Mark wrote:All I am struggling with at the moment is the PEX tubing that will end up encased in concrete. Everyone (the concrete fellows we got quotes from, our plumber neighbour, etc.) tells us that this is a piece of cake, but I really don't want to screw this up as repairing it will be incredibly expensive. So I'm looking to avoid any gotchas.
Karen Walk wrote:I see that you are located in VT (as am I) - how do you protect foundations and floors from frost in this climate? I'm genuinely curious.
Karen Walk wrote:Regarding mice or rats getting to radiant tubing embedded in concrete - I find this really hard to believe - have you ever seen it happen?
Karen Walk wrote:I have seen a hole in radiant tubing embedded in concrete fixed within a few hours. The concrete needs to be chipped out around the leak, the tubing repaired (usually a coupling) and then new concrete filled in. It's not ideal, but is very rare.
Aquatherm wrote:Thus it can be shown that sand is a good replacement for fiberglass pipe insulation in underground, direct buried applications. It's easier to install and costs less.
Karen Walk wrote:Radiant tubing beneath an earthen floor would be pretty cool - but an earthen floor is functionally different than concrete.
I am facing the same questions here about colder climate flooring design. As a Permaculture forum, we should be building any structure firstly to have low energy input materials, the longest lifespan materials, avoiding any chemical inputs and residue & avoid plastics where possible.
Jay - if you were designing this floor system for a client, would you use a layer of sand between rock base and an earthen floor on top? How thick would the layer of sand and earthen floor measure?
Or would you use pex tubing in a bed of sand under a wooden floor?
Ashley Reyson wrote:This is a lovely discussion!
Karen, thanks for extending my list of gotchas and suggestions with a few that didn't occur to me to mention. I agree, especially about it being a three person job! The challenge of offering such suggestions is that once you learn to do a thing it's easy to become unconscious of where the potential challenges are.
Jay, I don't feel unduly poked by your comments. As I said, the home I built 20 years ago wasn't nearly as unconventional as I'd build today... and most of the changes relate to my desire to try more natural methods and materials. If I'm ready for the next building project in a couple years as I plan, I'll probably chat with you further about integrating wonderful things like hydronic heating (and cooling) with traditional techniques.
Now, I'm going to expand the topic away from materials and techniques, to how we actually help the OP. In doing so, I'm going to reference the Wheaton Eco Scale.
Mark came here looking for confidence and tips on his first hydronic install. He indicated that he has a plan ready to go and approved by the local department of making you do things their way. He has some DIY experience, but is neither a full time builder nor a natural building expert. It sounds like he's surfing the edge between rapid learning and overwhelm... not necessarily looking for a pile of additional things to learn ASAP unless they're essential. If I were Mark in this situation, I'd probably be looking for help with my specific question rather than looking for recommendations to scrap the design. (And I'm not Mark, so I might be totally off.)
So how do we help Mark?
Help is only help if it's within someone's ability to receive it. I suspect, Jay, that you're a couple notches ahead of me on the Wheaton Eco Scale with respect to natural building. That means I think I can learn tons from you and would love to hang out and pick your brain. I suspect that you're quite a few notches ahead of Mark, which Paul suggests guarantees he'll see you as insane. Hey, great minds suffer than challenge often.
Then again, perhaps Mark is right there with you Jay. Perhaps you just saved him from implementing a design he'll regret, and gave him confidence to take a step farther ahead even though he's already pushing the limits of his local building community. It takes courage to be first to do something strange in your locale, especially when your funding it with a house sized budget.
So how do we help Mark? We invite Mark to tell us how far he wants to push the envelope, then we answer within his ability to use the information.
Go ahead Mark, tell us how we can help. Jay has far more knowledge of natural building than I do and more important, he actually has experience with it. If you want to go there, he's a far better source than me.
Until Mark replies with clarity on whether we're pushing his limits on the Wheaton Eco Scale, I suspect that our disagreements about the rest of the issues would be better served in another thread or two. A couple subjects come to mind: a) "In-mass hydronic heating with natural building techniques", b) "Modern and Natural Solutions to Ecological Problems of Concrete". I don't know that I have tons to contribute to those threads, but I'd love to read them and I'll sure bring questions!
Best regards, and thanks for bringing your passion!
Mark Fox wrote:This seems about as close a forum to ask my question as any. Apologies if there is a better place.
The very quick back-story is that we have had the architectural and engineering on a off-grid home done for several years, the land is bought and paid for, and we have finally begun to make real progress on the building process. In order to keep costs down, I am doing much of the work myself. I enjoy DIY work, but am struggling with all of the skills necessary to build a far-from-conventional house. This week, and probably next, I'm getting everything ready for the concrete. We have a simple 6" thick slab that sits on top of 6" of styrofoam. The slab has PEX tubing runnng through it. Hot water is pumped through the tubing to heat the slab. The water is heated by a solar hot water system. The system is intended only to keep the house above freezing if we are ever away during the heating system. While we are home, the system will provide for some of our hot water needs and a masonry wood stove (or two) will be used to keep the household comfortable and heat water.
All I am struggling with at the moment is the PEX tubing that will end up encased in concrete. Everyone (the concrete fellows we got quotes from, our plumber neighbour, etc.) tells us that this is a piece of cake, but I really don't want to screw this up as repairing it will be incredibly expensive. So I'm looking to avoid any gotchas. For example, I just learned that I will need to use PEX tubing with an oxygen barrier. Our runs are 200 to 300 feet long. Rather than buy 100-foot lengths of tubing and connect them, I'm going to buy a single 1000-foot roll. Also, our plans call for 3/4" tubing, which seems really excessive, but is what the engineer asked for, so I guess I'm stuck with it.
Any advice from someone with a bit of experience would be very valuable to us.
Terry Ruth wrote:I'm a little confused you say you have had the engineering done for several years but you are soliciting for arguments against it or to validate it? Please post the Engineering for the HR system so I can review the analysis? There are CFD models that should have been created, or hand calculations? Then I would have spec'ed out every detail that you should not deviate from. Can you post the HR drawing too, to fully understand the entire system we need to know the wall and roof structure as well. You just cannot put a slab configuration out here and expect to get the proper advice on heat transfers/capacities, etc, especially. I think Jay gave you sound chemical advice you take or leave. There is no isolating, the dynamics in a home are many and act as a system....really no different than other dynamic structures (aircraft, auto, watercraft, etc....)
Ann Torrence wrote:Mark,
Our neighbors did exactly what you propose, mostly with their own four hands. Solar radiant floors, masonry heater from a kit. They also did a rammed earth floor in part of the house, straw bale walls and lived to tell about it. Now they've moved in and are thrilled with their home. Especially its minimal energy costs.
You said one or two masonry heaters - is the plan for the floor reinforced in those areas?
I hope you will start a project thread about your building process.
Mark Fox wrote:I've been wondering whether I should post my progress somewhere. Honestly, I didn't think Permies was the right place. But maybe I'm wrong.
Karen Walk wrote:
For your outdoor boiler - what are you using? Are you using a system that has a hot water tank for thermal storage? I have a Garn at my house - and it works great. 1800 gallons of water storage. Tarm boilers can also be provided with a thermal storage tank. If it's sunny in the winter, we can let our Tarm coast for a few days. When it's cloudy, we fire every day.
Karen Walk wrote:
Also, for Mark's slab - are you suggesting installing temperature sensor in the slab so that he has the option to control the radiant based on slab temperature? I think that's what you meant...
Tim Malacarne wrote:I sure wish I'd of known about the oxygen barrier pex being so important, it's too late for me! Have a cast iron radiator for a heat absorber, and black iron pipe manifolds. How badly am I hosed? Is there anything I can do to combat the corrosion?
Thanks, I hope you don't mind my interjection....
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