How long will copper radiant tube last in concrete<

Bruce Good

I just looked at a house built in 1959 I believe, that is radiant heated and uses copper for distribution and for radiant tube. I have seen this in a few other houses, and fixed a few solder leaks in a ceiling with copper embedded in plaster. What is the prospective life of copper embedded in different materials?

John@Reliable

Copper in concrete

Bruce, In my service area we have alot of slab houses with this set-up and most are around this age or newer.I would say that a street with 25 houses on it , 13 systems that have failed already and the rest are living on borrowed time if you know what I mean!

Bruce Good

John, can you tell me the mode of failure? Is the tubing going from inside out or outside in?

hr

Depends on a number of things

generally the tube placed in radiant slabs is not completly encased in the pour. It's pretty hard to assure all the tubing is held up during the concrete placement, as you can imagine. If the tube is in contact with sub grade that could cause problems depending on the soil type, and moisture.

Over the years various products have been blended in concrete as fillers, some not so concrete friendly. Fly ash from coal burning power plants is a common filler. Of the 57 million metric ton of fly ash produced in the US, 17 million goes to the concrete industry. Virtually every batch plant uses fly ash, according to the redi mix associations. It's cheap, plentyiful and works!

Some experts claim the ash from plants that burn high sulfur content coal will cause problems with copper. News to me! I'm not sure how you would determine that, actually1

Of course the tube wall thickness, installation practice, movement of the slab, ground water, position of the moon, etc could all factor into the life for copper in the ground or in a slab.

Yet another concern is the PH and quality of the water INSIDE the tube excessively low ph will attack copper as will high ph.

Too many variables to give you an exact life expectency. If I were to consider copper in a slab, I might look into the recent coated varities to extend the life of the tube in unknown conditions.

I have seen type K copper get pinholes after less than two years in the ground in areas of Utah where homes were built on old mine tailing disposal sites. Kinda scary

My best guess would be 5-100 years for copper in a slab. Close enough

hot rod

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John@Reliable

Mode?

Customer gets out of bed to a wet floor mostly! Sorry couldn't resist. Have tried to fix some in pass,but sometimes "leak" would be 10 feet from where in shows up in floor. I don't try to fix anymore just install baseboard and no more leaks.I figure if one leak now more to follow.Outside in.