Which pipe for under-concrete CH - Plastic or Copper?

[kannit]

Hi,

We currently have copper pipes under concrete screed which is leaking at few places (CH pipes) so we are considering to replace the whole lot on ground floor. But need to take a decision - Plastic pipe (like Hep2O) or Copper?

1. Is Plastic reliable for under concrete installation? What kind of problems it can pose?
2. Is copper pipe walls thick enough these days?
3. If we use copper, how can we protect it best from corrosion?

Thanks for your comments!

 

[Howsie]

You don't want any joints under screen so plastic is the way to go although it can be done in copper if you know what you're doing. How it's done depends very much on what sort of run it is and what the pipes are being used. You will need to insulate and allow for expansion and contraction to ensure that the pipes don't rub and leak all over the place.

My advice to you, don't do this part yourself. Get someone in who knows what they're doing. That way the responsibility is with them if it goes pair shaped and you need to dig your floor up.

 

[kannit]

Thanks Howsie - I'll be using a plumber definitely.

You're right that there will be less number of joints with plastic but there will still be some, isn't it? How do plastic fittings at joints hold up under concrete?

What is the best insulation in the market? And what is the best practice to allow for expansion or contraction when pipe is under concrete floor?

 

[Howsie]

Thanks Howsie - I'll be using a plumber definitely.

You're right that there will be less number of joints with plastic but there will still be some, isn't it? How do plastic fittings at joints hold up under concrete?

What is the best insulation in the market? And what is the best practice to allow for expansion or contraction when pipe is under concrete floor?

Do have to have joints at all sometimes when it's designed correctly. Shouldn't really have any buried fittings. Insulation depends and expansion is dependent on the material being used. Choose the wrong insulation and it'll eat the pipe or react with the screed etc.

If you're using a plumber, he'll know all this anyway so don't sweat it. Let his brain take the strain.

 

[ShaunCorbs]

As above and I would use armoflex or do it in some 2" waste pipe if you have the dept

 

[lame plumber]

best of all use a duct and then if need be you can replace any problems

 

[Gary80gas]

If you bury plastic push fit fittings I would wrap the fittings well to protect from any cement getting into end of fitting. Years ago there were some problems with screed laying causing leaks and they were designing rubber covers for fittings, don't know if it got anywhere.
If you use copper wrap in denso tape but beware oils leaching out. Ive seen new pipework dug up because the tape oils looked like a leak staining the fresh concrete.
I recently replaced some copper in concrete only 15yrs old wrapped in electricians tape, the pipes were rotten and would have been nearly new if proper protection had been used.

 

[kannit]

Although I'll be using a plumber for the job, but I understand there is no common practice among plumbers for doing same work. So I don't know how my plumber will do it exactly.

Since I've got only one shot at it to do it right and also will be spending good deal of money (got one quote for 1800 quids), I have to get it done in best way possible.

I've following options in my mind
Option 1. Use copper pipe (PVC coated preferably), run them inside a duct, conceal the duct with sand before flooring.
Option 2. Use uncoated coper pipe, insulate with high temperature armaflex insulation, conceal with sand before flooring.

Main aim of these approach is to:
1. Provide compete insulation from concrete
2. Ensure there is enough room for pipe expansion
3. Reduce loss of heat

I personally prefer option 1 but open to more suggestions.

Thank you

 

[ShaunCorbs]

Have a look at pex pipe in a pipe sleeve

 

[kannit]

Read somewhere:

Use 10mm plastic inside plastic conduit to each radiator, so no joints are needed in the floor. A manifold will then connect each circuit.

ShaunCorbs - Do you mean same, and which brand pex?

 

[ShaunCorbs]

Read somewhere:


ShaunCorbs - Do you mean same, and which brand pex?

slightly, from new i wouldn't even put 10mm in 15-16mm all the way as long as you can get back to your main runs (22mm circuits)

and pg 22

https://www.google.co.uk/url?sa=t&r...z17PXSUNfvgPJK8BjIZ8iw&bvm=bv.116274245,d.bGg

 

[Howsie]

There is a common practice amount plumbers and it all depends on what you're trying to achieve and what the house layout etc is like. I've attended many jobs where a customer has tried to do this themselves and have either contravened the water regulations or ended up with water lifting their lovely wooden or tiled floor. The rub with this is, if you've installed this yourself your insurance company may not pay out if you come to claim.

And if you laying or going near potable water don't forget legionella prevention.

Good luck.