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I’m building a house and have been planning to use Stadler Climate Panels or equiv. Didn’t want to deal with staple up issues or gypcrete. Problem is that those panels go for something like $5 a square foot, which really adds up. On materials, you can get aluminum sheets for ~$1sqft combined with 1/2″ plywood cut into strips, and that would save $10,000. Not counting my labor of course.
What are the issues with making your own? That is, covering entire floor with Al and then laying down the pipe and the plywood sleepers. I would probably go ahead and butt the plywood quite close to the pex to reproduce the panel design. The systems generally have fairly tight snap-in fit so I presume that they hold the pipe down against the Al for heat transfer. Are there shallow staple like things to hold pipe down to Al sheets but still only be 1/2″ high? You could also simply bevel the plywood strips as you run them through a tablesaw and butt them to the pipe as a hold down and increase thermal contact. I suppose you could also get really fancy and cut and bend the Al sheets into -u- (like you would make for staple-up supports). That would improve thermal transfer and actually bring the AL up to the top of the plywood instead underneath.
What gauge of Al would be recommended? Why wouldn’t this work as well?
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If DYI, where you tend to discount your own labor, then is cheaper to roll your own; in production mode I'm not as sure. But I think you need the aluminum *above* the sleepers, bent into a U under the tubing. The aluminum used for this is softer (like lead flashing in consistency) so easy to shape.
The attached picture shows 7/8" tubing with 1.5" sleepers, but same idea. The 1/2" tubing is 1/2" ID so about 5/8" OD so need 3/4" sleepers. Borrowed from http://www.radiantcompany.com/details/suspended.shtml
Another choice may be to make yourself a sand box between the sleepers at even less cost. I was just (just!) starting to do so myself, but am now reading up on other views in the "Using Sand as a thermal Mass" thread.
*OK, try 2 for the picture attachment (where's a computer guy when I need one?)
*I'd put the aluminum above the tubing with the tubing between plywood such that that tubing projects just a hair higher than the plywood. So it pressed firmly to the aluminum. Making a U-channel would be a nice touch and I can imagine a jig: A hinged plywood sandwhich with one side being routed out and the other side having a length of iron pipe a touch smaller in OD than the PEX. Then toss in some aluminum and drive over it in your 7,200 pound Ford Excursion. But I wouldn't do that. Too make time and bother. Spend a few hundred on a thicker gauge of aluminum and save your labor for other efforts.Regarding thickness of the aluminum: Aluminum is 160 to 230 times more conductive (per cross sectional area) than concrete. So 0.01" of aluminum can spread as much heat, as evenly as 2" of concrete. Not that 2" of concrete is the end all for RFH, but to equal a gypcrete floor, you don't need much aluminum. Thicker aluminum would always be better - more even heat and slightly lower water temperatures to acheive the same BTU/square foot. Get some samples and play around with it. You need to be able to cut it easily on site and shoot a nail or screw through for the flooring above. What are you planning to cover it with? -David
*One gent I know has his kids make the plates for him. With the correct aluminum (not the rolls of flashing Al found at the home improvement stores) they're quite easy to make, as the correct aluminum is quite malleable.David described a functioning jig which is similar to what he uses...a baseplate with a half-round routed out of it, and a hinged pipe to force the Al into the jig. With the pipe down, the flanges are folded over.His kids are elementary school age and it takes them about 15 seconds to form each piece.I believe Radiantec, which is prbably the most DIY-friendly RFH company out there, sells flat stock. I thought they even had plans for the jig, either on-line or by request.Do be careful jury-rigging Al plates on your own...if you're going to try, use the proper metal stock and be careful how you fasten the plates to minimize metal expansion/contraction noises.
*I did a job with aluminum flashing. No noises. and the home is heated fully... so I guess it's not that perfect a science.near the stream not wanting to pay way more than flashing for easy bending,aj
*Thanks guys.There will be mostly solid hardwood floors, so I'll want to see the pipes. Yes, RadianTec sells 8" x 16" malleable al for the staple up approach. Something like $1.30 per sq foot. I have the brochure where they describe bending it completely around a pipe and then splitting it back open again. So how bad would expansion/contraction actually be? The control system will be one of those gradually ramping up/down of water temp based upon temp movements in rooms. The water circulates continuously, and so there should be few if any large shocks during normal operation. Only when turning it completely on/off.
*Aj,It wasn't clear from your message-- you didn't bend the flashing, just installed flat?Gotta go check out what decent thickness flashing goes for...
*Marc... I did just as Radiantec said to... I just bought the stock alu flashing... bend it around smaller diameter pipe as it will spring back a lot. It didn't fit too tight, but then i banged it tighter as I installed it.near the stream,aj
*My latest idea is to play with aluminum foil to make my own Warmboard.near the stream,aj
*Could you use aluminum trim coil? it bends easy nuf
*Any aluminum could work... because no aluminum actually works. Less btus that's all...I would think flashing costs less though.near the stream,aj
*Jim, I want to use sand as my thermal mass also.....where did you get the thread "Using Sand as a thermal Mass" ?
*Ray, very same place this thread is. Just scroll down the list a bit.b : )