# Forum Home Renovation Plumbing  Copper pipes in concrete?

## Smiley Guy

Somebody told me that cement can sometimes eat into copper pipes (for hot & cold water). They also said there is a special tape you can get to put around them to protect the pipes. Is this correct? Can I just use plain plastic sheet? I am chasing some pipes into a brick wall where they will eventually be cemented into place.

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## ozwinner

I think some one is pulling your chain.. :Doh:  
Al  :Biggrin:

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## DJ's Timber

The only concern I would have is to make sure that the pipe can't move or rattle after it has been cemented in place. 
I have had to jackhammer some of the concrete out of my folks place to fix some leaks that was soaking up through the carpet. One section of pipe was rubbing on a stone in the concrete, cause the concrete hadn't been vibrated and there were a lot of airgaps around the pipe

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## bitingmidge

> Somebody told me that cement can sometimes eat into copper pipes (for hot & cold water). They also said there is a special tape you can get to put around them to protect the pipes. Is this correct? Can I just use plain plastic sheet? I am chasing some pipes into a brick wall where they will eventually be cemented into place.

  Rest assured that eventually the copper WILL corrode if encased in concrete, the last time I dug out pipes chased in brickwork was in my daughter's unit, and it took 21 years for the shower combination to spring a leak. 
DON'T listen to the bricky! :Eek:   
Normal plastic packaging tape is fine, but it's easier just to use lagged pipe (the stuff with the plastic insulation round the outside).   
I don't allow cast-in pipes on any of my jobs UNLESS it's in conduit and can be replaced WHEN it springs a leak.  This isn't always possible in situations like yours, so go for it! 
cheers, 
P

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## bsrlee

Largely what Midge said. Copper pipes direct into concrete = leaks in a few years, ruined carpets etc. & a PITA to replace.  
The 'old' way to fix this was to make a trench in the concrete & lay the pipe in sand, cover it with sand & then cap with cement - builders were just laying the pipe (and 240 volt cables) bare in the floor & walls, tied to the reo, and pouring over the top. 
I've seen a lot of copper pipe with what looks like green plastic water hose covering it - I think that is the 'special tape' that has been mentioned to you that will somehow stop the pipes from leaking.

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## John99

Hi Smiley Guy  
I had a natural gas pipe that was in concrete and where it came out of the concrete it corroded and I had one big gas leak  :Shock:

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## ozwinner

I think if youse all look he is going to encase it in mortar which a whole lot different to concrete. 
I assume it will be mortar as its going in a brick wall and I thought Id let Jethro :Roll Eyes (Sarcastic):  off with calling it cement. 
Nearly all concrete contains retarder, which is very corrosive.  :No:  
Al  :Sneaktongue:

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## Smiley Guy

Thanks guys - I think I might ask at the plumbing supplies store after your advice - just in case! 
I'm not exactly sure if I'm using 'mortar'. It's an existing wall in which I have already chased the channels out for the pipes. I will fill it in (after I put pipes in) with a sand cement mix ( a weak one in case I ever do have to get to the pipes!) 
Is that what you are calling mortar? My title is confusing.

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## ozwinner

> Is that what you are calling mortar? My title is confusing.

  Thats it!! 
Al  :2thumbsup:

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## journeyman Mick

Sorry Smiley and Al, I've had to open up walls where pipes and combinations had been chased and mortared in and they had corroded. Admittedly this was after 25 years or so, but it does happen. Not all of the pipes corroded (large commercial building with 8 bathrooms) but about half have needed attention so far. Of course, if you have internal brick or black walls it's a bit hard to avoid altogether, but using lagged pipe and then lagging the combinations and breeching pieces will go a long way towards avoiding problems down the track. 
Mick

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## Barry_White

When you go to the plumbers supply just ask for lagged copper pipe. It has a foam type lagging around the pipe, varies in colour sometimes green colour sometimes orange colour depending on the manufacturer of the copper pipe. Copper pipe comes in two grades, hard drawn which you can't bend and soft which comes in coils which you can bend which ever way you want.

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## ozwinner

> Sorry Smiley and Al, I've had to open up walls where pipes and combinations had been chased and mortared in and they had corroded.  
> Mick

  Mick everything up your end of the country corrodes, when I was up there some years ago I even had my nether regions starting to corrode.  :Shock:  
Al  :Biggrin:

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## Cliff Rogers

> ...had my nether regions starting to corrode.  
> Al

  Happens if you don't use it enough Al.  :Wink:

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## Smiley Guy

I have already cut and soldered most of the pipe (well Dad has - that's what they're there for right?) - can I buy some 'lagging? What's it called?

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## Tools

foam lagging.You can buy it in rolls. 
Tools

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## rrich

FWIW, I had a house built on a slab floor. Our pipes ran through the slab and were encased in a neoprene tube (or, excuse the word condom). I was told by the plumber that this was to prevent corosion. The plumber also said that they used soft copper pipes so that there were no soldered joints below the slab.

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## Barry_White

> foam lagging.You can buy it in rolls. 
> Tools

  I think you would find that type of lagging would nbe too bulky to be chased into a wall. The prelagged pipe has a lagging that is only about 3 to 4mm thick and is much denser than the after the event lagging. 
Probably the best thing to do would be to get some grey duct tape and wrap the pipe with it.  
Shouldn't take more than an hour to accomplish that.

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## bitingmidge

> I think if youse all look he is going to encase it in mortar which a whole lot different to concrete.
> Nearly all concrete contains retarder, which is very corrosive.

  And "nearly" all (depending on your brickie! :Wink 1:  ) mortar contains cement, which isn't at all corrosive!.  :Doh:   
Sorry Al, I've dug out too many to let you get away with it!  
Cheers, 
P  :Biggrin:   :Biggrin:   :Biggrin:

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## Smiley Guy

Thanks guys, 
Very glad I asked. The foam stuff would be too bulky in what I have chased out in the wall. I'll go to the shops and ask for some thinner stuff this week hopefully. 
I was going to to it this Wednesday when the boy is in day care, but the weather is cooling down enough for a couple hours fishing!!!

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## Barry_White

> Thanks guys, 
> Very glad I asked. The foam stuff would be too bulky in what I have chased out in the wall. I'll go to the shops and ask for some thinner stuff this week hopefully. 
> I was going to to it this Wednesday when the boy is in day care, but the weather is cooling down enough for a couple hours fishing!!!

  Like they say work is only for people that don't know how to fish.

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## bricks

Hey bloke wrap your pipe in normal grey duct tape, this will work well enough. The new copper pipes are thinner material ( cheap rubbish ) so it will corrode faster than old copper would have. Grey tape will do it, thats what i use, yes im a plumber, just make sure there are no holes in it ( do a good job)  
Lagging will not work as it is porous and will let moisture through. 
When you fill the chase up, try doin the corners on one day and then the next day when its hard you will find it a lot easier to bend the taps into a level position.

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## journeyman Mick

> ................Lagging will not work as it is porous and will let moisture through.........................

  What, the green plastic lagging that comes on the pipes? (Kemlag) I seriously doubt that. 
Mick

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## Barry_White

> What, the green plastic lagging that comes on the pipes? (Kemlag) I seriously doubt that. 
> Mick

  I agree with Mick. I have had Kemlag buried in soil for years and dug it up and the only area where moisture has got in is in the end where the Kemlag is cut and then it it has only gone in by capillary action a couple of inches. Kemlag is a closed cell foam so moisture doesn't penetrate. 
The chances of moisture getting in a pipe that has been rendered in is remote unless the pipe is leaking. 
The corrosion is started by the wet cement coming in contact with the copper and sets up a chemical reaction. 
Like you say bricks grey duct tape will do the job anyway.

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## bricks

Sorry Mick but eventually the kemlag will have to come off when it is heated or joined, and i was talking about the black foam insulation that someone suggested re smileys last post, plus you could put your kids through private school for the cost of kemlag.

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## journeyman Mick

Most of the jobs I've been on Kemlag has been used for all hot water and wherever pipes are chased into the blockwork. Combinations are usually covered in stripped off plastic lagging if it's around and any bare bits or joints etc are covered in duct tape. I reckon that by the time you factor in the labour component to wrap bare copper in tape then it's more expensive not to use kemlag. Wasting dollars to save cents, I reckon. 
Mick

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