The tune has changed, all the flooring suppliers in my area are advising not to use 3/4 hardwood over a radiant floor. Sure there will be some expansion and contraction but does this warrant going to an enginerred floor? Will appropriate acclimation suffice?
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We installed 3/4" ash over radiant heat about 9 months ago, and have not had any call backs yet. I was'nt really sold on the idea of installing wood floor like this, but the Owners insisted. Anyway we will keep our fingers crossed.
MB
My understanding is that the fluid in the radiant tubes must be kept low enough that the flooring will never get too warm - maybe 85 degrees max. - about as hot as it would get if bright sunshine heats it up. I am installing bamboo flooring over radiant tubes in my own house, (it is not done yet), but we choose a bamboo that has three plys with the center one being 90 degrees to the outer ones just to make sure it doesn't move too much. It is still a T & G plank, nailed down. I would have used solid hardwood though if the bamboo weren't available.
We did a bamboo gluedown. No measurable expansion/contraction. RFH is 115 throughout house. I'll throw out for your consideration that indoor humidity makes as much difference as the heat. I keep the house between 35 and 50% year round. If it varied be/t 20 and 70, I'd expect more of an effect on the flooring.
From what I've learned....and radiant heat isn't big here in Florida.... Be very careful with cranking on the radiant heat as it has to go on very slowly in the beginning. There's more information somewhere on my links page regarding the issue.
Ken Fisher
http://www.floridawoodfloors.net/links.htm
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Edited 9/22/2002 7:00:25 AM ET by HARDWOODGUY
Ken, what's that mean in practical terms? My tank is set to 115, and that's the temp it's gonna be. Takes hours to get that heat through to the floors. Don't have an option of having a variable set point.
And I am specifically not speaking of a hardwood situation. I know my local hardwood flooring center recommended against gluing wood on RFH (didn't wanna sell me the glue for it), but when I said bamboo, they said, oh, ok, that'll work.
Does your comment relate to this statement from one of the sites: YOUR HEATING SYSTEM NEEDS TO BE DESIGNED TO EASILY HEAT YOUR HOME WITHOUT EXCEEDING AN 85 DEGREE FLOOR TEMPERATURE? I've heard similar, but in a different way. I was contemplating an in-slab temperature sensor (to limit the effect of solar gain on an ambiant temp thermostat), and the advice was to set that for about 10 degrees above desired room temp. That's entirely consistent with this 85 degree suggestion.
Edited 9/22/2002 8:27:56 AM ET by Cloud Hidden
"I keep the house between 35 and 50% year round. If it varied be/t 20 and 70, I'd expect more of an effect on the flooring."
True. But when it's -20F outside, it is hard to keep the indoor RH up. No less important, just harder. So in my own house, RH varies between 18% and 75% winter to summer. Which means gaps towards the end of winter. 3/4 solid wood, locally milled birch, 4.5" width. I'm sure we'd get some gaps regardless of the heating system, I run my RFH pretty cool, around 95-105. Doing a guest cabin right now, going with the Prego stuff for stablity, and lower insulation between slab and room.
Cloud, couldn't you cut in a tempering/mixing valve? $75 and you get to set the temp going out to the RFH. Cranking it up makes in more responsive in cold weather and turning it down makes for less overshoot in mild conditions.
David Thomas Overlooking Cook Inlet in Kenai, Alaska
-20?!?!?! Ha ha ha!!!
Being inherently lazy, I don't want to have to adjust anything, even from season to season. Also, if I get hit by a beer truck, I want DW to be able to go at least a year w/o having to learn how everything works.
That said, we do have a set-point controller on our system. Experience shows that our slabs don't do much heating with water temps in your range. The 115 works well and efficiently (and is about all out GSHP can maintain with our btu requirements) and I can safely leave it there year round. I guess we're just fortunate with the humidity (some of that is a credit to the nature of this house's construction--be/c neighboring houses aren't operating in so tight a range--and some to the climate). I'd expect to see our flooring react more than it does, either if the water temps were in the 130+ range or if our humidity range was wider than it is. I am thrilled that the humidity is as controlled as it is, for the sake of the flooring, doors, and all the furniture! :)
You realize that my daughter is growing up not knowing what it's like to shuffle your feet on carpet and give someone a shock?
You realize that my daughter is growing up not knowing what it's like to shuffle your feet on carpet and give someone a shock?
Cloud, that brought a smile to my face. Back when my daughter was two we lived in a house that had some carpeting. She'd call out "ooohhhhhh...electric kisses" every time she got zapped when giving a kiss. The good old days. Then again, all of the days have been pretty darn good.<g>
Hardwood strip flooring is appropriate over RFH.
More important than acclimating the wood is properly designing, installing, and running the RFH setup.
In a nutshell...a very small one at that...
RFH is kinder on hardwood over a slab (or warmboard-type subfloor/underlayment) than over an under-subfloor staple-up.
You may want to consider running the tubing loops closer together. This may allow a lower design temp which may be easier on the flooring, eliminating striping.
Outdoor reset.
I hear voices calling...(real ones <g>)...gotta go.
Last item...engineered 3-ply REAL wood flooring has come a long way over the past 5 years. Some good stuff out there. Careful with gluedowns. If the temp gets too high, the glue can crystallize, become brittle, and fail.
We have been putting in hardwood floors over radiant heat for at least eight years now without a single problem. Of course we explain to people even if they are not using radiant heat that they are getting a wood floor. Wood moves and if the boards are wide it moves more. We now use a radiant system that goes through drilled holes in the center of the joists and has little aluminum fins attached. This uses less tubing and the floor can be nailed without the worry of puncturing the tubing.
>> ... a radiant system that goes through drilled holes in the center of the joists ...
Is there any place I could see pictures or drawings of this system?