Bathroom leak

RobJW · 1 Nov 2021

We had a bathroom leak a week ago. An emergency plumber came out. He found that one of the plastic tap joints had been over-tightened. The copper ring caused a crack in the plastic joint. It had been like that for 10-11 years (since we bought the house). Thankfully we caught it while it was still a drip. The plumber fitted a new plastic joint (seems to be heavier duty).

We can see a damp patch under the bath, below the tap fitting. The tap fitting is on the side of the bath, rather than at the top of the bath. A week has passed - the damp patch seems to be drying up (shrinking and does not feel wet to touch). We are not using the bathroom.

However, when we removed the tiling on the side of the bath to get access, we found a second damp patch. This damp patch is at the top of the bath, under the plug hole / trap. The plumber did some tests, but wasn't sure what was causing the second patch. He checked all the pipework and said that he thought everything was good. He suspected that old sealant around the side of the bath was the culprit.

A week on, the second patch has not dried out. It still feels damp to the touch. We haven't used the bath. I left a piece of kitchen paper under the trap for good measure, it was not wet at the end of the week. I have no idea what could be causing the second damp patch. Could anybody help with any suggestions for things to check?

RobJW · 1 Nov 2021

blup · 1 Nov 2021

The damp patch might be a saturated floorboard, or even where the water escaped when the plumber removed the trap. The paper towel didn't get wet, so just a case of leaving it to dry naturally, and checking progress. Check the ceiling below for any discolouration of the plaster, that will give clue as to how long its been soaking through.

Blup

RobJW · 1 Nov 2021

Thanks Blup, good point. There are two damp patches in the ceiling below. Sorry, I should have mentioned it before. That's how we became aware of the problem last week. Strangely, the two damp patches / stains in the ceiling below don't seem to correspond in position to the two damp patches under the bath. It looks like the damp patch caused by the faulty joint caused two damp patches (stains) in the ceiling below.

The damp patch below the trap doesn't seem to have caused a stain / patch in the ceiling below. However, now that I mention it, we have had a damp patch in the ceiling (roughly below the trap) before (several years ago). I chalked it up to the kids splashing water about at the time. I suspect that the patch below the trap is caused by bad / old sealant around the bath and a poor seal on the shower door (photo attached). The plumber didn't remove the trap, he just checked the tightness of the joint (said all the joints were good / tight).

Assuming that the patch below the trap is caused by poor sealant, then I guess the board below would have had a bit of water poured over it every day (shower usually used daily). That would tally with what you were saying about the saturated floorboard. Maybe the other damp patch is drying quicker as the floorboard was not totally saturated.

blup · 1 Nov 2021

Yes, there all sorts of ways water will find a path directly and indirectly where there is no apparent gap.

Blup

Swwils · 1 Nov 2021

If you can borrow a thermal camera it will show you the culprit right away

Togo · 2 Nov 2021

Hi, for a start you have plastic pipes & fittings to your shower mixer valve.Leaks guaranteed. I hate speedfit/ plastic fittings. Secondly your waste pipes on your bath are totally unsupported except by what looks like a zip tie. The way the waste has been fitted screams DIY job. Leaks all round unfortunately. Fill your bath, take out plug, then check underneath, you will see the leak.

Madrab · 2 Nov 2021

Togo said:
Hi, for a start you have plastic pipes & fittings to your shower mixer valve.Leaks guaranteed

How so? I quite agree that plastic isn't the best way to do it and copper is proper but guaranteed to leak .... cant agree there.
Also the plastic waste is solvent welded so should be quite secure, OK, zip ties aren't exactly the standard support method but better than no supports at all, which I see a large majority of installs that have been fitted by 'professionals', they have been in place for years without any issue.

Have to say that's all a little bit alarmist IMO.

OP ....
The bath trap can easily be checked, dry the trap thoroughly with kitchen towel, put a towel under it fill the bath and then check if it's leaking past the outside of the waste, if not then let the water go, if there is a leak at the trap itself it will become very apparent very quickly. Same with the bath edge seal, run the shower along it's length at the wall, difficult at the top if the bath now you have opened up the wall, and shine a torch along the back wall, you will see the water running down the wall, if it's leaking.

That shallow seal bath trap isn't the best quality either, probably came with the bath waste/overflow so wouldn't be surprised if it was leaking a little and could be replaced.

Togo · 2 Nov 2021

Hi, the waste is incorrectly supported meaning the weight of a bath full of water emptying will weigh heavily on the mechanical fittings at the bath waste. As for plastic or push fit fit fittings they are guaranteed to leak eventually due to expansion & contraction of hot water travelling through the pipework, it loosens the grab ring, trust me I've been to a thousand new build properties & ripped out the plastic pipework & fittings.

Madrab · 2 Nov 2021

Sorry to disagree, I've probably been to just as many new builds and existing properties over my many years in the business where plastic has been used without any issues at all. Like everything if it's been installed and tested properly then it's more than adequate IME and certainly not guaranteed to leak. One of the reasons they ask for such a high pressure test as it helps to bed the grab rings in properly. Yes, I've had to replace whole plastic systems due to leaks and invariably it has been down to **** poor installation, especially on new builds where quality is sacrificed for speed and cost. That being said I've had to re-do similar copper systems where exactly the same can be said.

Horses for courses, all that being said I will always use copper where possible.

As far as bath traps are concerned, good quality, properly installed bath traps and free flowing waste pipework will always minimise any mechanical impact from any waste run ... Again not suggesting that the pipework couldn't be supported more adequately but it is supported and I don't agree that any downwards mechanical stress on the trap from the bath's water flow will always cause leaks unless the trap and seals are of poor quality.

This isn't about differences of opinion and technical to and fro'ing as we could that all day long, this is about being a bit too broadly absolute, which plumbing rarely is.

Sorry for hijacking your post a little @RobJW

Togo · 2 Nov 2021

I probably should not have said leaks are guaranteed, but going by the pics it doesn't look like a great job. Pressure testing a new fitting does not guarantee it will not fail in the future, & in my experience, fitted properly or not, a lot of the grab rings fail over time. It's just my opinion & the fact that I hate to see Speedfit or Hep anywhere apart from the fact it looks awful & sags everywhere. Each to their own I suppose

RobJW · 2 Nov 2021

Thanks everyone for all of your comments. That certainly gives me plenty to think about.

I ran a couple of tests. Firstly. I put some kitchen roll under the trap. Then filled the bath, let it to rest a bit, then pulled the plug and let it empty. Kitchen towel was dry afterwards.

The plumber did some tests of the seal by spraying the shower round the edges. We couldn’t see any leaks.

I’ve tried drying out the floor boards below the trap with my wife’s hair dryer (I did ask!). Obviously being careful not to start a fire. I’ve done approximately 30-40 mins of that (in 5 minute spells). The wood did seem to become lighter and not as damp to the touch. I wasn’t able to get it bone dry. I’ve also put an electronic heater in the bathroom to make it like a sauna (hoping that will help with the drying out). My theory is that if I can see the wood dry out, put some kitchen paper under the trap, and then come back and the wood becomes wet again... If the kitchen paper is dry, I guess there must be something going on under the boards. No idea how it could defy the laws of gravity, but I’m at a bit of a loss for what else it could be, at this stage!!!

RonnieE · 12 Nov 2021

How long has it been exposed like that to aid drying?

RobJW · 12 Nov 2021

Hi Ronnie, for two weeks. The overflow pipe wasn’t fully tight.

Having spoken to my kids, they fill the bath very high (so water would flow down through the overflow regularly). They also use ‘bath bombs’, which I understand leaves a layer of grease across the top of the bath. I think the floorboards may be stained by the bath bomb water, which appears slightly damp / cool to the touch.

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