Radiant tubing above or below subfloor?

Unknown

Well I didn't say it was a BIG difference, but joist trak has the edge (though, how are you reading those charts to a resolution of 1 degree??). You're right though, strictly apples to apples it's not a huge difference. I ballpark it at five degrees but we only design in five degree "chunks".

In practice though, You can much more easily run lower dt's and get more output at similar water temps with 3/8" or 1/2" tubing than you can with 5/16" though, and you can save about two bucks a square foot doing it. I design around 20 standard too, but I up to 10 dt in the highest water temp areas to keep overall system temp as low as possible. Can't really do that with quik trak. with flow balancing taken into account, that's another 5 degrees in water temp on top of whatever difference you get otherwise.

If quik trak were faster to install or cheaper, I'd be more forgiving; it's pretty heavily priced for what you get though, and you can get a better system with heavy plates, in the end.

I suppose you could argue for just putting the plates in the high load room and doing quik trak everywhere else if you really insisted ;)

Paul Formisano, P.E.

Radiant tubing above or below subfloor?

105414.1

I'm a Mechanical Engineer building a new home in Massachusetts and it's almost completely framed at this point. I want to use hydronic radiant tubing under the floors for heating. I've seen the Uponor PEX tubing and the quick track which sits on top of the floor, as well as the joist track that sits below the floor. I called Uponor and they said it doesn't make much difference which type is used, but quick track is more expensive for material. Does anyone have any experience with installation of either of these types - would you rather do one over the other? Are there any pitfalls I need to be aware of? Are any other brands of PEX better?

I'm not planning to set the tubing in lightweight concrete. My finished floors will be mostly hardwood, with tile in the kitchen and bathrooms. Any recommendations for the type of wood floor (engineered, floating, nailed, glued)?

After doing some research, I'm favoring the quick track because the response time might be a little better and the water temperature can be lower. Any comments?

Thanks,

Paul

ALH_4

Radiant Floor Methods

It depends on your criteria. Above floor methods require more labor and materials to install. If you want performance and cost is less of a concern, above-floor Thermofin-U is a good option. Warmboard is a good product also, although it sounds like your project may be beyond the point where Warmboard is still an option.

Below floor methods with extruded plates performs nearly as well as above floor methods. The installation goes more quickly and it does not affect your finished floor elevation. This leaves a bare subfloor for installation of your finished flooring. I would encourage the hardwood installers to use fasteners that do not penetrate the subfloor to avoid the possibility of hitting a tube.

In general, my preference is below floor Thinfin-C as the best balance of cost and performance.

eluv8

above or below installations

My first choice is usually gypcrete. I would then vote below floor IF you can get in before the electrician, hvac, and plumbing contractors, But then you are exposed to the other trades and will most likely end up moving and repairing tube. So, it really depends on the jobsite and what is going to be in your way underneath. Beams, plumbing, heating, electrical, fire sprinklers to name a few. Why are you apposed to gypcrete. Its a great sound barrier, floor stiffener, thermal storage, trades are used to installing on it, fast tube installation, the only negatives I can think of is either double plating the bottom plate or raising your floor 1-1/2"s and the time for the gypcrete to cure slows the contractor some. A common mistake with gypcrete and wood flooring is not fully curing and removing the moisture prior to stocking and installing the wood floor, and not laying wood strips inbetween the tubes to nail to.

Ron Gillen

Thinfin and Oak

In my own home I used 3/4" Fir tongue and groove subfloor with Thinfin plates under. 3/4" oak flooring with 1 1/2" Bostich flooring staples (they don't penetrate the subfloor). 1/4" Hardibacker and 3/8" porcelean tiles. I like underfloor as it makes flooring install easy.

RADGUY

Above or Below

Paul,
I would highly recommend that you stay on top of the subfloor. The typical R-value for the subfloor is approx. 1, thus attaching underneath will lead to higher water temperatures (anywhere from 5-20 degrees depending on the home). I would also recommend Viega’s Climate Panel over the QuickTrak as both are manufactured by Viega (in Acton Massachuetts). A system on top of the floor will cost more up front than underneath however I would say that the installation would be easier (though maybe not faster). I have installed this system before in NH and it is really pretty smooth.

joel_28

Viega

We have installed over an acre of climate panel in Mass and it much better than going under the floor. Far faster response,lower water temps,easier to instal a nailed down floor.It is also MUCH faster to install than bellow the floor. If your project is in our service area we'd be happy to help. boucherenergy.com

Unknown

this is not entirely true.

if you are comparing to plateless suspended tube, you're right, but if you compare to a plated joist system with proper plates, the plates will beat climate panel every day of the week, by any measure you care to measure, except MAYBE in initial response, which isn't a particularly important measure anyway.

Most installers I know that have done both end up going back to heavy plates in the joist for most projects. speed is comparable, price is a couple bucks a square foot less, and water temperatures are better. If you're going to use a panel, there are several better for not that much more money. If you need to save money, use the heavy plates in the joist.

the only thing climate panel/quik trak have going for them is a 1/2" profile. if that's what you need, then there you go.

WV EGBERT_2

Basically the same

Rob,

according to my charts from Uponor, there is not much difference between the two as far as output goes. What charts or references are you using?

Joist Track- 8" o.c. , 65* room setpoint , R.1 finish floor ( includes subfloor) 125* supply fluid temps @ 20* delta = 22 btu/h/sq.ft

Quick Trak- 7" o.c. , 65* room setpoint , R.1 finish floor , 125* supply fluid temps @ 20* delta = 21 btu/h/sq.ft

So , when you consider that plates are pushing thru a subfloor and still able to give the same as an above floor system, then yes . But however, a moot point because after all it's the output of the finish floor that matters, not the the method, or components.

Personally, I use both, but do end up using more plates. When on a smooth slab or floor and no obstacles , on a scaffold, they (plates) go up pretty quick. When working around framed walls , going up and down a ladder kills the knees, and takes longer. Thats when QT has an advantage as you can install the multi panels pretty quick.
Btw, with plates, I always use 3/8" tubing, just easier to weave in between the joist than 1/2"

Devan



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WV EGBERT_2

btu/h/sq.ft

the difference was about 1 btu per sq. ft. difference not degree. Yea , that would be pretty hard to read.

I also like to make my own above floor panels, by ripping 8" sleepers, and installing lightweight plates in between.

I buy my light weight plates from a couple of guys I know up in Maine ; )

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