RFH – Warmboard, Quick Trac, Viega Climate Panels or staple up?
richardi
| Posted in Energy, Heating & Insulation on
I’ m having a house built which will have RFH in the slab (lower level) and well as under the hardwood (bamboo) and tile on the main floor. I have received quotes from a couple of different subcontactors, each recommending a different method of heating the floor.
I’m sure each has its good points as well as its bad points, as well as costs. So, how does one decide which method/product?
Also, should I nail down the bamboo flooring or float it?
Thanks
Replies
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Starting from scratch, you have all the options available. Considerations include design/selection of the flooring, which impacts the water temperature, which impacts the efficiency of the (most efficient) boiler.
Staple-up - that is tubes installed under the subfloor - require the highest water temperatures to get the same amount of heat into the space. With a condensing boiler, running the lowest possible water temperatures gets you the greatest efficiency out of the boiler.
In the slab, you will (or should) have the tubes imbedded in the concrete, tied-off to the mesh or re-bar.
On floors above grade, the type of flooring desired dictates some of the options. Tubing imbedded in a lightweight concrete (like Maxxon Thermafloor) are great for tile, floating/engineered wood, sheet flooring and carpet. This is arguably the prefered method for both cost, thermal mass and ability to use the lowest supply temperature. Staple up is the cheapest, least desireable method, usually used for retrofits. Nailed wood flooring requires the ability to see (and avoid) tubing, so a Warmboard or Quicktrac is necessary/prefered. These work well, but cost the most.
With different flooring selections and/or installation methods, you will need to control each type of flooring with a different supply temperature.
Look up the tubing manufacturers, like Uponor, and download their design guides. It has been sometime since I was directly involved in this industry, some my understanding and knowledge of methods may be outdated. However, if it were my new house, I would staple 1/2" Uponor PexA to the top of the subfloor and cover it in a 3/4" layer of ThermaFloor and float the wood floors.
if you were my client I'd suggest pex tubing in a full slab and floating your bamboo. The downside is the extra framing needed to support the weight of a concrete slab, but it's trouble free and the extra mass in the floor evens out temp swings throughout the day. It's what I'd want in my own house.
Cheers
this is the hierarchy in terms of output from best to worst for the listed methods plus an overpour as mentioned by idahodon:
1. Basement slab with no floor covering
2. Warmboard
3. Overpour concrete with finish floor.
4. Staple up with heavy gauge aluminum plates
5. quiktrak/climate panel
6. staple up without plates (very weak, rarely the right choice)
always float your flooring over radiant if you can, if you are using a method you could puncture otherwise. joist mounted is usually safe from that.
Since #5 is one of the more expensive but its output isn't that great, I would usually discourage them.
#2 is great if you are paying for installation labor or want the best output in a suspended floor.
#3 can be very competitive in some cases but not so much in others. depends on what you have for gyp applicators in your area. I would normally discourage real concrete in that case if you are using sleepers, as it shrinks and you lose a lot of conduction that way. gyp won't shrink. without sleepers (with floating floors) that also isn't a problem.
#4 is pretty good, if you can't or don't want to build on top of the subfloor or must use nailed wood and absolutely don't want to risk punctures.
I have lately been doing more #6 with panel radiators tied in to get an inexpensive low temp floor conditioned system. but then you have visible radiators as an element of the design.