Copper pipe in concrete

You need to insulate the pipe. While the cement is curing, it attacks the copper. Standard pipe lagging will do the job.

Yes and no respectively. Denso tape is usually used, although I have laid copper tube inside PVC conduit when that was all I had.

Colin Bignell

On Thursday 09 May 2013 18:10 Gordy wrote in uk.d-i-y:

Protect it without doubt.

2) If the pipe wants to expand and contract it will eventually end up rubbing itself to death.

The "old way" was wrap it in denso tape.

You could (and I would) slide it inside a bit of plastic pipe. Plastic water pipe would be a good choice - it would allow a gentle bend for the pipe to come up both sides. You could even replace the pipe in the future if needed.

Protect it. Concrete attacks copper pipe.

So why not just use plastic pipe in the first place:-)?

It needs protecting. IIRC it will fit nicely inside some 15mm speedfit pipe. You could just use speedfit.

Expansion and contraction plastic is a lot softer than copper... And I think plastic expands more than copper as well.

How about plastic pipe with a wrapping of something like, umm, pipe insulation? After all, the OP possibly doesn't want to lose heat from the pipe into the concrete floor. (Depending on circumstances - appreciate sometimes it would make no difference.)

On the other hand, each size of plastic pipe slips quite happily through the size above, making a very convenient conduit and giving protection and insulation (not that I've done this through a floor, only through walls!)

On Thursday 09 May 2013 19:19 ARW wrote in uk.d-i-y:

Then you couldn't replace it :)

concrete made with flyash attacks Cu, sand/opc doesn't. Long runs get into trouble with thermal expansion if not sleeved.

If ground floor, insulate it.

NT

wrap it in DENSO tape