Charlie:
Frank writes to us from Waukegan, Illinois. He says, “We have some copper piping in for a slab for our hot water system. A company put it in after the old pipes burst and to fix it they just added copper in the bad areas. Now we have got to put concrete back on them. Concrete and copper, you have said it is a bad combination, right? What do they do to protect the copper pipes?
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Tom:
Since this is a floor heating system, I am not sure what kind of system they have. Most of the systems I have seen have either been coated piping or we have electrical grids we put in the slabs to. If they are covering with a slab and it was always done this way, you are just going to have to cover it with a slab. You are not going to put a coating on there since it is a heating system.
Charlie
Okay.
Tom:
Whatever the manufacturer of this heating system recommends and whatever it is supposed to be done, then that is the way you do it. I don’t have enough information Well, it is a heating system. If it was just a water system, then we would wrap them when they penetrate slabs because of the expansion and contraction and dissimilar metals. It will start to rot the copper pipe because of the limes and sometimes you have iron and concrete from the aggregate. It will have iron in it.
Charlie
The Portland itself?
Tom:
Not the Portland, the aggregate, which is the little rocks they use. You can get some with iron content in there and that is why you get a little rusting sometimes and you have the steel in the slabs too. You just have that dissimilar metal problem where it will react to the pipe in a bad way.
Charlie
I am surprised there is not a coating of some kind you can put on those pipes.
Tom:
The one that I have seen used, when I as living up in Lake Placid, New York. Very popular, great heating system. They were all coated, but they were special pipes for radiant heat systems in floors. They could be used in wood or in concrete, where you would cover it up because you had second floors and basements and things like that so they were used all over the place. I have never just seen plain copper in a slab so I am questioning what that heating system … Who put it together for him.