Leaking shower waste

29 Sep 2011
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United Kingdom
Hi There

Bought a house last year and put a new bathroom in, Dad fitted everything and it's all been great.

However, we lost him last year just before he was going to finish a few bits in the bathroom, one was some sealant around the shower waste which needed re-doing to tidy it up

So I took it apart :oops: and re-did the sealant, and a week later it's started leaking through the ceiling downstairs

This isn't a slow drip drip, this is about 60 seconds after finishing the shower, water comes out downstairs at quite a pace. Probably fills a couple of cups dripping for an hour or so then stops until next shower

I think I'm putting it back together how it was, there's not much to get wrong really

There is the waste under the tray which has the "female" type of thread, it has a rubber ring around the top of it, under the tray, then on the top of the tray there is the drop-in top connector which is threaded and has another rubber ring to go between it and the top of the shower tray

Dad has sealed this part

My hunch is that the part under the tray is not pulling up high enough/tight enough to make a good seal, and as the plughole fills with water, it travels up and over the waste

I'm trying PTFE tape on the thread, and I think I'm getting it right. The whole thing seems to screw quite tight and then pop, it jumps up a thread or two and come loose, so it's a bit of a frig to get it to where you think it's tight enough

But as I say, this isn't a tiny leak, this is water coming out at quite a rate as you see it come through the plasterboard ceiling downstairs soon after

It doesn't happen with the sink next to the shower, so I don't think it's a general leak on the waste system

Plumber due tomorrow, but surely I can figure this out?????

this is a similar fitting;

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There needs to be a handsome squidge of silicone between the top part of the fitting and the shower tray......if the threads are jumping and the waste isn't fully compressing together, then I'd really go for a new quality waste.
John :)
Thanks for that John

Would the rubber seal not do enough of a job to just cause a drip drip leak at worse though?

What I'm getting at is, whilst I will re-seal that part once I'm happy with it, does the fact that the water is leaking fast mean it's probably not that at fault?

Would it be worth trying to put mastic along the rubber seal that's under the shower?

I'm thinking just get a plumber out, get him to take the show and tray out and fix it for me
Not trying to be patronising here at all, but these waste fittings are designed to fit all applications rather than your specific one.
Only my opinion here but often any gasket material between the water outlet and shower tray (topside) can get squashed or squeezed, or even let the outlet stand proud of the tray - its something that only can be decided upon on site.
So - a good squidge of silicone it is, so that it squeezes out between the waste and the tray. That is held down whilst you connect the piece underside. Theoretically the ribbed rubber washer is fine (as it shouldn't leak now anyway) but another silicone smear does no harm.
Once you are happy with that, then the two pieces of the waste are fixed together - which should make the first layer of silicone ooze out even more.
If you want to see quality products, McAlpine stuff is first class.
John :)
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Not patronised at all! I don't even register as a novice....

I'm not sure what you're saying about connecting the underside after using sealant around the top

At the moment, the tray is down, sealed, screen on top, floor tiled etc, so all I have when I unscrew the top piece is the waste fitting below, loose, with a rubber gasket between it and the underside of the tray

Then I screw the top piece in with another gasket between that and the tray, and until I took it back out today, that did have a bead of sealant all the way around, and I don't think that part is leaking

I think the problem is that the thread is knackered as when I get to a point of tightness, it just pops and comes loose. It shouldn't be doing that, right?

So I think my only course of action here is to get someone in to take the tray and screen out, put a new waste in, and put it all back together

I just wondered if I was missing something and there was a way of fixing this without taking the tray out

I just think the top piece cannot pull the bottom piece tight enough to form a good enough seal

One more thing, looking at the waste under the tray, the "female" part of the thread doesn't go all the way around. It's sort of split into 3 parts going around the circumference of the waste. Does that make sense?

What I'm thinking is, water doesn't even have to try and work it's way up past the thread there, it can just flow straight up to the gasket and if that seal is not right, it will just flow out under the tray

Bit gutted to have to have it all taken out, but hoping it will all go back and the only new parts will be the new waste
Ok me again, sorry for rambling away here, but I might as well have a bash at this as it will take a couple of days to get a plumber and I can't make it any worse. honest :eek: :eek:

I just saw that the silver insert on the top, if you remove the "hair trap", will act as a "key" to tighten the bit below

It seems as though I can get it quite tight with that, perhaps because it's forcing the fitting to stay in place and not jump off the thread?

I'm thinking; bead of mastic around the opening on the underside of the tray (to sort of increase the thickness of the gasket under the shower tray), then thick bead around the opening on the top of the tray, screw it all tight with the silver cover piece, leave it 24 hours then run the shower flat out for 10 minutes and see if I get a leak

If I do I'll admit defeat and get a pro in

Worth a go do you think?
I think you are on the right track....whatever happens, you don't want to have the tray removed if at all possible - there are tiling issues involved with that one.
As suggested - go for it!
John :)
Cheers guys

Spoke also to a builder friend of mine late last night and he said we'll cut the ceiling away in the kitchen to get to it and put a new waste in, as that's so much easier than taking the tray out and perhaps disturbing the tiling

I'll give this fix a go to see if that works and then he said he'll be about at the weekend to replace it if it doesn't

This is almost identical to a problem I had (noticing a pattern here?? :unsure: ) when fitting my new kitchen sink. The waste pipe would only screw on to the sink waste so tight before popping down off the thread. When I got it to it's tightest point before it jumped, which seemed quite tight to me, it leaked water quite bad, so I think that gave me an insight into how much water can get out of a connection that might seem reasonably good but isn't as tight as it could be

I bought a new waste pipe but had exactly the same issue but managed to fix it by using a bead of Fernox LSX around the gasket, which sort of increased it's thickness, and then getting the collar as tight as possible. That doesn't leak at all now, so I'm thinking something similar would work here

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