I am putting in an earth contact home. I have picked out all the sinks, toilets, tubs, showers, etc. I am confident with the measurements, because I made the floor plans. But I am concerned about problems in the future. Should I put every thing in a sleeve so it can be easily pulled out later if need be? How would this work with the cpvc pipes turn under the slab? Any worries, I have not mentioned that I should look into.
Thanks

I am putting in an earth contact home. I have picked out all the sinks, toilets, tubs, showers, etc. I am confident with the measurements, because I made the floor plans. But I am concerned about problems in the future. Should I put every thing in a sleeve so it can be easily pulled out later if need be? How would this work with the cpvc pipes turn under the slab? Any worries, I have not mentioned that I should look into.
Thanks
I have no idea if that's best practice, or code-compliant (I'm not a plumber) but it sure makes sense to me, especially if you plumb with flexible PEX.

It seems to me that having Sch 40 PVC (3" or 4"?) conduits/sleeves/etc which the flex was run through, and could be replaced if needed, would be cool. Note, however, that if there's leak inside the conduit, the water will come out of the lowest point, once the conduit fills up. You could maybe take that into account and make sure the conduit either drains, or the lowest opening is a place where it's (relatively) convenient to have a water leak.

For the drainage, I'm not sure sleeves would work.. if it were me, I'd probably use Sch80 PVC, or maybe cast iron.

I am putting in an earth contact home. I have picked out all the sinks, toilets, tubs, showers, etc. I am confident with the measurements, because I made the floor plans. But I am concerned about problems in the future. Should I put every thing in a sleeve so it can be easily pulled out later if need be? How would this work with the cpvc pipes turn under the slab? Any worries, I have not mentioned that I should look into.
Thanks

Frankly, I wouldn't put CPVC under a slab, sleeved or otherwise.

If I were you, I would run the water piping for each fixture under the slab in PEX as a individual home run, and then combine them into a manifold above ground.

Not having any fittings below the slab would negate the need to sleeve the piping altogether.

I *would* recommend insulating the piping with 1/2" wall foam pipe insulation, though, to protect it from being damaged by your backfill.

The foam insulation Grower's referring to is called ArmoFlex. We do not allow ANY joints in our water under our slabs. Good luck, Tom

The foam insulation Grower's referring to is called ArmoFlex. We do not allow ANY joints in our water under our slabs. Good luck, Tom


They're allowed here in both plastic and copper, but copper joints must be brazed with a silver bearing rod.

But being allowed doesn't mean I'd recommend it.

I'm still partial to the home run/manifold system myself.

To me, the home-run/manifold does seem like the best idea, and it's more or less what I was trying to articulate before.

For the minor cost of materials, would the original poster's idea of using PVC pipe as a "conduit" be worth the trouble?

Certainly it would provide the protection against the backfill, and I would think that two (hot/cold) PEX lines could be run in one 1.5" tube. This wouldn't provide a lot of thermal insulation, but then again PEX is pretty good at that on it's own, isn't it? And being inside the PVC would probably also provide quite a bit of heat-retention for the hot water too...


So, if this was done with 1.5" PVC, using 45deg fittings (never 90), and still no joints in the pressurized pipe (PEX) under the slab, wouldn't that be the ultimate setup?

This isn't exactly an idle question for me, as I'll want to run some plumbing in my garage. (planning stages)

~aaron



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Certainly it would provide the protection against the backfill, and i would think that two (hot/cold) PEX lines could be run in one 1.5" tube. This wouldn't provide a lot of thermal insulation, but then again PEX is pretty good at that on it's own, isn't it? And being inside the PVC would probably also provide quite a bit of heat-retention for the hot water too...


Well, there isn't supposed to be any heat transfer with PEX tubing, which is why you're allowed to have hot and cold piping share the same hole in framing members, but I wouldn't recommend enclosing them together inside of a conduit.

The claims of heat transference not being an issue seem somewhat contradictory when you consider that PEX tubing is also used in hydronic in-floor radiant heat systems, where the high degree of heat transfer is a selling point.

The claims of heat transference not being an issue seem somewhat contradictory when you consider that PEX tubing is also used in hydronic in-floor radiant heat systems, where the high degree of heat transfer is a selling point.


Well, that makes sense. So the cold water would get hotter, and the hot water colder, if they ran at the same time. But no overall heat/energy is really lost, so the ultimate temp at the faucet should be (about) the same...

Having to run parallel 1" PVC seems like a lot, depending on how much you have to pay for it.

Is there a difference in the thickness with the hydronic PEX versus the water supply?

Related, is it allowed to embed the hydronic PEX right into a concrete slab or floor? That would make me think that there's no real issue with backfill/damage for PEX.

I used to own a house which had copper embedded in the slab for heat. (1950's tract house) Mine was the ONLY house in the neighborhood which still had a working in-slab system, all the others had developed leaks (or froze during power outages) over the years... rumour was that it was due to the luck of the draw, and ending up with a piece of gravel/aggregate touching a pipe, and heat/cold expansion cycles would eventually wear a hole in the copper.

~aaron


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Well, that makes sense. So the cold water would get hotter, and the hot water colder, if they ran at the same time. But no overall heat/energy is really lost, so the ultimate temp at the faucet should be (about) the same...

In my opinion the cold water would get hotter.

Butt, you know what they say about opinions and a certain orifice.



Having to run parallel 1" PVC seems like a lot, depending on how much you have to pay for it.

It would add to the cost, but remember I'm not advocating you sleeve the piping.

Sounds like overkill to me, really, the only time I have ever sleeved PEX tubing was when the 1-1/4" water line I was installing was viewed by the forward thinking homeowner to be sufficient for the current home, but insufficient for an addition to the home he planned for the future.


Is there a difference in the thickness with the hydronic PEX versus the water supply?

Well, there must be some difference because the tubing is use specific.



Related, is it allowed to embed the hydronic PEX right into a concrete slab or floor? That would make me think that there's no real issue with backfill/damage for PEX.

Protection from backfill damage isn't required, it's just added insurance -- A means of covering my own butt, really.

Although there is the high pressure/low pressure factor to consider, piping under high pressure is more likely to move (and rub against debris in the backfill), as in a potable water system, than a low pressure hydronic system.

Again, I'm all about covering my butt.