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Question

Hi guys,

Can any of u guys please settle an argument?

Copper pipework for new bathroom on ground floor, complete new build from ground up including bedroom on disabled grant.

pipework is bare copper under either concrete or between concrete and screeding, block insulation was put in and plastic membrane sheeting.

Now a guy yesterday told me those pipes should have been wrapped in some form of insulation etc, my bhuilder today told me that the pipes r not covered as the other guy was wrong.

The other guy said that there is something in concrete that can corode the copper in as little as 2 years.

Both the guy and my buider r decent guys, but whos telling the truth?

Cheers

Just to make things clearer.

The builders put the pipes under the concrete flooring with me agreeing that cosmetically it would look a hell of a lot better cos the route the pipes would have to take would be top of walls, I didnt fancy that, but the plumber did leave me a backup should a leak appear , he installed shut off valves to both pipes and has left enough room for working new pipewok, they made a small trap door on my laminate tile flooring. So god forbid I do get a leak then the insurance can sort it or I will get a local plumber to re-route the pipework.

Hey, u guys below r saying what about repairing leaks, ok but answer this, wat about underflooring heating?
I cannot remember if my pipes r buried in concrete or above and covered with screed, surely if its under screed and possibly somehow notches cut out to let block insulation cover and protect the pipes, I wasnt at home when the job was done, but the builder is a decent guy and did a lot more than he was paid 4.

Answer 1

I've seen many thousands of house concrete slabs with bare copper pipes sticking up out of the concrete. I have never heard of concrete corroding copper.
Setting pipes in the concrete slab is the universal standard used in construction of houses and commercial buildings with a concrete foundation. Pipes that come up out of a slab into an exterior wall should get insulation, but not in the concrete as the concrete insulates it. Anything set in the ground and concrete will not freeze unless you live on the permafrost.

Usually what happens is a pipe gets crimped while setting the forms or poring the concrete. Another cause is a slab that breaks and damages the pipe. If you have water coming into the house, you probably have a sweat joint that has come loose in the wall or a pipe that burst in the wall.

The proper way to resolve your question is to call the city building and planning department at city hall. Ask the building inspector what the code requirements are for residential plumbing in your city.

Thanks BT for making the distinction.
Now I realize what xenon was saying.
I said bare...OK...there IS the clear or bluish coating, but plastic coated is not thermal insulation as some have claimed. We are not talking about thermal insulation, we are talking thin clear plastic or other protective coating which is virtually invisible. Pipes are not required to be "thermally" insulated in the slab or under the slab unless you live on the Artic. They are not going to corrode or freeze and burst in the foundation for not having thermal insulation or conduit. I am aware that copper is corrosive when it is in constant contact with certain chemicals. In construction we always fasten copper with lead pins or solder. Iron fasteners will corrode it over time.
Yes, the pipes do have a clear protective coating.

Answer 2

I was recently on a job where the client had just had all the pipework replaced at a cost of £16000+ The reason was that when the conversion was done about 14 years ago, all the copper piping for heating, water and gas was buried, unprotected in a concrete floor. The acids etc in the concrete gradually ate through the copper. The gas pipe was the first to go, followed by the hot water a few weeks later. It's a well known fact that bare pipes should always be sleeved or run in ductwork. They WILL rot in time.

Answer 3

Hi - If copper pipe has to be buried in concrete then it should be 'plastic-coated'. This is a coating that is applied at the factory after the tube has been extruded. The plastic coating will protect against corrosion and also allows the pipes to expand and contract with temperature changes. Unprotected pipe WILL corrode chemically, and will also 'wear away' as it expands and contracts aginst the concrete/screed finish. I have ripped out systems installed in concrete floors without any protection and they have been like underfloor sprinkler systems. Unprotected copper pipe buried in concrete years ago was not much of a problem. This was because the wall-thickness of the pipe was much thicker than nowadays and so there was a lot more copper to corrode/wear away.
Ring your Building Control/Planning Office/Water Authority for current regulations. The last job of this type that I did, all the pipework had to be installed in ducts formed in the concrete floor and covered with a removable cover for maintenance. The regulations may have changed since then.

Answer 4

Drain your system from the drain valve near your boiler. When draining open all the bleeds on the radiators so air can suck in and the system can empty. Once it stops get a builders strong rubble bag and put it under the capped pipes and position so the water will drain into the bag. There will be a little pressure at first but don't worry it will soon slow when the cap is removed. If the capped pipes are a drop from upstairs you will only be emptying the legs and the water will soon stop. If there are a number of downstairs radiators connected to these pipes simply slide your hose over the pipe when the cap is removed then repeat the opening of bleeds. PS don't forget to shut the bleeds before you start to fill the system. Good luck. Just thought i would had it isn't unusual to find just the one drain point on a system near the boiler. I have used this technique of using a bag for many years especially on drops when changing radiator valves. I have found you can empty a full radiator in to a bag with no mess by holding the bag tight near the valve. This is also repeated by most of my colleagues gone are the days of emptying a radiator into a tub and then a bucket which is time consuming and messy. The self cutting taps are OK but we only tend to use them when changing a boiler with no drains on the system at all and to be honest sometimes you just end up squashing the pipe anyway so can be a waist of time.

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Answer 5

Generally, when building on a slab, all plumbing and electrical for that matter, are run in a plastic conduit. I don't know about corrosion, but any repairs that need to be done, would require demolition of the slab if not in conduit. When in doubt, call in the inspector. Your job was passed by an inspector right? Ask your builder for the paper work. Many builders try and avoid as many inspections as possible. Always avoid any builder that try and "get things by" the inspectors

Answer 6

I am a builder and in some of my extensions we have buried the heating pipes under the concrete.
Every time we have completly covered the pipes by either wrapping insulating tape all around it and then covering with duck tape or inserting in plastic pipe.
Copper will react with concrete breaking down the copper and also creating hollows in the concrete - Big Problems!

Answer 7

you have had a lot of answers to your question. and a lot of them have the right idea.
but concrete will corrode copper, not in two years but in fact quite a lot longer but they will corrode.
there is no reason copper pipes should not be buried under floor screed providing they are covered with denso tape. if we had every copper pipe installed above ground we would have a lot of ugly unneccassary pipework showing. if done properly during construction and following building regulations and using 100mm insulation under the floor screed you should never get a burst pipe. in which case no repairs should be neccassary. not in your life time anyway.. plastic pipework is far better under floor screed nowadays they can be screeded over with no protection. excepting gas pipes, they should still be run in copper. and covered with denso tape.

Answer 8

Gas Pipe In Screed

Answer 9

There is usually a way to get pipes where you want them without burying them, if they have to be buried, then they should be sleeved, you can buy sleeved pipe, or tracpipe if it is gas, but it is expensive, concrete IS corrosive to copper, read the instructions on a bag of cement and it will tell you, cement is alkaline, alkaline is as bad as acid, if you put wet cement on the under side of your arm, I give you 10 minutes before you have to wash it off. Ring Corgi (council for registered gas installers) they will tell you about burying gas pipes, ring the council and they will tell you (planning dept) they will tell you about burying water pipes. New build should probably have plans, ask to see them, the plans will probably not show these pipes buried.

Answer 10

Concrete should NEVER be poured over bare copper pipes,they should have been insulated in rubber or foam insulation, or better still should have been plastic pipes covered in insulation.
It WILL corrode in time , (8 years), and you will be flooded out.
In N, Ireland where I live the Housing Executive had to re-house an estate of people because the builder did just that..
The floors had to be dug out with pneumatic drills, the plumbing re-done, and the floors reinstated.
LATER
Poor ROMEO got it completely wrong, god bless him,and he calls himself a top contributor ?