I will be using a mixture of laminate flooring, carpet, and vinyl tile. I know for the vinyl I will need 1/4" luan, but what about the carpet and laminate. Can they be installed directly on top of the 3/4" sleeper/tubing/plate sandwich?

Personally, I refuse to have tubing installed without SOMETHING hard between the tubing and people's feet. I just have nightmares of soccer cleats or kitchen knives or a baby grand piano...

I've never heard of such a story mind you, but still I think it's prudent to have a solid underlayment between carpet and the radiant. Even just a 1/4" hardboard or what have you.

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Northeast Radiant Technology, LLC
-=RFH Design, Supply and Consultation=-
RPA certified Radiant Designer
http://www.NRTradiant.com
rob@NRTradiant.com

Ditto on something between tubes and carpet...the luan will work fine for this, or I've heard of tempered hard board, like peg board...advantage being your holes for fasteners are already drilled, and you can see the tubes...no OOPS, get out the couplings.

I'd think twice, though, about luan for under vinyl. It requires so many fasteners, like crown staples every 4" - 6" in order to be firm and not floppy for under vinyl, that you'd be hard pressed to not hit any tubes. I think 1/2" or 5/8" plywood would be a better choice for underlayment beneath vinyl.

OK, so I need something between the carpet and tubing. But it is ok to place a floating laminate floor directly on top of the tubing? Is that right?

quote:

I've never heard of such a story mind you, but still I think it's prudent to have a solid underlayment between carpet and the radiant. Even just a 1/4" hardboard or what have you.

[/B]

Wow, I like that idea of using 1/4 pegboard so the tubes can be seen. I recently completed the Warmboard installation on our 800sf second floor. Even though the Warmboard folks say you can put carpet right over the panels and tubing, I'm not sold on the idea. It seems like tubing damage and odd wear patterns in the carpet would both present distinct possibilities. I've been bothered though by the idea of covering those tubes. I had been thinking about trying to to transfer the tubing layout to luan plywood as its installed. The pegboard would make this a non-issue.

I did however check the website for my local lumber supplier and they specifically advise against using tempered Masonite as an underlayment. I assume the issue is water resistance. Since this is just a bedroom area, I'm thinking it might not be much of an issue. Have others on the list used Masonite as an underlayment for carpet?

How would you advise laying it over Warmboard? - glue, nails or both...

Anything between the Warmboard and underlay? - 6mil poly, building felt, etc...

Thanks.

Richard Johnson PE
Camano Island, WA

While it may seem on first thought that the tubes in Warmboard under carpeting may be at some risk, as a strict engineering proposition they are not. The tubing is narrow (5/8” o.d.), and quite tough. It forms in essence a near rigid arch when buttressed by the “U” shaped grooves it is nestled in. Because the question of possible tubing damage is reasonable to ask, we have of course tested the for the possibility of damage from chair legs, pianos and the most pointy of high heels regardless of the weight of the person wearing them. A two hundred pound load was placed directly on a bare tube through a 3/8” x 3/8” block for one hour without leaving even a mark. This is the equivalent of a two hundred pound person balancing not only on one leg but on the heel only of a high heel shoe perfectly positioned over a bare tube for an hour. This constitutes a worst case scenario because chair legs and piano legs are wider than the 5/8” groove width which means their load is carrying by the adjacent plywood not the tube. While carpet and pad are pliable, they do in fact provide further protection from all such loads.

Let me assure all readers of this bulletin board that carpet and pad have been installed in direct contact with the Warmboard surface literally thousands of times with zero incidence of tubing damage. I personally have lived in a Warmboard home for eight years. My entire second story is carpeted with the sort of carpet (smooth plush) that would show any surface problems should they be evident. The carpet is installed directly to the Warmboard with only a 1/4” slab foam rubber pad between carpet and aluminum/tubes. The tubing is absolutely undetectable visually. There is not even the slightest print through or wear marking and the tubing is certainly undetectable to the your feet or other means of detection. Adding a structural layer between Warmboard and carpeting only adds labor and material cost while degrading performance. We at Warmboard strongly recommend against it.

[This message has been edited by Terry Alsberg (edited 01-05-2005).]

[This message has been edited by Terry Alsberg (edited 01-05-2005).]

I was waiting for that post Terry

I know, I'm probably being paranoid... but people do have sharp pointy things in their houses and I hate to think of what could happen.

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Northeast Radiant Technology, LLC
-=RFH Design, Supply and Consultation=-
RPA certified Radiant Designer
http://www.NRTradiant.com
rob@NRTradiant.com

Am I all wet here, or would adding peg board be like adding a whole bunch of air insulators? Seems to me the air in the holes would act as insulation.

From what Terry is saying it sounds like it would be ok to lay the carpet and padding directly onto the sandwich. I don't see any difference in doing that on a "do it yourself" sandwich compared to the warmboard. Any other opinions or experiences with this? To add another layer is going to add more cost and install time. Is it necessary with a "DIY" sandwich?

the risk would be equal if and only if the grooves between sleepers and relative height of the sandwich strips to tubing height were quite similar to warmboard's tubing grooves.

that said, as I've noted, it's not a risk I am personally comfortable with even with warmboard, but as Terry has noted, it's not exactly a widespread problem that I'm fighting here. I just can't see it being prudent to leave tubing basically exposed in a floor.

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Northeast Radiant Technology, LLC
-=RFH Design, Supply and Consultation=-
RPA certified Radiant Designer
http://www.NRTradiant.com
rob@NRTradiant.com

I'm thinking out loud here... If it is the case that you should have a layer on top of the tubing when doing a sandwich install, you might as well do staple up. What would the difference be? Either way you have a layer on top of the tubing, but with staple up you don't need sleepers. Also, your layer between the finished floor and tubing is the existing subfloor. So your taking out the cost of two additional layers. Am I missing something here? I was shying away from staple up, because I thought the sandwich would make a better all around system, but maybe I was mistaken. Please advise. Thanks.

It's a good question. Part of the difference is the heat transfer to the plywood strips the plates are on top of will "reconduct" to the layer above where the plates are not installed, whereas in a staple up your downward heat transfer is not "recaptured" in this manner. That's not a scientifically rigorous explanation but it should be good enough to get the idea across.

Also wood floors do not need this additional layer, and tile floors you are pushing only through the tile backer instead of backer + subfloor.

All in all, above the floor does perform much better than below the floor, even with the additional layer. Also remember that additional layer under carpet does not need to be 3/4".

Or, you can side with Terry and skip the additional layer! Personally, I'd skip the carpet. Indoor air quality will thank you!

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Northeast Radiant Technology, LLC
-=RFH Design, Supply and Consultation=-
RPA certified Radiant Designer
http://www.NRTradiant.com
rob@NRTradiant.com

NRT.Rob,
In your comparison are you talking about staple up without plates? Wouldn't staple up with plates be almost the same as sandwich with a layer of plywood on top? I hear what you are saying on the carpet, but I can't talk the wife out of it. She wants carpet in the living room and bedrooms. So I've gotta work around that and I really like this radiant heat. Thanks for all your responses so far.

nope, I'm talking about plates under floor vs plates above the floor.

To lose heat so it is NOT heating the floor above, in a sandwich you have to heat two layers of plywood; at least one of which is also helping you heat the floor above via direct conduction. In underfit plates, lost heat is only warming air before it is "lost" downwards (nevermind infiltration possibilities).

It's a bit more thermally efficient, in other words. Of course, much depends on your choice of carpet and pad, and Terry's setup is ideal in that respect; slab rubber pad.

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Northeast Radiant Technology, LLC
-=RFH Design, Supply and Consultation=-
RPA certified Radiant Designer
http://www.NRTradiant.com
rob@NRTradiant.com

Thanks for clearing that up. I looked up the R values for different thicknesses of plywood. 1/4" = .31 and 3/4" = .94 so that is a pretty big difference as well. Now about this padding, is there a big price difference between the normal carpet padding and the foam rubber slab? Is the foam rubber slab widely used?

not sure on price, terry might know. it isn't widely used, but it sure should be!!

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Northeast Radiant Technology, LLC
-=RFH Design, Supply and Consultation=-
RPA certified Radiant Designer
http://www.NRTradiant.com
rob@NRTradiant.com

The problem with some (most??) carpet installers is that they really don't pay much attention to the padding. That's what got me into my mess. I clearly specified in-floor radiant heat, and that special padding would be needed, and was assured that the padding I was getting was OK (NOT!). You may want...no, you NEED to be specific about the padding. Maybe not all carpet vendors are the same, but almost every vendor I talked to didn't seem to differentiate the padding.

-Darryl

Rob,

Why not just nail a thin aluminum plate over where the tubes run? Sure its a pain, but is it any more work than covering the whole floor with something?

One problem I suspect might be that one could feel the edge where the plates (both the omega and any protection plate) edge was but assuming that could be handled any comments on how this stacks up against an additional layer?

it's not a sufficient measure for heat transfer, if you're thinking that would replace omega plates. You are really limiting your direct conduction that way (not much direct contact with the tubing).

As a protective measure, I suppose you could, not sure how the price of metal plate would compare to an underlayment though.

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Northeast Radiant Technology, LLC
-=RFH Design, Supply and Consultation=-
RPA certified Radiant Designer
http://www.NRTradiant.com
rob@NRTradiant.com