Bedding Shower Tray

18 Aug 2005
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United Kingdom
I've been doing a search on bedding a shower tray, and have come up with the following suggestions if I want the tray to sit as low down as possible on the floor (assuming I have enough of a gradient left for the trap/waste run).

- Replace floorboards with 18mm WBP Ply, leaving hole for trap/waste
- Bed down onto a mortar mix and level flat
- Wait till dry - Tile and Seal afterward

It's also been mentioned to build up the tray onto a wooden frame before bedding down. Is this necessary, and what does it entail exactly? I want the tray to be as secure as possible - does the mortar mix 'stick' to the WBP Ply effectively to stop the tray moving?

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I would make a frame with 6x2 secured to the wall / floor, screw a sheet of marine ply on top and then Gripfill the base to it and the sides to the wall.

Leave access to the trap and buy a matching fascia to cover the frame. :D

I'm hoping to replace the current floorboards with 18mm WBP Ply - Is it ok to build the frame at the same level as the current joists, and then ply on top of that to make it level with the rest of the floor?

Am I right in assuming that whatever I use to bed it down (gripfill/tiling cement/etc) will stick to the ply as well as the shower tray?
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Gripfill will stick like **** to a blanket. :LOL:

I've only done a couple of shower trays so I am not an expert but my cautious nature is such that I would always want access to the trap in case of leaks and blockages.

Maybe the others can help you further. :D
Gripfil sounds like a good idea - has anyone tried using the 'wooden floor' tile adhesive for shower trays?
A 5:1 sand cement mix will do fine on the floor just seal between the wall and the tray with a good silicon then you can tile down onto the top of the tray then seal the tile to the tray where it meets.
If for any reason you ever have to take the tray out if you grip fill it will be a smash out or lift the board/s it's on.
Sand/Cement mix will probably be cheaper as well. I was just a bit concerned that the tray might move after a while if the bedding compound doesn't stick to the WBP Ply correctly, and the whole piece (tray + bedding compound) comes loose. From the sounds of it, mostly anything I use shouldn't have that problem.

Cheers Guys!
Well we used to bed them on silicone but the stupid manufacturers have started prrohibiting that. I tried sand and cement it didn't work for me. AFAIK mortar never sticks to wood. I use plumba grip similar to gripfill.

It's true that you have to smash it out. We don't build them for later removal just like the guys before us didn't.

Access under showers is essential, unless it's on the ground floor or there is access from underneath instead or you are incredibly optomistic. I come across optomistic people all my workaday week who were proved wrong.
To provide access i'm going to get a 'top access' soil trap in-line with a HepVo valve. I'm going to connect into the soil stack further down, outside the bathroom, so i can have access to it for rodding purposes, and so I can fully tile the bathroom. This leaves the trap/HepVo joints for possible leaks, which I won't be able to access without taking the floor up...
That's the problem, leaks under showers. Keeps us in work. Wise man he say raise level and make side panel that removes.
You can buy trays which come on legs, with side panels. They save hours. 800 sq was about £100 so not prohibitive. Tested with 3 plumbers, combined weight 50 stone +. Passed. Yes it was cosy. Wears the soap?

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