radiant tube in concrete repair help

funghi2

Hi all, im doing a ground up building and we are doing radiant floors throughout running off a navien combi boiler. we are doing a poured concrete structure, burying the tube in the initial pour. as luck would have it, a section was broken by heavy handed concrete workers. it was under pressure and we saw where it broke. the GC cut the pipe at that section then spliced it together with a union fitting and crimps clamps. they finished the pour without incident but somethign didnt feel right. I asked the plumber he said it will be fine but he wished the gc put a sleeve over the repaired piece, but he said it will be fine either way. but im thinking concrete is corrosive and thats never good in contact with the fittings or clamp metals. I called the pex manufacturer and they gave me a default "we never recommend splicing and embedding in concrete". WOuld love to hear your opinions on this as im shting a brick here. In the meantime ive marked the locations on blueprints in case there any issue with it in the future. SHould i let sleeping dogs lie, or should i take more drastic measures to fix?

Ironman

It should have been wrapped or sleeved.

Depending upon the amount of fly ash, concrete can be very corrosive.

hot_rod

All the pex manufacturers have a procedure for a splice like that, if you want to maintain their warranty.

Not sure why it would need a union? Another potential leak.

Typically a coupling with a special sleeve or tape that doesn't react with the O2 barrier is what the factory wants.

If it is a reputable Pex brand, look up their procedure online, send it to the GC and building owner so you have it documanted.

Zman

What type of pex and "union"?

funghi2

the workers busted a section of the pex while pouring the slab, that why he had to repair on the fly. so they spliced in another section of pex using pinch clamps and 1/2" PEX x 1/2" PEX Brass Coupling, but they did not sleeve or wrap the repair before putting the pex under the concrete. i contacted hose manu and they said they never want a connection embedded in concrete even if sleeved or wrapped which is what id expect them to say. now concrete has cured. do i have they chip up the repair areas to sleeve or do you think it will be "ok"? my gc said this is a problem that would take decades to leak, but ive noticed him taking all sorts of shortcuts

funghi2

orange barrier pex and 1/2" straight brass coupling

hot_rod

Hard for anyone to predict how long it will last. Copper and brass have been in and thru concrete for years. Stainless chinch rings?


Any floor covering going over the slab?
While not ideal, would you rather see a patch in the concrete?
Or demo the entire slab? New tube, mesh and concrete? Would a insurance claim cover it?

If it stays dry in the concrete it has a better chance of lasting “decades”

funghi2

wood floor going over the concrete. so a patch wouldnt be unslightly, more its the cost and labor of chipping it out, possibly causing further damage.

demo'ing the slab would not be covered and the cost would be way too much


hmm not sure on the clamps, ill check one, thought they were mostly all stainless.


i guess what im really asking, and it may be impossible for you guys to say, is this going to corrode to a point of leak inside of 5 years or so?? is it more efficient at this point to chip up the spot and provide a sleeve or wait for a leak years down the road and do it then?

hot_rod

Are you a gambling man?

If you mapped the splice, I’d have the installer saw an access and correct it to the manufacturers requirement. Some suggest the splice be in the ground below the pour.

Rehau has a shrink wrap, I think Viega has a special tape wrap, google around for the various manufacturers recommended method

This is not a new or unusual situation, tube,wire, conduits are spliced all the time.

Watts Radiant used to sell spliced radiant hose at discounted price, a shrink wrap Splice as I recall.

If replacing the entire loop is not an option, you have two choices, roll the dice or chop and perform a better splice.

hot_rod

If it happens to be an A pex, expansion with a composite coupling instead of brass would be the best splice. I believe the expansion method is by far the strongest pex connection.

Linerless 3M tape, 50% overwrap is Rehau's suggestion, especially with brass fittings.

Scotch® 130C is an example of linerless splicing tape..

funghi2

let me check who makes the pipe. very detailed answer , thank you for that. i am a gambling man


and i consistently lose in casinos.

hot_rod

I get the impression that a questionable splice in your system may keep you up at night?

If so, there is no better time than now to make it right, if it is going to be floored over.

How accurately did you map it? Pics and triangulate the location is the best way to find it within inches.

It's not a huge deal to chop some concrete, the sooner the better, it will only get harder as it cures.

Saw cuts make for a nice patch.

funghi2

ok one last q, the plumber said he would usually put a sleeve over it and duct tape it. is duct tape safe for the pex tube??

hot_rod

Lesson learned, why not do it the way the manufacturers tell you?
Why add insult to injury?

Rehau states linerless tape only, Viega sells 15320 repair coupling tape, @ 20 bucks online. Some pex brands offer a heat shrink covering.

I've heard the adhesives in duct tape and regular electrical are not kind to the pex?

funghi2

agreed, he should do it the right way