What is the correct way to bury central heating pipes

[RayPlumb]

I have a system that pipes under screed keeps leaking. Looking to replace under floor pipework to 5 radiators under screed and 3 radiators with pipework under false floor.
I have already rerouted water supplies above screen. To rerun all pipework from above droping down into rads would be problematic as i would have to upsize a lot of the pipework upstairs, and they have just had all new carpets and decorating done upstairs.
Can you still insulate and bury or do whey have to be boxed in.? Floor is to get leveling compound then cardine flooring when finished.
Thanks
Ray

 

[Chalked]

Most leaks on copper under screeds, is due to expansion. As the copper is fixed where it comes out of the screed, it has no movement. This then transmits the forc into the fitting, which then over time leaks. Care should be taken when doin an install like this to minimise the length, change direction often, allow lateral movement and if need be, install expansion bellows.

 

[AWheating]

Pipe in pipe or in a duct ideally

 

[king of pipes]

I would use a manifold system in Kuterlux plastic coated copper or as suggested above hep 2o pipe in pipe you would have no joints buried in the screed regards kop

 

[Chuck]

Some useful info from the CDA:
Plumbing: TechCorner - Is There A Problem With Embedding Copper Tube In Concrete?

 

[Gareth Harris]

This is clearly quite a difficult one.

The CDA certainly suggest that embedding pipes in concrete is acceptable.

However, legislation suggests otherwise in terms of embedding: The Water Supply (Water Fittings) Regulations 1999

There is further clarification here: https://www.wras.co.uk/downloads/pu...eral/para_7_guidance_version_2_july_2014.pdf/

As others have suggested, pipe in pipe or a manifold system and no joints. In an ideal world it wouldn't be in a screed!

 

[tolly]

That doesnt mention that your not allowed fittings under the floor (inaccessable) be it solder or mechanical (compression) stated by water regs...not that many people take any notice of that.

Plastic Pipe in Pipe with manifolds are good but you still have to have a fitting under the floor if you want to turn the tails up in copper.

 

[tolly]

Ive just seen this is heating pipes, in which case water regs doesnt apply to it so you have it in copper with soldered fittings.

 

[Welder]

Hmm. So why do I see so many pin holes in copper buried directly into plaster and concrete? I was always told they were to do with the copper reacting with lime... Love to learn

 

[tolly]

Yes you still cant have the copper in direct contact with screed or concrete, needs to be plastic coated or wrapped in denso tape. Hair felt lagging is also no good.

 

[Welder]

So that's very misleading.

The article linked to above FAILS to state categorically that pipe should be covered. All it seems to infer is that room should be made for expansion!

 

[Chuck]

Hmm. So why do I see so many pin holes in copper buried directly into plaster and concrete? I was always told they were to do with the copper reacting with lime... Love to learn

Unless concrete has a high chloride content, e.g. because it's been made with beach sand, it is asserted by cement manufacturers that it doesn't corrode copper.

There are lots of known reasons for copper corrosion, see this review by the Foundation for Water Research for an interesting discussion:

http://www.fwr.org/copper.pdf

but 'reacting with lime' isn't listed. The most comonly encountered ones are plumbers using aggresive fluxes and not cleaning residues, cheap tubing (esp from the 70s) with low grade copper and/or thin walls, and high flow-velocities.

Where the alkaline environment of concrete/plaster does appear in this review it is as one of the several factors needed for stress-corrosion cracking (longitudinal cracks) to occur.

 

[Welder]

Than you for that. Very informative. Let me now ask you a simple question. Would you bury a copper pipe directly into concrete or plaster?

 

[Ant Parkes]

Than you for that. Very informative. Let me now ask you a simple question. Would you bury a copper pipe directly into concrete or plaster?

I certainly wouldn't. For the time it takes to tape them up why wouldn't you?

 

[Chuck]

Than you for that. Very informative. Let me now ask you a simple question. Would you bury a copper pipe directly into concrete or plaster?

No. I like my pipes to be in ducts and/or insulated as appropriate.

Anyway, enough people believe that copper can't be left bare in concrete or plaster that it is conventional to sleeve even when theoretically unnecessary. In practice, any leaks that did occur otherwise would probably get blamed on the lack of sleeving, etc. even though it's not certain to be the root cause.

Why take the risk?