Hydronic tubing -- copper revisited?

Carl_10

I'm getting ready to install hydronic tubing in my new house (currently under construction). The tubing will be in the basement (concrete slab on grade) and in the upper floor (concrete slab on steel bar joists). I don't want to engage in religous battles over tubing, but I need to select an appropriate tubing type.

I've read a lot on the topic. A lot of people claim that copper corrodes in concrete, but then there's http://www.radiantheat.net/tubing_main/ that suggests that type L soft copper is by far the best, with no degradation in a closed-loop system in low-sulfur concrete. I have somewhat of a preference for copper, since it's repairable, sturdy, readily-available, and since I've been working with it for decades. Also, it can take high temperatures without damage (e.g. accidental over-temp).

Does anybody have any compelling wisdom? Has anyone seen a closed-loop copper system in ordinary (non-Levittown) concrete degrade? Would anyone be willing to take a look at http://www.radiantheat.net/tubing_main/ and see if it makes sense?

Thanks to all...

--Carl

Paul Mitchell_2

In NJ

We have plenty of copper radiant. In my house there used to be some on the first floor. Mine developed a leak and I ran baseboard. Many other homes have it some 40+ years old. We did actually find a leak in one house..chipped up concrete and repaired. Good question....Does anyone really know what these differant Types of modern radiant tubing will do in the future?

hr

One concern

> We have plenty of copper radiant. In my house

> there used to be some on the first floor. Mine

> developed a leak and I ran baseboard. Many other

> homes have it some 40+ years old. We did actually

> find a leak in one house..chipped up concrete and

> repaired. Good question....Does anyone really

> know what these differant Types of modern radiant

> tubing will do in the future?





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hr

One concern

> We have plenty of copper radiant. In my house

> there used to be some on the first floor. Mine

> developed a leak and I ran baseboard. Many other

> homes have it some 40+ years old. We did actually

> find a leak in one house..chipped up concrete and

> repaired. Good question....Does anyone really

> know what these differant Types of modern radiant

> tubing will do in the future?





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hr

One concern

the SpanDeck commonly used over bar joists, for concrete pours, is usually galvanized coated. You would probably need to keep the copper from contacting this for potential electrolysis issues. Copper and zinc don't get along well, even dry

Soft copper generally comes in 100 foot coils so you will have a bunch of couplings in the pour, not a great idea.

If you are sold on copper look into EnviroTube or other plastic coated products, perhaps. You will lose some thermal transfer with the plastic layer, but much better than pin holes

All things being weighed, pex would be my hands down choice.

One challange I have run into with SpanDeck is the ability to conduct the heat from the slab downward, and also into the steel bar joist, if in fact you are planning on steel joists?

Be sure to think through how you will insulate the bottom of the steel decking, from the joist, or calculate the loss down to these.

Spray foam seems to be the only good option I have come up with to insulate the bottom of the steel decking. Hard to fit and fasten foam sheets or FG in those trusses.

Food for thought

I inherited a problematic steel deck/concrete pour radiant job. It was never insulated below and the upper rooms underheat and the basement rooms overheat. We did gain acess via some panels in the basement. With a temperature gun we proved the downward loss theory and heat transfer to the bar joists.

Think it through carefully.

As for concrete and copper in general.. it really depends on what your local redimix yards blend. Fly ash is common everywhere, blast furnace slag in some areas, ph of the gravel, etc. These all factor in to the sucessful marriage, and longevity, of copper and concrete

hot rod

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Weezbo

copper as distribution system in slab....

well, it certainly has been done ,and i went and read religiously word for word ,rather than a scant perusal... and having done so i cannot say i am convinced to leave pex a and go for the joy of copper installs....however if your so inclined then braze the fittings . pull the loops together under a flight of stairs ,or at the ends of dead headed corridors as that way the heat wont be like too good in any one part of an occupied space. the only disadvantage to copper is probably its resale value. The crooks these days seem to have become extremely enterprising and utilize skills they learn in jail as soon as they get out.

Carl PE

There sure are

a lot of Carls here..

I personally like the pex, but either system will probably serve you for decades.

One question, though. If you're going to bury some copper in a slab, wouldn't you want to spend the extra couple bucks and get type k?

Lurker_2

re

I grew up in a radiant heated home, copper in slab. In a neighborhood of hundreds of homes, we were almost the only one left after 17 years. All others had failed due to leaks in the slab. perhaps poor workmanship. perhaps pex is a better idea....

Larry Weingarten

Have you considered...

copper in the walls? Gypsum and copper don't fight. Picture nails and copper do if you don't plan accurately.;~)

Yours, Larry

tls_9

copper

My father put on an addition to house in the late sixties. He put copper in concrete radidiant radiant heat. Hard copper type "L", heated and bent around hardwood wheels. Swaged and brazed joints. He also put in a copper in croncrete sidewalk at the same time. both systems are still going strong.

With copper in concrete, its the concrete or the instillation thats the problem, not the copper.

Around here they now add flyash to the concrete which makes it a potential problem. just like in places years ago they used cinders. Both fly ash and cinders being byproducts of burning coal.

theres alot of copper in concrete systems still working going all the way back to the '50's. I could even show you a steel in concrete system from 1950 that is still working.

in my own opinion, copper makes the best job. Not being an expert on concrete, i would find it hard to recomend a copper / concrete system to anyone nowdays.

tom

hr

I've seen copper pinhole

in type K, buried in the ground, in less than a years time in some areas.

Granted it had to do with soil ph BUT..

Considering all the precautions and potential for problems why not stick with a proven plastic?

Couple with that the incrediable wide price fluctuation in copper prices. Just doesn't add up in my mind.

Do you know of anybody anywhere that actualy got warranty dollars for failed copper? I see lifetime warranty advertised for copper, but somehow ALL failures are not covered as they are related to outside forces??

I love copper for boiler piping, etc, works great for wires and pennies

Pex or composite pex seems to be the best for inslab applications, in my opinion.

hot rod

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tls_9

Yep...

Kinda what i was getting at when I said:

"i would find it hard to recomend a copper / concrete system to anyone nowdays. "



tom

Ken_8

I live in a Levittown

version of the LI-NY version in NJ and we have ~50 homes with copper in the slab. After 55 years none have corroded. Roughly half however have been abandoned from leaks. The leaks were caused by the complete absence of any rebar or "wire" and the slabs cracking from settling over that time and tree roots of 50+ year old trees torquing the slabs at the monolithic footings/slabs.

The cost of copper tubing however, despite its substantially superior thermal transfer rate, has lost some favor on an economic basis.

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jerry scharf_2

I'm a platic boy

But I have a guy who I respect alot who uses copper whenever possible. He charges the piping with helium to 300PSI and it there are any drops, he knows there is a leak. Then ho goes around and shiffs it out. He leaves ot this way while the evil flooring people do their work. He also has a $200 per hole fee he hits the flooring people for. The crews know it will come out of their pocket, and with the helium you can locate and prove the failure in 15 minutes. He has very few problems.

He can't do this with PEX (heliem leaks right through the tubing,) so he prefers copper. I never asked him whether the copper is coated, I'll ask next time.

thought people would enjoy this.

jerry

Carl_10

Thanks!

Thanks to everyone for your suggestions. I suppose I'll go with Pex/Al/Pex for tubing in the slab -- time to learn something new!

--Carl