Copper pipe in Concrete

[Will Billy]

Yes - I know this has been done to death, but its still not quite clear to me - do the pipes only have to be protected from new concrete? Or will say, 25 year old concrete floors still corrode the pipes?

I'm only asking because I had a plumber install a new heating system in my flat, and there are a few channels that have been set into concrete for the central heating pipes and gas pipes. The guy only covered the top half and some of the sides with Denzo tape (which I note gets mixed reviews anyway). I wary that when I come to fill the gaps, even if I use a dry mix, some might find its way to the underside of the pipes.

I also read somewhere in here that gas pipes aren't even supposed to be covered with Denzo tape? I'm just trying to get the facts before I go saying that the plumber hasn't done his job properly...

One other thing - copper is supposed to be corroded by concrete, but I have uncovered copper pipes set in concrete in my flat that are still working perfectly. They are not covered in anything, and must have been there for at least 25 years....

Appreciate any help with this, cheers

 

[gas4you]

Apart from the corrosion factor, which is probably debatable on existing set concrete, I would be concerned at the movement factor of copper against concrete and any possible rough edges that could rub and cut into the copper on expansion and cooling

 

[giblets]

I was under the impression that, according to the Water Regs, all new pipes in solid floors had to encased in channels with removable covers. The gas pipes must certainly be installed by using purpose made plastic covered tube with no joints in the floor

Your installer should certainly have wrapped the whole pipe in Denso tape not just the top and sides. Sounds like he put the tape on after the pipes were put in the chases. Did you find any hoof prints on your drive when he finished?

25 years ago the copper pipe was thicker than it is today. Also, how do you know that the existing pipework had not been protected with bitumen paint before covering up?

 

[Bahco]

Did you find any hoof prints on your drive when he finished?

Nice one

 

[Will Billy]

Thanks for the advice guys. I hadn't really considered the forwards and backwards movement from heat changes.

As for the gas pipes then, I'm basically looking at somehow getting plastic piping over the gas pipe - which of course won't be possible without getting it disconnected?

Interesting about the copper pipe being thicker 25 years ago, and yes, I can't actually tell whether they have been covered in bitumen or not (although it doesn't look like it to my untrained eye)

Just checking for hoof prints...

...think I found a couple

 

[Breesey]

As for the gas pipes then, I'm basically looking at somehow getting plastic piping over the gas pipe - which of course won't be possible without getting it disconnected?

How long is the gas pipe run?

You could slit some lengths of Hep (22mm if it's a 15mm gas pipe) so that you can then slide these over the gas pipe with out disconnecting it. That way it's protected and would have room to expand when covered up again.

 

[Agile]

Different regulations apply to different types of pipes!

Heating system pipes can be installed just as you like but then there is good practice.

If pipes are burried in concrete then allowance needs to be made for expamsion.

Corrosion usually needs water present as well. If this is above ground floor then there is little risk but if its ground floor then the risk is much higher as some dampness is likely to be present.

With good practice all CH pipes will be wrapped or better insulated which allows expansion as well as movement.

Special regulations apply to mains water supply pipes and to gas pipes.

Tony

 

[easydes]

with no joints in the floorquote]

how on earth are you supposed to run a carcuss for a house in copper with no joints!

if its for gas run it in sleeved copper and when you have to join then wrap in denso over the join. if its normal heating or domestic pipework then sleeve in hairfelt lagging so it gives some protection and gives it room to expand and contract!

 

[corgiman]

with no joints in the floorquote]

how on earth are you supposed to run a carcuss for a house in copper with no joints!

if its for gas run it in sleeved copper and when you have to join then wrap in denso over the join. if its normal heating or domestic pipework then sleeve in hairfelt lagging so it gives some protection and gives it room to expand and contract!

giblets probably meant no COMPRESSION fittings under the floor