Copper Water Pipe Leaks

[Harold Gough]

Apparently, this is well known but it was news to us.

We live in a house converted from a bungalow in the early 1990s. The central heating pipes would be new from then. As to the water pipes, who knows?

About three months or so ago, we noticed a wet patch in the corridor ceiling and further investigation found that water was wetting the wall in a hall cupboard. Eventually, it started running to and over the house thermostat. We called in our regular plumber as I knew at least soldering would be required for a repair.

I asked him to break through the cupboard ceiling (the cheaper option) and, having done so, he could not find the leak but could hear it. Turning the water mains off confirmed that it was a cold water feed.

What I had feared was the case. It was under the bedroom floor, made of tongue and groove blockboard, held down at edges by skirting boards and door frames.

The plumber agreed to come back after I had opened up access.

After a lot of hard sawing, aware of pipes, and maybe power wiring, below, I located the leak. It was a horizontal, pinhole jet on a straight section just before a bend.

The plumber fitted a new bend and I then had to replace and patch the floor. He couldn't see the hole in the damaged pipe, it was that small!

More recently, my wife heard a hissing from our airing cupboard, which is adjacent to the bedroom. She opened the cupboard door to see a jet of water bouncing off nearby pipes and making a mini rainbow.

This was at 1am and I was woken to deal with it. It was a section of the same pipe which had been expensively repaired, several feet further along. The copper was quite dark (oxidised) compared with adjacent heating pipes.

I turned the water off and set about dealing with it. The hole was about 2mm across and a bit ragged-edged.

I used Gorilla tape bound tightly and sealed with very tight cable clips. That didn't entirely stop the flow so I tightened a g-clamp over the tape where I though the hole was.

The fix stayed dry for a couple of weeks until someone seems to have knocked the g-clamp slightly, allowing a small trickle.

I turned the water off and removed the tape. I then mixed some 5-minute epoxy and squeezed some into the hole, hoping it had spread sideways and then applied a shallow dome externally. I gave that half an hour or so to set and then applied tape and clips as previously, with the g-clamp as before.

This is a known problem with copper pipes and the recommendation is to replace them every 25-30 years. You have been warned.

Happy plumbing!

Harold

[Darkroom]

Copper piping correctly installed using best practice methods should certainly last longer than you or I will. If you had that section of pipe split down the middle so the inside wall was visible, you would most likely find evidence of cement and soldering flux. When pushing piping under a floor, it is always good practice to put tape over the open ends. On cold water pipes, residues of flux don't get washed away as they do on hot water pipes. All it needs is cement dust picked up by pushing pipes under the floor to stick to the smears of flux on the inside of the piping and a corrosive area or spot is created. Over many years this corrosive area can eat away at the copper creating pinholes and water leaks. The only answer is to remove and replace several feet of piping and hope there are no more infected areas. As you say, it is a common problem and created by poor installation methods and spilled cement dust. Hopefully it is a one off problem in your case and once a section of pipe is replaced you will not have a repeat. Replacing the entire copper cold water pipe installation every so many years is, in my opinion totally unnecessary unless the piping was installed by a troop of very untidy cement tipping monkeys.😀

Edit: In recent years this problem of pinholes in copper piping has been made more common by the introduction and excessive application of Self Cleaning Flux which is in itself, a corrosive substance where copper is concerned.

Here endeth the lecture.

[Harold Gough]

Copper piping correctly installed using best practice methods should certainly last longer than you or I will. If you had that section of pipe split down the middle so the inside wall was visible, you would most likely find evidence of cement and soldering flux. When pushing piping under a floor, it is always good practice to put tape over the open ends. On cold water pipes, residues of flux don't get washed away as they do on hot water pipes. All it needs is cement dust picked up by pushing pipes under the floor to stick to the smears of flux on the inside of the piping and a corrosive area or spot is created. Over many years this corrosive area can eat away at the copper creating pinholes and water leaks. The only answer is to remove and replace several feet of piping and hope there are no more infected areas. As you say, it is a common problem and created by poor installation methods and spilled cement dust. Hopefully it is a one off problem in your case and once a section of pipe is replaced you will not have a repeat. Replacing the entire copper cold water pipe installation every so many years is, in my opinion totally unnecessary unless the piping was installed by a troop of very untidy cement tipping monkeys.😀

Edit: In recent years this problem of pinholes in copper piping has been made more common by the introduction and excessive application of Self Cleaning Flux which is in itself, a corrosive substance where copper is concerned..

It's far from that simple. There are several possible causes, including the presence of phosphate in the water. Flux is most likely to be damaging at or near a soldered joint. Neither of ours was at a joint and both were at a distance to make it seem unlikely. The length of pipe with both leaks, granted, near either end, is entirely upstairs such that there was no need to push it through a floor.

Non-chemical causes have been identified, included flow rates, vortices, etc.

I happened to be in my local pub when a retired worker from a water company said that it was well known as a problem. I can't remember exactly what he said was the main cause but it was not flux.

Anyway, thanks for the info and I hope you are right about replacing one section, a short, horizontal part and about 3 feet of vertical, re-opening the under-floor access already used for the repair. What that does is leave a nagging doubt that we will get more of the same. However, to replace that entire cold water piping would require a whole width of bedroom floor on one side and bathroom and shower floors up. I think we will go with the former. Cutting open the ends of the removed section would be essential, for internal examination.

Harold

[Wee man]

In my area Newastle Counfy Down we have a local problem known as Newastle disease.
Lots of properties get leaks in pipes the only solution being replacement.
Cause seems to be something in the local supply, peat area at reservoir, acid water?Close by towns do not seem have the same problem, they get their water from a different supply source.
It shows as pin holes along pipes both hot and cold. Authorities wash their hands of any blame(sorry about pun)!

[Harold Gough]

In my area Newastle Counfy Down we have a local problem known as Newastle disease.
Lots of properties get leaks in pipes the only solution being replacement.
Cause seems to be something in the local supply, peat area at reservoir, acid water? Close by towns do not seem have the same problem, they get their water from a different supply source.
It shows as pin holes along pipes both hot and cold. Authorities wash their hands of any blame(sorry about pun)!

Our local water is very hard. We have a domestic softener but it will still be far from acid.

I hope we don't get any holes in hot water pipes. That would take more than turning off the mains to stop the flow quickly.

Harold

[Harold Gough]

That (curved) piece that had been leaking is about to be modified for photographic use. I have ordered a 1/4" tripod bush. I will drill a hole in the apex of the outside of the bend and screw the bush in. I can then use it as a support on the top of my trail camera spikes for low level macro, supporting the distal end, taking much of the weight of my supporting hand. It could also be attached to a tripod, or monopod, for similar use at conventional heights, where the front of the lens needs most support.

I will document this elsewhere in the forum, with images.

Harold

[Melaka]

What I like about this forum is the wide range of topics covered and the high level of expertise shown by members!

[Phill D]

I agree Melaka it's a fount of knowledge in many areas.

[Harold Gough]

Here is how I used the waste copper.

https://shorturl.at/npN17

Harold

[Harold Gough]

Another pinhole leak struck at around midnight a couple of nights ago. To cut quite a long story shor*t:

All the following was with the mains turned off

I had hoped to block the hole with a tiny brass screw with epoxy cement on its thread. However, with the hole 180degrees away from me, maneuvering a tiny screw into the hole and then using a screwdriver left handed while reaching into the hot water tank cupboard was not going to work.

Looking around at the variety of metal bits I had, some drawing pins flaunted themselves. One fitted the leak hole hole fairly well. A new plan formed.

I roughed up the shaft of a drawing pin with abrasive. Then I soldered a deliberately ragged piece of solder to its tip, while keeping it narrow. This was to make it less likely to slip out of set glue.

I then covered the shaft with fast setting epoxy, eased it into the hole and held it while the glue partially set. I then filled the space between the pin head and the pipe with more epoxy, eased the pin in until flush and tied a cable clip around pin and pipe to hold it in place, as it remains.

I then turned the water on briefly to see if there was a seal and then turned it off for a couple of hours to let the glue harden more.

Job done but I have asked a plumber to replace the section of pipe with the two pinhole-prone ends.

The rather poor photo shows the finished repair.

* This was the final repair, omitting the details of the temporary one.

Harold

[moggi1964]

Had the same thing happen to me a couple of weeks ago. Kitchen floor was pretty wet and it was evident the water was coming from above. I lifted the floorboards and could hear the water spraying out. Local plumber replaced the section of pipe for £30.

I will need to get some plastering done though and some repainting.

[Harold Gough]

Had the same thing happen to me a couple of weeks ago. Kitchen floor was pretty wet and it was evident the water was coming from above. I lifted the floorboards and could hear the water spraying out. Local plumber replaced the section of pipe for £30.

I will need to get some plastering done though and some repainting.

I wish I had your plumber. Ours is very good but expensive. At least I will be lifting and replacing the floorboards.

Harold

[blu-by-u]

Over here it's the poor quality of those copper pipes. (They tend to split at the seams.) About 15yeqars ago, I replaced my incoming with Stainless pipes, but the plumber cheated. those sections that I could not see, under the roof, were poly pipes and worst, they were not of high quality. Over the weekend, a drip from the joint started. it's is the 4th joint that gave way. Si this time, I had the whole thing changed. from the end of the stainless pipe to the outlet in the kitchen. Cost, £250. and a whole days work. Hopefully, it will be peace for the next 15 years.