Is my shower tray in need of repair?

[nwrmartin]

Hi,

I’d be grateful for some advice about my shower tray. I was showering a couple of days ago when there was a quite a loud sort of cracking noise, and I felt something shift under my feet, though nothing really changed. The shower tray now creaks slightly when I shift my weight on it.

I’ve looked under the tray and found that it rests on some thick plyboard on top of a wooden frame, which lifts it off the ground and makes room for the drain (photos attached). Everything seems absolutely fine under the shower as far as I can see (though the drain makes it difficult to see a large part of the bottom of the shower, including where the creaking happens). I can’t see any movement when people stand on the shower.

My guess is that the shower tray sits on a thin bed of mortar, and for some reason the mortar has cracked during my shower. I don’t know why (I’m not especially heavy, though it is occasionally used by a person who is quite heavy).

If that’s what’s happened, can I just live with the creaking, or am I in trouble and need a repair; maybe to rebed (or even replace) the tray? I know these are fairly big jobs.

Could something else have happened?

Any advice as to next steps? I’m looking for ways to diagnose or even repair, if I even need a repair. I should say I’m not sure how far I can take this as DIY, but I’m willing to give things a go.

Thanks for your help.

 

[oldbutnotdead]

Plastic or resin tray? Any movement under the tray is going to be bad news. Your first step is determining whether the movement is between tray and ply or ply/timber and floor joists. You need a friend, a good torch and maybe one of those budget endoscopes for your phone- get the friend to step in and out of the shower while you watch to see what is moving relative to what.
Any repair under there will be a bit of a mare, if the ceiling of the room below is featureless (no coving or stuff like that) it'll be much cheaper and easier to cut a trap out of the ceiling and do it from belowm

 

[nwrmartin]

Thanks, I thought you might say that. I have done the movement test you suggest (I don't have the endoscope though - that sounds like a good bit of kit!), and can't see any movement at all, either between the ply and the joists or the tray and the ply. If it wasn't for the slight creak, you wouldn't be able to tell something was wrong. Not sure where that leaves me.

If I was to get a professional in, should I need to speak to a plumber or a bathroom fitter?

 

[nwrmartin]

Plastic or resin tray?

I am not sure, and am not sure how to tell them apart. I’d guess at resin.

 

[oldbutnotdead]

If there's no sign of a crack in the tray, no movement between tray and tiles above, no sign of leaks from the waste pipe then you might be as well to carry on using the thing and monitor the situation. Anyone you call in will see the same as you have seen, only way to see more will be to get under the thing.
My personal suspicion is EDIT same as yours, that whatever bedding was used to the plywood wasn't well done and is no longer supporting part of the tray. A plastic tray will flex a bit at such a fail, a resin tray won't.

 

[nwrmartin]

Thanks, that’s helpful. I was thinking I might have to do that. I’ll keep an eye on things and update the thread if I find a solution (or learn more about the problem).