John wrote:
Haymish Pupkin wrote:
Hi All

I need to seal a shower tray but the tray is 0.5"-1" away from the wall at
the back (the wall facing you as you walk into the cubicle). I have filled
the hole with plumbers mate putty and now I'm not sure what to do next.

I could fit a long thin strip of WBP ply over the gap along the length of
the back wall so that it over hangs across the tray by half an inch or so,
then I could seal / stick it to the walls / the shower tray with no more
nails or silicone or something where the ply meets the tray, then tile over
the ply and seal with grout. Does that make sense? I assume nothing will
stick to the putty I have used. Would someone walk me through the process of
what I should do / not do to seal a gap like this?

I had a similar problem with a shower tray that didn't fit a shower
cubicle. In my case the gap was about 3" all round. To add to the
problem, the floor joists underneath were old and flexed. (The house
was nearly 300 years old and replacing them wasn't a realistic option).
The previous owners had built a wooden frame around the shower try and
tiled onto that. The tiles had cracked as everything flexed. That let
water onto the wood which eventually rotted making matters worse.
I ended up filling the gap with expanding foam, cutting the top to a
slight fall and tiled on top of that. In order to maintain flexibility,
I grouted the tiles with silicone. I used 4" tiles cut to overlap the
shower tray by about 1/2". If the tiles didn't seal, the foam provided
a secondary seal. After 6 years, the structure was still perfect.

John


Top marks for a practical solution to an otherwise almost insoluble
(haha) problem.