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What’s the best way to get hardwood over RFH?
Installation of PEX between sleepers with a 2″ pour of lightweight concrete creates a problem for installing T&G hardwood. When using #1 or select grade, you always have a lot of random and shorts. I was planning to install the sleepers 16 oc and that doesn’t provide a very stable nailing surface.
Installation of 3/4 ply over the sleepers provides the best nailing surface, but increases the R value over heating surface!
I understand that glue down is NOT recommended over a lightweight slab!
A staple up job still leaves me with the stackup of ply & hardwood. Plus the rigidity of only using the floor joists for routing… ie no custom perimeter zone covering!
Is a floating floor possible? I know nothing about this type of install. I guess every pro-basketball court goes this way…. However, I don’t have one of their salaries.
Your help is appreciated….
For other background info checkout:
www.rpa-info.com (see bulletin boards)
www.woodfloorsonline.com/techtalk/woodwater7.html
Replies
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Hey Craig??
What's to bitch about? Check your design. Falling a little short?
Design around it. Don't chicken out on the supplemental.
Have you considered a dry installation on top of the subfloor?
That way you can use all "the shorts" you want to your hearts' desire.
Oh, and by the way. Why is that link at the end of your post so important? This link led me directly to a "sales pitch" for a company that I suspect you may be personally involved with.
For the sake of truthfulness, son, be man enough to fly your flag at full mast and not cower under a false premise when posting here for the first time. At least let us get to know you before you start unloading your wagon of elixirs on the town square. What I thought was really clever of you was to mask your intentions with a link to the RPA's site.
Jeffie here!!!
*Sorry to lead you through a sales pitch, I thought it to be quality info on woodflooring.... and better info on hardwood than the RPA site. My flag flies high.But I am interested in your comment about a dry installation on top of the subfloor... I don't know what that means? I'm all ears...However, I'm still stumped on nailing to sleepers... is it OK to add another 3/4 ply on top? It seems like a lot of R value to push the RFH. Higher temp h2o, more insulation, slower recovery from set back.... etc.This type of hardwood install must be common, but I havn't found anyone with direct experience....
*Craig,This is one way to do a dry system, floating hardwood or naildown.
*Jeff,Is this system more noisy (expansion) than other methods and, if so, do the plates contribute to the noise? What are the consequences of skipping the use of the plates?TIA, Jerry
*Jerry,There is always the possibility of noise with plates. The thinner gauge plates seem the most prone to "popping" noises due to the expansion of the regular pex tube.Some ways to reduce or eliminate noise: 1) Use system reset which encourages modulating the supply water temperature to slowly increase and decrease water temperatures. This will also help to keep the circulation constant. 2) Use pex-al-pex with plates. Pex-al-pex has a much lower coefficient of linear expansion. 3) Using the thicker extruded plates.I would not recommend skipping the plates with the dry system under hardwood. Thermal striping will be very noticeble across the hardwood surface and could cause problems with the dimensional stability of the hardwood. I suppose if one was to use 4 inch centers on the tubing, you may get away with it. For ease of placing the tubing and dealing with the return bends, 4 inch centers is not an easy job.My installation of choice when the dry system must be used is pex-al-pex with plates. Six inch on center spacing and definitely use variable speed injection mixing with indoor reset.My real choice for under hardwood is a poured floor underlayment without plates and six inch centers. I would still use VSI mixing with indoor reset. A good prefinished floating hardwood for the finish.The poured floor could either be a gyp product or a batch plant made lightweight concrete. Lightweight concrete is approximately 1/4th the cost of gyp in my area.Jeff
*Thanks for the DRY option.... I had not explored using plates.I got a little mixed up on your last post.... I lost you on the 6" centers with a floating floor. Is that sleepers or PEX at 6 inch centers??? Sleepers and a floating floor didn't make sense.I think I'm leaning toward a floating floor... but I understand a vapor barrier or foam spacer is typically used. That adds to the "R" stack up.... Any thoughts about a floating floor directly on top of the RFH?Help me on the lightweight concrete option.... does it offer better stability? What about shrinkage? Any special talent required??THX...Craig
*Whether it be the 'dry' system or the poured floor underlayment, I would recommend 6" OC.The real design trick is how the loops are configured in relation to the components of heat loss within the zone. That in itself is worthy of its own chapter.You just keep diggin' Craig. Eventually you will get it all figured out.Jeffie
*My plan is to go with a floating floor on top of light weight concrete. I'll let the RFH guy figure the BTUs and layout. Thanks for all your pointers.Now the question is Oak or Bamboo.....
*Mesquite with copper inlay.
*Jeff, a coupla questions.I built an art studio for my wife this past summer, and put in a real crude, DIY hydronic floor heat system, just to see what it felt like. (Gravel layer to discourage gophers > 2''foamboard > gravel > hogwire to tie PEX to > gravel > 3/4" MDF. )Well, it works pretty well; in fact, my wife now says when we build our house in a coupla years, we MUST have floor heat. Well, I HATE slabs; I mean, how can you go back and add all those wires you always need for everything new?But, I gather that the most "efficient" way to do hydronic floor heat IS a slab? Topped with ceramic or stone? Should I just run conduit everywhere so I can later add wiring to heart's content? It appears that floor heat on top of typical joist/crawl space is very problematical.Alternately, can you get almost the same "comfort" of floor heat by having very well insulated floors? (I know this is one of those judgement calls.) I ask this in part because, here in central valley CA, air conditioning is pretty important. (Anyone out there with a Smartcool system?)Hoping you and/or others who've been down this road will respond.
*Jim,What do you mean when you say "It appears that floor heat on top of typical joist/crawl space is very problematical""?I wasn't aware of any problems. Enlighten me.Jeff
*Jeff, I thought the contents of this thread indicated that. Or maybe I should have specified that "wood floors on top....were problematical"?Or, starting fresh: Is it true that RFH is most efficiently and economically accomplished via insulated slab, topped with stone or ceramic? Or not?Is it true or not that using joist/crawl space and wood floors (even in new construction) is asking for SOME problems? MANY problems? Depends on RFH contractor and GC and flooring people?I've read about problems with gypcrete, nails through PEX, popping (noisy) heat shields, etc. Maybe, as I asked, it's just a matter of getting good people to do work?Jim
*Jim, Typically, gypcrete installers arrive on scene after the interior walls have been framed. Thus, their pours will be inside the sole plates of the walls in the various rooms, with the finish flooring on top.So...if you have a propensity for drilling through finished floors, slabs could indeed be a problem. However, fishing wires through the plates, then through the stud cavities remains...same as it ever was...As to efficiencies of heat transfer, the lower the R-value of the floor section, the better. Makes sense. I'm not as biased as most against under floor staple-up. I've got it in my own house. Under floor staple up with NO heat transfer plates, 3/4" ply sub, 1/2" ply underlay, hardwood strip floor, and in a few rooms, rug pads and oriental area rugs. You want R-value, I've got it where you don't want it. Under the tubing, friction-fit between the joists I have half-inch foil faced RFBI and below that 6" of FG. Water circulates at 95-100 degrees. Toasty floors, even with all the "R".Had friends over for dinner tonight, first thing they did upon entering the house was lay down on the warm floor. Luckily they kept their clothes on. They're in the design process for a new house for themselves. Main reason they're moving/building? They want RFH. As you and your wife discovered, it's good stuff.
*Thanks for the input, Mongo. I've wondered, too, about the value of those heat transfer plates; I bet if you could figure a way to get an inch or so of nicely packed sand in there between your RFBI und underside of floor....Yeah, as I said, we're sold on the comfort level; I'm just wondering about slab vs crawl. (Where was it I read about some guy trying to run speaker wires from crawl space, and drilling up 6" through subfloor without coming out, and then finally realizing he was far enough off that he was coming up through a big old claw-footed table leg?)The problem (it seems to me) with RFH is that it's still so relatively new that procedures are being changed on a seemingly daily basis. Every time you turn around there seems to be a new way to do it. Now there's that company that makes a sleeper system to be used on top of subfloor and under hardwood. Sounds great; does it work? Keeping everything completely under the floor, as you have, and thus accesible, seems pretty smart, especially if you keep track of exactly where those plates are! (Maybe this is a supplement to John Abrams' "Owner's Manual".)I was willing to do my usual jackleg install in the non-permitted studio, just to see how it felt, but when we build a real house, with multiple zones, I'm going to want to hire a professional to do it right. Guess I'll just continue to keep my eyes peeled, and take my no-doze while waiting for downloads, right here.
*I've just read through the messages regarding RFH, but not sure I've seen them all. Regardless, I'll throw in my 2 cents. I put RFH in the concrete slab in my new shop and love it because it eliminates stirring sawdust by a forced-air system and also hot surfaces. The only disadvantage is the slow response time in warm-up if I turn the temp down for an extended absence.This summer when I build our house, I intend to use RFH in it--I'm sold on it obviously. But at a recent home show, I just ran into a new product that I've not seen any reviews of and wonder if any of you have used it. It's called "warmboard" and is basically aluminum adhered to >1 inch chipboard (I'm not sure about that, but not plywood). The aluminum can be folded and chipboard indented to provide whatever groove pattern is needed for holding the PEX tubing in the engineered arrangement. The warmboard is used in place of subflooring and allows carpet, tile, laminated flooring, etc. to be installed directly on top of it. I have some concerns about potential punction of the PEX tubing, but otherwise the product appeals to me because I can install it myself. This saves the cost of bringing in a gypcrete contractor, larger joists and double bottom plates to hold the gypcrete, etc. Anyway, anyone out there know about this product?
*Burr,I am familiar with the product. What specifically would you like to know about it? I do take exception with the perception that 'any' floorcovering can be installed directly over it. Other than that, you must plan extremely well when incorporating this product. Simply because the nature of the product and application can be counter-productive to tubing layouts that target the heat loss components. Of course a knowledgable radiant designer can overcome the limitations of WarmBoard and give you a system that works extremely well. Look at the preconfigured piping path that this product determines and ask yourself, is the warmest water always presenting itself to the highest heat loss building components?There is more to a heating system than the ease of DIY installation and saving a buck or so. Why get yourself in a position where you will save a few bucks upfront but the ultimate cost in energy and comfort will grab your pocketbook for the every month for the next 360 or so months?No kidding, do the figures.Jeffie
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What's the best way to get hardwood over RFH?
Installation of PEX between sleepers with a 2" pour of lightweight concrete creates a problem for installing T&G hardwood. When using #1 or select grade, you always have a lot of random and shorts. I was planning to install the sleepers 16 oc and that doesn't provide a very stable nailing surface.
Installation of 3/4 ply over the sleepers provides the best nailing surface, but increases the R value over heating surface!
I understand that glue down is NOT recommended over a lightweight slab!
A staple up job still leaves me with the stackup of ply & hardwood. Plus the rigidity of only using the floor joists for routing... ie no custom perimeter zone covering!
Is a floating floor possible? I know nothing about this type of install. I guess every pro-basketball court goes this way.... However, I don't have one of their salaries.
Your help is appreciated....
For other background info checkout:
http://www.rpa-info.com (see bulletin boards)
http://www.woodfloorsonline.com/techtalk/woodwater7.html