Leaking copper pipe

[Keefiedee]

Have discovered a large area of wetness in the kitchen ceiling and down the wall. The bathroom is above - more particularly the bath itself. There are the hot and cold feeds to the bath runniing along parallel to the wall just above the plaster and just less than an inch away from it, with a 4" waste pipe a couple of inches above them running along to the stack pipe at the end of the bath.

Thought I was going to have to take the bath out to get at the problem, but then had a brain wave and cut away the ceiling plaster parallel to the wall in the kitchen that runs under these pipes. I find there is a moderately slow drip coming from a point at the near the base of the low pressure cold feed pipe to the bath (which for some bizarre reason is 28 mm pipe). There is no sign of any trauma to the pipe at what seems to be a very localised point of leaking, no scratch or sign of a nail having been inadvertantly driven into the pipe

Is it at all possible or likely that a piece of copper pipe could have a thin section which could eventually leak over a period in time in the absence of any trauma to the pipe? I'm wondering, if that is possible, whether I should replace the whole pipe, or just the piece that is leaking.

Thoughts please.

Keith

[Phil L]

Is it leaking from a joint? Have you checked that it's not leaking further away from where it's dripping? - water finds the lowest point and it could be that the lowest point is where you are seeing the drips. Other than that, if it *is* in the middle of a section then it's frost damage and it must have been like this for about 6 months before you noticed it.

[Andy Dingley]

Possibly uncleaned flux residue from a soldered joint years before, now having eaten through and pinholed the pipe.

[Keefiedee]

Not leaking from a joint, and pipe is horizontal and is now dry on either side of the drip now I have opened it up and got air to it all, so I'm pretty sure it is a failure at that point. I don't think it could be frost damage as it is not in an exposed position and wouldn't barely be any colder than the interior of the kitchen and bathroom are, and they were heated and thus frostproof all winter. There is a soldered jont about 2 feet "upwind" of the leak, but that would have been done perhaps 10 - 15 years ago - would it take that long?

Keith

Keith

[Roger Mills]

How sure are you that it's definitely the pipe itself which is leaking? It's more likely that a joint is leaking slightly higher up, with the water running along the outside of the pipe and dripping at the point where you assume the leak to be. The water could even be coming from the waste pipe.

[Keefiedee]

Absolutely certain. The points you make are very valid, but, as I have mentioned already - the pipe is absolutely horizontal and is now completely dry on either side of the leak. And the waste pipe seems totally intact with no sign of water dripping from it. In any case, the waste pipe would only be carrying water to drip from occasionally, when someone is using the shower, and this drip is absolutely constant. That was why I posted in the first place - because I found it hard to belive that a copper pipe could be leaking like that for no obvious reason.

Keith

[Keefiedee]

As previously mentioned, I have absolute certainty where this leak is coming from, and it is not the waste of down the side of the bath. I am actually watching a regular drip - drip - drip from one very localised point on the pipe.

Can anyone give me a link to slip connectors so I can see exactly what you're talking about please? That sounds the answer, and I won't have to call a plumber out - just a plasterer to replace the ceiling!

Keith

[Keefiedee]

Are slip connectors available as compression fittings or only soldered?

Keith

[Phil L]

Is the wall they are near an outside wall? - if so there is a hole in it and the pipe has frozen.

I have never known copper pipe to be 'eaten' away by flux, and I seriously doubt this could occur in 10-15 years anyway, and not without a large patch of blue/green corrosion being visible around the leak.

I've seen dozens of pipes freeze in exactly this position, between kitchen and bathroom, and it's always the same culprit - a hole in the brickwork

[Cicero]

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I've only seen 15mm slip connectors (compression) so you might struggle to find them for 28mm. There are various repair kits available but they tend to to be a bit unreliable for long term use. It would make sense to cut out the whole section of pipe at convenient points and replace with new smaller pipe unless there's a good reason for retaining 28mm.

You can make your own slip connectors but it's a bit tedious so replacing as I suggested is easiest as you can usually choose the most convenient places too cut.

Ci.

[The Natural Philosopher]

Yes. Pinholes due to impurities in the copper form pinhole corrosions is not unknown, though I have personally never seen it.

I'm wondering, if that is

There is another possibility. Happened to me one very hot summer when I was tiling the kitchen.

I paused and heard a steady drip drip drip from..the cold water pipe.

Water was pouring off it.

Ok I thought, new build. Bad joint. So I turned the mains off. And opened the cold tap. No pressure. Properly off. Drips continued.

THEN I realised I was using about a gallon an hour of water to mix tile cement, and making the air humid as **** in the process. The cold water pipe was kept p[permanently cold, and condensation was rampant on it!

So check for that..easiest is PROBABLY to wrap pipe in a towel. That will insulate it a bit and stop direct airflow. If that comes off a day later wet inside, you have a leak,. If it comes off generally a bit damp, or dry, its condensation, and the cure is to insulate the pipe with a bit of split foam tubing, and use foil backed plasterboard to repair the hole you made.

If the pipe IS pinholed, replace as much as you can. Its like rotten wood. The real cost is the labour, so might as well dump anything suspect. Scrap copper still worth taking in for money.

[The Natural Philosopher]

It might happen in a sealed system like CH, but not in a much used cold water feed. That will have washed any flux out a long time ago.

I've only ever seen three pipes freeze. Oner was in my porch, sub zero for a week. One was in my roof, left without heating in the house for 2 weeks in winter just before I demolished it, and the other was attached to an outside tap.

[The Natural Philosopher]

with luck, there is enough leeway ijna compression joint to be able to fit it without it being specifically 'slip' bit I would definitely reach for the torch here, or cut back to somewhere that compression will work easily.

[tony sayer]

In article , Keefiedee scribeth thus

Can you take a picture and post it somewhere, sometimes a Pix is worth a thousand posts;!...

[newshound]

As others have said, the proper fix is to cut out and replace. That said, if access is difficult, that "plumbers" epoxy is remarkably effective. Comes as a stick with the two parts, you cut off a suitable length and work it as if it was plasticine, then stick over the hole. It won't seal while the pressure is on, but it will seal on to wet surfaces. I've only ever used it once (on a hot water cylinder joint, *very* inaccessible) but it survived for years and saved me a pile of work. If your problem is a one-off, it is a quick cheap fix. If there are potential pinholes all along the pipe just waiting to appear, you should be replacing. Of course the only way to find out is to just fix the current problem!

[<me9]

When I had a similar problem it was the bath overflow (where it attached to the bath) that was leaking.

I have seen copper pipe corroded through from the inside, but carrying purified (but open to atmospheric CO2) water at high temperature and flow for nearly two decades 24/7. Can't see it happening in domestic.

[dave]

To test this, go to your local supermarket and see if they have any blue tissue on a roll to wipe the trolley handes and put 3 sheets in your trolley before you do your shopping. When you get home try wiping the pipe above where the leak is and if it is wet, the colour will darken.

Dave

[Spamlet]

What people are saying about 'pinholes': the drawing of the pipes through a dye can drag out any impurities into long flaws like dark scratches all down the length of pipes. Sometimes you will see whole bundles of new pipe like this in the 'sheds', where they - as with their timber - are not that bothered about the quality. If you have a pipe like that it would be best to replace the whole thing.

On the other hand, nobody has mentioned the Speedfit flexible couplings: possibly as I can't see any 28mm ones. On the other hand there is the even easier rubber connector and jubilee clip option: if it's good enough for cars it ought to be fine for water in the house:

.

A whole new piece of copper pipe would still seem the best idea though.

S

[PeterC]

Now, this was on a DHW pipe: in and above kitchen, approx. 50 years old, exposed to cooking fumes all of that time. Not often hot, so condensation could form. Boiler fitted, DHW now on mains pressure, couple of I've seen dozens of pipes freeze in exactly this position, between kitchen