sorry - I don't know what you're referring to, but they sound like carp.
 
Paul_Thomas said:
You don't advise any of the flexible rubber strips that go behind the tiles/shower tray then?
Sorry - I don't know what you're referring to, but they sound like carp.

I read about them on some of the posts on here, it would appear they stick onto the top of the shower tray and fix behind the tiles, creating a watertight seal.

I have made a big effort to ensure the partitiion walls where the shower is are exactly at 90 degrees so your original installation suggestion sounds the best idea. (Unlike my existing bathroom where the in-bath shower has just had to be resealed again because the walls are more like 85 degrees resulting in a large gap.I have filled with expanding foam and sealed with silicone. As long as it lasts 12 months I'll be happy as I plan on rebuilding this bathroom with the wall 18" further back (and square!)
 
i would never fit a pastic tray. EVER. they are cheaper for a reason. they move .they will flex ( in time ) and if you are on the large side, even crack. i only ever install resin trays (stone ) with the up stand for tiles to drop into the tray. and also only with feet with access to the trap .even though you sould only install a trap with top cleaning access. also good sealer. like i said you only get what you pay for and the extra cost for this now will be nothing to repair it in the future.

I appreciate the comments, however this is an anusual shape cubicle that came with it's own tray so changing it isn't really an option.
 
You don't mention any wall treatment prior to tiling ?

If all you have a facing is plaster board - albeit moisture resistant, then don't worry about water running down the wall into the tray - it will simply permeate into the wall and seep down to floor and onwards.

Tank the walls (Bal or Dunlop products I can recommend), the tanking will allow a flexible seal to be established between the tray and the walls.


As for plastic tray, if you're stuck with it, then try to add additional bracing by means of a raised frame under the tray - something like noughts and crosses type frame should work - coupled with the supplied feet and fixing to floor, it should be the best you can do with the material supplied.
 
You don't mention any wall treatment prior to tiling ?

If all you have a facing is plaster board - albeit moisture resistant, then don't worry about water running down the wall into the tray - it will simply permeate into the wall and seep down to floor and onwards.

Tank the walls (Bal or Dunlop products I can recommend), the tanking will allow a flexible seal to be established between the tray and the walls.


As for plastic tray, if you're stuck with it, then try to add additional bracing by means of a raised frame under the tray - something like noughts and crosses type frame should work - coupled with the supplied feet and fixing to floor, it should be the best you can do with the material supplied.

Thanks for the advice, I will look at wall treatments.

The plastix tray has a metal welded frame inside it that the legs are joined to. I presume this is the kind of thing you were on about making for it?
 
I assume the tray to have the frame around the perimeter - tucked under the side flange.
The trouble is the plastic bases tend to allow so much flex, that additional bracing is required if you're to minimise the likelihood of movement.

If the legs that come with it elevate it say 4 inches,. then use addiitonal 4 x2 on edge, screwed into a box type frame. I'm not explaining this well, but if you draw a tic tac grid using two parallel lines, intersecting and additional two parallel lines at right angles, then you have a pln view of what I'm poroposing.

This may need adjusting of course depending upon waste and pipewrok, but you get the idea of how it provides much welcome additional support to the weioght bearing plastic tray section.


If you do decide to tank walls - which I truly recommend for time and cost it will incurr up front rather than repairs prematurely down the line, Trades Direct are a great source with competitive prices and fast delivery.
 

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