radiant wall details?

archibald tuttle

sorry to make a new thread on what would seem like virtually a sticky here, but my forum search keeps finding various folks who posted links to pictures and diagrams of radiant wall system ideas but they are all behind some error firewall in the old 'wall'. Also there are a number of threads that say they are including or linking to such info elsewhere on the web but they don't have any links or attachments that I can see.



So if anybody would be willing to do this again (or maybe explain if I have some kind of browser problem that prevents me from going to the archived threads or . . . ) that would be much appreciated.



I'm dealing with how to accomplish low cost retrofit. Which doesn't mean I'm unwilling to spend money, but I've been emperically engineering radiant at levels I could afford since before there was an internet, and while I think that a lot of the high end install materials are clever solutions, they usually exceed the budget that I can afford for projects.



So the kind of thing I'm wondering about is maybe foil faced foam on the wall 1 or 2" thick and firring strips the thickness of which is calibrated to sandwich 3/8" pex tubing probably secured with the single screw clips that are very thin plastic and loop all the way around the tube and back on themselves (no idea what the heck we call this clips, I'm always asking for them at various wholesalers and they want to get out the thick plastic one nail clips which is not what I'm talking about) between the foam and the wallboard, or possibly hardibacker and tile up to the chair rail level.



The lack of full insertion of the pex into a dented foil relief as in many of the manufactured systems for floors (and I assume walls) is sure to slow the transfer from the pipe to the aluminum surface on the insulation, but I figured at least this surface would spread the pipe heat across it's surface and radiate it towards the back of the sheetrock or hardibacker. Now, this could be compensated for by using sheet aluminum foil formed over the pipes and adhered to the foil faced insulation with say a light coat of spray adhesive. Or maybe just by adding more pipe, so you have less circumference in contact with the foil face but of more pipe runs.



Assuming I'm getting reasonable conduction transfer to the foil face, then the transfer to the sheetrock (other than a bit by conduction from the other side of the pipe) would be a radiant transfer, so, I'm thinking it won't be much more frustrated by the 1/2" air gap than by the more miniscule gap between the pipe depression medias which are still separate from the finish floor or wall and would have some minor air gap over most of their surface area.



Glad to become better informed on radiant physics if this impression is a misconception.



A plumber friend of mine whose always playing with ideas in this area suggested just making a concrete chair rail, maybe a couple inches of foam, put up the pex with the click clips and then make a form 2 or 2.5 inches inside foam and pour maybe eagle floor mix with fibers in there (a high compressive strength mix with limited small aggregate). This could be a tile base or you could adhere some kind of thin high density finish product or even thing hardwood or maybe tint the stuff and use a textured form of some sort and let the concrete be the finish. So depending on the baseboard and insulation details you don't loose that much more than with baseboard and you get a little shelf around the room -- great for packrats like me.



The kitchen doens't work out too well but maybe you can use stone countertops (often my splurge) over radiant tube by vaiours details which could be discussed elsewhere (or here).



Or detail 3 , always having been a fan of fuller plaster systems, what about using expanded metal mounted with say a 1/4" standoff from the insulation with pex clipped to it and then full plastering the whole thing with either a gypsum or gypsum cement amalgam. Don't know if anything like this could really survive as a finish surface given thermal stress - except that distressed finishes are all the rage. But maybe as a tile base or to be parged over with another finish maybe once its set and had the heat put to it a bit. . .



Figure maybe somebody's been down these ratholes, so thought I'd ask before I climb in. As per usual, I have a job I'm thinking about and I can always just install baseboard and put this research on the shelf for future projects. But I've got a week or 2 to stop and consider these possibilities before proceeding.



Also, seem to remember that somebody here was experimenting with some miracle graphite film product that might have been self adhesive or . . . but it was in early testing last couple years. What ever happened with that stuff.



Thanks,



Brian



PS -couple questions about the new (or new to me) Wall which, as is usually the case with us conservatives, I liked the old one better. I'm not just talking it out on the proprietors here, same is true for my favorite legal blog Volokh.com that migrated to a new platform.



What is the point of signing in if you still have to do that stupid anti-spam thing? There is a J in there now and I can't tell if it's upper case or lower case. I'm glad to join, get e-mail from the board or anybody on the board, I don't care, but I can't stand all this stuff you have to go through just to avoid a couple unsolocited invitations to see eastern european women in various states of undress -- doesn't seem worth it to me.



Also, I never got to choose a clever handle. How do some people have sweet names and everybody else is just themselves. I'm glad for people to know who I am, but my avatars are usually prosaic rather than pictoral. Maybe this is something I can change in My Account . . .

Mark Eatherton

You are a man of few words....

NOT :-) Me either.



Re: Radiant Walls, I have done it many times, including my own. Use heat transmission plates if you want it to be efficient with low temperature water.



If run of tube is to be at right angle to studs, use sleepers to off set tube from the face of the studs. Alternatively, route a groove into the face of the studs and skip the firring studs. Works fine on non load bearing walls.



Some of the older walls I have worked on were the metal lathe and plaster walls that you described. They work well, but require higher operating temperatures.



Have also seen vertical plates, parallel to the studs, but run from floor to ceiling with edge of plates nailed into the stud. Not certain how easy that one would be to finish.



Have not seen the graphite used to do walls yet, but sounds like an interesting concept.



If you can keep your heat transfer in the conductive mode, you will be light years ahead, as opposed to depending upon the other two modes.



Regarding the changes to the wall, Dan spent a lot of time and money putting it together to avoid the iBOTS that were attacking the web site. Kind of a PITA, but worth it to avoid them crashing the party.



All letters are CAPS, the letter O is never used (number zero is used).



Here are some pictures of the most recent radiant wall I didi on my own home in the mountains.



Welcome to the new Wall.



ME



I insulated with fiber glass insulation behind the radiant wall prior to putting the plates in .

archibald tuttle

good nature

Mark,



it would be untoward for me to award myself the appellation of 'good natured', but you are without doubt the best amassador the wall has. Both the content and character of your responses improve the spirit of this lively juke joint.



So, inquiring minds want to know, did you make those aluminum pans.  They look much wider than the available stuff I've seen. Are they 3' long per section and are they 12" wide (less the dent).



I've been working on a die for my hydraulic press to make 30" long pieces.  I thought I had it nailed, but my initial press came up a little short. I used a 7/16" rod welded to a 3x3 steel tube strongback.  When I used the same rod in a wood routed form and beat it in with a hammer it worked perfectly, but in the press, my channel came up shallow.



I guess I've got to make another one with maybe a 3/8 x 3/8 square welded on first and then weld the 7/16" dowel to that.



Anyway, interested in your sourcing.



That does look like a nice detail, although my intuition is that I'd like to put a sheet of foam behind it as well and then put the firring.



I kind of like the horizontal distribution. Assume that the feed is at the bottom and the return off the top, but tell my imagination is too vivid on this point.



All in all, is this just added comfort with warm floor or are radiant walls more effective at reaching people - given as I expect that sheetrock is a better transmitter than most flooring choices. It seems like your total pipe runs are much less than I would have considered necessary. How many walls in the room are you hitting?  Is it equally effective from indoor walls or . . .?



Thanks,



Brian



PS -too bad about the spam bots but thanks for the tip on the letters.  That was biggest problem is figuring out whether they were capital or not.

Mark Eatherton

Uponor heat transmission plates...

Those are some old Wirsbo heat transmission plates that one of my wholesalers still had laying about. They are 2' long and were intended to be installed between floor joists, 16" o.c.



The walls are actually augmenting my radiant windows in the same room. The radiant windows are for the most part the primary heat source in this room.



I have no radiant floors in this home. I wanted to prove that radiant COMFORT can be delivered without the use of radiant floors. I have radiant ceilings in the balance of the home, and they work excellent, and the floors typically run about 72 to 75 degrees F, so I can walk around in socking feet, no problem.



The ceilings are made by Roth, and could very well be used for radiant walls (aluminum plates on high density styrofoam), but are fairly expensive, but an excellent heat transfer agent. They operate similar to WarmBoard as it pertains to fluid temps and btu/H/sq ft.



Just guessing, but I suspect you are getting some deflection in your rig, which is causing you to come up short. Maybe you should consider a rolling press instead of a fixed vertical press. I dunno.



I don't know how yo would do it, but these plates had an Omega shape to the tube receiver, which makes for an excellent fit. The tighter the fit, the better the conduction, the better the performance.



You might have noticed that the middle picture has no insulation in the cavity. That is because I wanted the heat to flow bi-directional. The other side of that wall is a knee hole at a log bar in the dining room, and I wanted my guests to feel the heat as they are sitting there drinking their morning Joe, looking out at the lake.



It's all about human comfort...



A word of caution on radiant walls. To avoid potential tube hits, I marked a "no screw zone" on the floor where the return bends were located, and also developed a "Storey pole" showing exactly where we COULD put screws (green X with circle around it) and where we COULDN'T (red X with circle) put the screws due to tube being placed there. It requires forethought but will alleviate the possibility of having to dig into the finished wall to effect a repair from a self healing screw hit in the future (rust never sleeps).



All of my hydronic circuits are controlled with non electric TRV's and the fluid is being pushed with an Alpha.



Enjoy!



ME