The Natural Philosopher wrote:
Lobster wrote:

(this scenario is exactly
why I favour using more expensive waterproof board like Aquapanel,
rather than plasterboard as has been used here by the looks of things.


Disagree. As long as the board is firmly fixed, and properly sealed it
never gets wet anyway.

I agree with your disagreement(!) but have seen enough leaking showers
in my time to know that leaks are likely to happen, and if they do, then
the extra initial cost of providing a decent substrate is piffling in
comparison to the extra work which the OP's now faced with.

Actually this is a case where expanding foam would work. It will seal
the gap and it is rigid enough t tile over.

Hmm, possibly but not convinced. Even if if the foam's rigid enough, I
don't fancy the OP's chances of achieving a surface which is flat and
firm enough to tile over. Could he fill the deep gap with foam and then
bring it up to the right level with something else non expanding, maybe?
All very awkward to do with the height of the gap being so small.

Maybe worth a go though, and use my over-tiling suggestion afterwards if
it still leaks?!

David

David