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Discuss Burst pipe under screed mystery in the Plumbing Jobs | The Job-board area at PlumbersForums.net

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Hi All

I wonder if you could help me with a small conundrum. I was recently called to the scene of a water leak in a bathroom installation that we carried out a few years ago. I will try to include as many as the details as I can.

The homeowner had walked in to the bathroom and found water had suddenly risen up from under the tiles. An emergency plumber from British Gas was called (on their home insurance scheme) and he broke out the tiled floor and screed, found the source of the leak, cut the 15mm copper pipes which teed of from a 22mm pipe (all under the screed) and which went on to supply the bathroom radiator and capped them. He then repressurised the system to confirm the leaks were on the 15mm side and the heating is now working again minus the bathroom radiator.

This is when I turned up to view the scene. It was apparent that when the original bathroom install was done, an existing radiator was removed, its 15mm supply pipes excavated and jointed with hep20 fittings, run in hep 15mm pipe under the screed (joints and pipe under screed) up into a new stud wall to serve the new rad. What would not have been apparent to the original plumber and was only discovered by the actions of the emergency plumber digging up the screed was that the 22mm pipe was in fact a 1 pipe system, as both 15mm copper tees came off the same pipe. I inspected the hep to copper connections and they were taped up to protect from the screed and the 15mm copper had been well rubbed down and polished before connection. The plastic pipe connections had used the metal inserts. Looking at the pattern of the water staining it was clear that the leak had occurred around the area of these connections and so on balance of probability it was probably these that leaked as opposed to an old degrading copper pipe.

My first thought was that the fault lay with the plumber for using hep connections under the screed. But I then pondered that although push fit has a bad reputation with some people, in my experience leaks can normally be traced back to user error (inserts/scratched pipe ends/not pushed home etc). The plumber who installed this pipe is meticulous with such things and we have never previously had a problem with Hep20 before, so it sat uneasily with me as an explanation. The screed patch was small so should not have put undue pressure on the fittings through expansion and contraction.

I then overheard the emergency plumber talking to the homeowner about the fact that the pressure gauge on their new combo boiler had failed and that he would come back and replace it. This however was an afterthought and he did not connect this to the work he had just done.

I don't have enough plumbing knowledge to form a authoritative view on the cause but I do have to invite someone to accept responsibility, plumber/householder/British Gas? In the end liability may lie with me as installer simply because its not clear what the cause of the leak was, but some guidance by experts would be most welcome!
 
This looks a bit dogey to,moi
...I would walk away ..its aBG
problem not yours ...I can see loads of problems and no money out of this one for you
you might even be better off taking the day off rather than getting involved ..I have learned to be totally binary in this industry which I actually love having spent 40 years at it ...61 yesterday still going strong ..Rob Foster
aka centralheatking
 
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Hi Simon, I was the original installer/contractor, although my subbie at the time carried out all the plumbing works. I was therefore called back as having liability for any failures and putting them right.
 
This looks a bit dogey to,moi
...I would walk away ..its aBG
problem not yours ...I can see loads of problems and no money out of this one for you
you might even be better off taking the day off rather than getting involved ..Rob Foster
aka centralheatking
Would you "walk away" from one of your jobs Rob?
 
I don’t really get what the question is are we commenting on what caused the leak?
 
Can't walk away, client is a vulnerable person and it has to be done right. I will carry out the making good at my own cost as on balance of probability it was 'my' fitting that failed. But I would still like to understand the cause and if appropriate let the client know what I think happened.
 
My warranty is if it fails in an unreasonable time and causes damage I'll make it right, unless I can point to a manufacturing fault that it is clear and beyond my control. In this case I know what Hep would say when I tell then the joint was under the screed.
 
As a fix I'm going to go back to the boiler and bring two new flow and return down a stud wall to get to the radiator and leave the original copper pipes capped in the screed, which in hindsight is what should have been done in the first place although considerably more work. I also definitely would have done this originally if I had known it was a one pipe system as I don't understand them. However that still leaves me curious about why it failed.
 
Yes my subbie put the Hep fittings (old 15mm copper - hep20 fitting- hep20 15mm) in the screed, and yes my first thought also was that was why it failed. However in hindsight I don't know why this should automatically be assumed as the I cannot think of a reason why it should fail in screed and not in a stud wall void.

I can understand if it was a new large screed floor because the contraction over time of the screed can cause large movements which might put pressure on the grips and seals between the fittings and pipe. But this would not occur with small screed patches as in this case. I also thought about whether natural expansion and contraction of the rigid plastic fitting in a confined screed could cause a fracture, but then 2.5 years is a long time for this to wait to happen.

What I also wondered was whether the failure of the pressure gauge might cause the homeowner to read zero pressure, and then ramp up the pressure to maximum mistakenly believing that the pressure was not rising. This might cause the weakest point in the system to fail. In an all copper system this could be the plastic to copper joint, but if this had not failed, next would have been a copper joint.
 
Screed will get into the fitting and onto the seals air in a void won’t. Think you’re clutching at straws a bit with the pressure thing as most plastic is good up to 10 bar
 
All joints were well wrapped to prevent any contamination from cement in screed. Did not think about the PRV opening at 3bar. Could it be anything to do with 1 pipe system, that was the other coincidence, first time a Hep20 joint has failed on me and first time I've had dealings with 1 pipe system?
 
I think the main issue here is
the ...sub contractor whom has not carried out the work properly...only the main contractor is really to blame and as always carries the can.
Contract and subby management is a hard learned skill no matter how good the main man might be .

Rob Foster aka centralheatking
 
Yes my subbie put the Hep fittings (old 15mm copper - hep20 fitting- hep20 15mm) in the screed, and yes my first thought also was that was why it failed. However in hindsight I don't know why this should automatically be assumed as the I cannot think of a reason why it should fail in screed and not in a stud wall void.

I can understand if it was a new large screed floor because the contraction over time of the screed can cause large movements which might put pressure on the grips and seals between the fittings and pipe. But this would not occur with small screed patches as in this case. I also thought about whether natural expansion and contraction of the rigid plastic fitting in a confined screed could cause a fracture, but then 2.5 years is a long time for this to wait to happen.

What I also wondered was whether the failure of the pressure gauge might cause the homeowner to read zero pressure, and then ramp up the pressure to maximum mistakenly believing that the pressure was not rising. This might cause the weakest point in the system to fail. In an all copper system this could be the plastic to copper joint, but if this had not failed, next would have been a copper joint.

You can sit and analyse this for hours, but plastic fittings in screed DO fail.... that’s why they say not use mechanical fittings in screed. I believe it worked it self loose due to contraction / expansion, the constant heat cycle eventually caused either a stress fracture of pushed the fitting off, different materials have differing expansion rates and create immense force. I don’t really care if your contractor is meticulous in his work ethos, he carried out a something that is not the norm to how professionals do things.
As had previously been said....’Rubbish happens’ and your tackling this problem perfectly with the customer and taking it on the chin.

And finally, anything I put in a screed or walls or underfloor, get pressure tested to confirm tightness.
 

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