Diagnosing and fixing a leak in a first floor bathroom

[Feltwell]

Great to hear you're making good progress Nigel, also glad to hear that the multi-tool worked out well - always a little trepidation in recommending tools for jobs for others to spend their hard-earned cash on!

I too swear by LSX, great stuff - but like any sealant over-enthusiastic use can cause problems in some situations. I have to say though that my preference for waste pipes is always to use solvent weld pipe & fittings, not only are they neater than push or compression fit they're also pretty much guaranteed to never come apart or leak. However, you need to have the right type of plastic pipe to use it, so in your current situation I'd stick with compression fit.

In your picture, is the straight connector badly mis-aligned with the pipes either side or is it just the camera angle?

Glad to see someone making progress! My kids went back to school last Tuesday, "I'll be able to get on with some work & projects" thinks I. My youngest had other ideas - he fell off his scooter (non-powered type - he's only 4), but he really did it properly, resulting in a trip to A&E, an operation, 24 hours in hospital, 5 less teeth than before and lots of stitches - ouch! He's on the mend now but won't be winning any beauty prizes for a bit. You can tell he's feeling better today - he's started arguing with his siblings and being cheeky to me, normal service is being resumed!

 

[Feltwell]

At my mother-in-laws house, she has a damp patch on a kitchen wall that may be caused by damp coming in from outside, but may be coming from the bathroom above. I've sorted the "outside" issues recently and am praying that does the job, as the bathroom has been in place since the 60's and previous experience tells me that all the plastic waste pipework in that house is old and brittle and doesn't like being disturbed. It could be a can of worms!

I think I've solved this particular mystery. The brickwork on an old boiler flue external to the damp area looked damp, and an old inspection cover that had rusted through had been replaced by a vent cover - but it was an internal type, and had been silicone'd into place, upside down so the baffles would cause any rainwater to run in! :roll: I replaced this with a properly mortared in airbrick, but still on the inside the damp patch was most odd. It was obvious that a patch of wall above the cooker was damp, but then the damp patch stopped at a wall-mounted cooker hood - the 12" gap above that to the ceiling was bone dry, which if the damp was coming from the bathroom above would naturally have been wet.

Mother-in-law doesn't usually cook when we visit, but on our visit last week she did - on her suitably ancient cooker. I walked into the kitchen and loads of steam was coming out past the door seals of the oven, but what she hadn't spotted (her eyesight is very poor) was that steam was also pouring out of the back of the oven and up the wall...mystery solved! :!:

 

[Zebra]

Oh dear. Poor mini-Feltwell. I suppose he'll have to wait a fair while for some new teeth, being only four.
And will your mother-in-law have to buy a new oven, or is it repairable?

 

[Feltwell]

Yes, will be a bit of a wait for new teeth. At least it was only milk teeth that he's broken. He'll have a slight facial scar but it will fade, or make him look more rugged! He's healing already, it really is remarkable how much quicker kids heal than us adults.

Much as we'd love to persude m-i-l to buy a new cooker, unless it was exactly the same as her old one I don't think we'd stand much chance. A repair - not sure. It has however a double oven, so we've persuaded her to only use the (non-leaky) bottom oven.

 

[Nigel Watts]

I have now removed the U bend. This was well fitted to the waste pipe but the fitting to the shower outflow was very loose indeed and I am 98% certain that this where the leak was coming from. Why could it have worked loose? There are also some signs of damage to the seal, possibly caused the the large quantities of acid which have been poured down the drain over the last few years to clear blockages.

The blockages may well have been caused by insufficient fall on the waste pipe. I could raise the shower tray an inch or so but would this really help on a fall of about six feet?

 

[Nigel Watts]

U bend now removed and examined:

From top left going anti-clockwise: The U bend, the seal between the U bend and the underside of the tray, the attachment to the outflow pipe, and the fitting which goes on the top of the tray and screws into the U bend.

From the black staining on the seal (bottom left) it is clear that waste waster penetrated this extensively and in two areas reached the edge, hence the leak.

 

[Penners]

I entirely agree with your analysis as to where the leak has been - on the underside of the shower waste fitting. In my (limited) experience this could be due to a number of causes:

1. Poor installation in the first place - either by being strained out of alignment or just not properly tightened.

2. Subsequent movement of the joint.

3. A less-than-perfect moulding of the underside of the waste hole in the shower tray. I had this problem recently with a washbasin - the underside face of the waste hole was not level or flat, so I had a hell of a job to get a seal. I ended up just squirting loads of LS-X into every part of the seal, and that sorted it.

When you reinstall (Personally I would buy a new waste fitting), I should coat both sides of that grooved rubber sealing ring with plenty of LS-X. If you're able to do so, I would also take this opportunity to ensure that the outflow pipe does have a fall on it. There are official recommendations for the correct fall (I don't know offhand what they are) but just so long as the water does actually flow down the pipe in the correct direction, it should be OK.

And try to go easy on the drain clearing chemicals!

 

[LadyArowana]

And try to go easy on the drain clearing chemicals!

Do you put a filter over the plug hole to make sure that hair doesn't go down? Once you get some of that in the drain it acts like a net and stuff gets blocked quite easily.

 

[Feltwell]

From the look of that waste, I presume no sealant was used where it fitted to the tray? A thoroughly cleaned tray, new waste and a smear of LSX should sort it then, I agree with Penners. I'm surprised that any commercial fitter would not use sealant - it costs next to nothing and must save them the chance of an potentially expensive return visit.

Regarding clogging, I presume this was the sort of waste where you could lift the inner section out after installation to clean it? If not I'd definitely go for one where that is possible. Ours needs cleaning out quite regularly - every 6 weeks or so - but as a result the pipes beyond the trap have never clogged. I wouldn't worry too much about the fall on the pipe - so long as there is some fall it should be OK, the trap should be the bit that clogs. If the pipe is running uphill then I can see this causing a problem with sediment & gunk at the low spot in the end, even if the water does flow.

It's always hair that clogs the trap up - when Mrs F had long hair it needed clearing regularly, when she changed to a short hairstyle it almost never needed clearing. Now that the long-haired Miss F has started using our ensuite shower (we have to almost crowbar her out - she prefers it to the one in the bathroom and takes about 45 minutes to have a shower :roll: ) surprise surprise the trap keeps clogging up again! Short of banning long haired people or enforcing military haircuts on the family I don't see a solution! :lol:

 

[Flyfisher]

I wouldn't worry about the fall of the waste pipe (as long as there IS some fall) because I can't imagine an additional inch will make much difference for all the disruption it will cause - plus, I doubt it would ever be possible to increase it enough to ensure that any blockages get washed through anyway.

The above posts are dead right about hair being a nuisance. Mrs FF's hair is long and mine is not exactly 'trim' since I retired but it is rapidly falling out, so we have plenty to stray hair to deal with and a hair trap is, I think, pretty much essential.

I would go Penners' suggestion of a new outlet with some sort of hair filter that's easily removed and cleaned from above. I'd also check the seating very carefully and also use some LS-X.

I also wouldn't put the flooring back in place for a week or two (probably months in my case! :lol: ) so that I could easily verify that the leak has definitely been fixed. Simply pouring a jug of water down the outlet is unlikely to be a good enough test; you'll need a few people to take showers with all that involves in terms of duration and movement of the shower tray and outlet fittings.

But it looks as if you're on the home straight now!

 

[MatthewC]

I'm surprised that any commercial fitter would not use sealant - it costs next to nothing and must save them the chance of an potentially expensive return visit.

Or do you mean "would give them the chance of an potentially lucrative return visit"? [/cynic]

 

[TheRoost]

I have now removed the U bend. This was well fitted to the waste pipe but the fitting to the shower outflow was very loose indeed and I am 98% certain that this where the leak was coming from. Why could it have worked loose? There are also some signs of damage to the seal, possibly caused the the large quantities of acid which have been poured down the drain over the last few years to clear blockages.

The blockages may well have been caused by insufficient fall on the waste pipe. I could raise the shower tray an inch or so but would this really help on a fall of about six feet?

No expert but compression waste fittings always seem to work loose after a while on sinks I've fitted - perhaps the rubber seals shrink? probably not the best idea for concealed areas under showers where they can't be checked and tightened.

Another advocate of LS-X here!

 

[Lime]

I'd also take advantage of the waste pipe being off to check that all the cut pipe edges are smooth and free of burrs and sticking-out bits which can catch hair and other items to create a blockage.

 

[Nigel Watts]

After three visits to the plumbers' merchants yesterday I got all the parts needed, assembled everything and eventually got a watertight fit. Shower is now on probation. If it continues to behave I will close the hole in the floor, but in such a way that it can easily be opened agin if need be.

 

[Penners]

Jolly good - fingers crossed!