Run Radiant pex straight across thickened slab
Hey all,
I have a slab on grade we are building with radiant heat pex. Some of the zones traverse a portion of the slab that is thickened to support load bearing walls.
The pex is embedded in the dimples of the insulation — under the slab. The pex is pretty stiff, even when left in the sun. In preparing to install the pex, I am wondering if it would be okay to run straight across the thickened part of the slab to get to the other side — without dropping down and then back up with the insulation.
Thoughts….?
P.S. In a previous question, I did ask about doing something similar with the radon pipe and the consensus was that in that situation it was perfectly fine. Does same apply to radiant pex tubing?
Thanks all!
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Replies
As with your other pipes I would wrap it with a couple wraps of foam pipe wrap to give it a little cushion.
https://www.supplyhouse.com/Oatey-38712-4-x-82-Foam-Closet-Wrap?utm_source=google_ad&utm_medium=pmax&utm_campaign=pmax_nca_test&gad_source=1&gclid=EAIaIQobChMIquL3_LychgMV_CGtBh3n2wauEAQYBCABEgLnhvD_BwE
I'm a bit confused about the foam wrap on the Pex. Aren't the PEX pipes expected to be in direct contact with the concrete anyway. For example, when attached to rebar in the slab, I haven't seen, or read anywhere, of wrapping them. What function would the wrap be performing in this case?
Thanks.
You are transitioning between two different substrates that will not necessarily act monolithically. If it was all embedded in slab it would all move monolithically. But your set up has the possibility that the sub slab insulation/ ground moves in relation to your concrete, which could shear your pex. Think about an earthquake, even a minor one. That is why you always try to create a void space/ cushion where pipes enter/ exit concrete. You should also do this where they exit the slab to your manifold, and at your other plumbing locations into walls.
Got it. Certainly wont hurt to put that wrap on.
Thx