Burst pipe under screed mystery

[Rob Foster]

I think his contractor fitted it in the screed on to the copper.

uck

 

[Daniel Adams]

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.

 

[Riley]

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

 

[Scott_D]

Hep should be tested at 10bar
The boiler prv should open at 3bar so this shouldnt have caused the leak

 

[Daniel Adams]

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?

 

[Rob Foster]

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

 

[Sharp Point]

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.

 

[Daniel Adams]

Thanks everyone for comments, definitely helped me think through things.

 

[Harvest Fields]

More than welcome mate.

 

[Daniel Adams]

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

Definitely agree with that

 

[1Steven]

Sounds like one you put down to experience, go on you for seeing it through. Thoses joints need a bit of room for expansion so they form a thight seal.

 

[sammathias]

I wouldn't accept responsibility of something that was installed over 2 year ago and had now failed ..