hello all. i have been following this board for a few months now, and have even been in the old archive posts. very educational discussions here, i think i have learned alot about this.

i am attempting to find a subcontractor to estimate/bid a infloor heating install for our basement. the floor is over 2 years old down there, and is just a concrete slab. we have not had any problems with water in our basement and there are no signs of water that we can see.

i have framed the walls and i am now concerned about the corresponding raise in the floor height (steps may have to be raised, doors, etc) with infloor heat.

some contractors i speak with say that uponor quicktrak can go right over the slab (is this true?) others say i need the foam and a plywood subfloor nailed down first.

i have even contacted the manufactureres directly tring to get a lead on a qualified/certified installer in my location (nw suburb of mpls/st paul area) for all the retro fit products. they usually refer me to a sales rep, who doesn't return my calls. or, the sales rep sends me to a warehouse that doesn't sell to the general public. or, one time i was sent to a installer that had since dropped their product line.

i just want to know if anyone has installed quicktrack over a slab without a vapor barrier or plywood subfloor? is raupanel a better product (as some on this board have mentioned)? is anyone interested in bidding this job?

frustrated in MN
wb

It would work, it's just not "ideal". You would have aluminum on the bottom of the panel in direct contact with the concrete. Look at the Roth panel, as it is better suited for concrete floor applications.

it *might* not work, if you have heavy downward losses from the slab. Generally it would but as guest says, it's certainly not ideal.

If the existing slab is itself already insulated though, I wouldn't worry about it as long as the space will be consistently heated.

If neither of those assumptions are true, I would definitely consider roth panel.

If floor height is an issue, you alleviat the problem by first applying a new "paint-on" insulator and then glue down low voltage radiant Zmesh bronze screen directly on top. The 2 products together won't add 1/4" to your floor height thus removing the cost of adding the board, boiler and pex. It will be as efficient (though some seem defiant to argue the point) as any other product on the market and much more controllable.

Wouldn't the aluminum oxidize against the concrete on the bottom of the quick trac? JB

quote:

you alleviat the problem by first applying a new "paint-on" insulator

Not trying to start another argument here, but that sounds more like a paint-on vapor barrier. If it truely insulated to any degree whatsoever, I'd paint my house, in and out, with it. More magic hocus-pocus, unless someone has a link to actual data on it?

NASA originally designed the product. It does what they say it does. Here's the link where you can download their test results and spec's and Guest....money where your mouth is??

http://www.thermotekltd.com/

that's a radiant barrier, according to the testing PDF. We've gone through similar issues with "radiant barrier" products marketed for under slab use that made audacious claims for a long time before getting shut down by studies geared for that application.

In this case, if you're gluing directly to it and the whole assembly is only 1/4", then you are gluing your mat to a conductor, not an insulator.

Here's the testing results PDF from that website: http://www.thermotekltd.com/images/test_summaries_12_05_06.pdf that explains how it was tested.

I guess you don't understand it's application. It's a heat reflector. Heat reflectors require an air gap to reflect.

Think of it like this... Aluminum is a good reflector. But, coated on the bottom of a pan, makes a great conductor. Thats Money

Yup, makes sense...I'm working on it. I'll get back when I have a clear answer.

out of curiousity, if you had to use a different insulation method (build up is of no consequence), what would you do? Is it ok to put these mats directly on top of, say, rigid foam?

sorry, not mats, I know

Yes. Picture bronze screen door screen, only 9" or 12" wide. Roll it out, staple, or in this case tape it down to the foam, fold it over twice at the wall to return and do the same thing through out the space until covered with 2" spacing between runs. You can staple or nail or screw through it all you want as long as it isn't grounded. Cut holes in it for outlets in the floor...etc.

Rob,
It is correct that this product is a thermal barrier. What's the difference between a barrier and an isulator as long as it reflects heat?

Once cured, if a heat source of any kind is in contact with this product, direct or otherwise, it will not conduct the heat it will reflect it.

I did a "shop test" (no lab coats were utilized)here at my facility. I painted 1/2 the surface of a piece of plywood and then set it down on the screen (painted surface in contact with the screen) on a test table we have for testing different flooring types for conductivity over the screen element. The shop temp is 68 degrees, the board temp was 64 degrees and the table will heat up to 86 degrees. In 2 hours the opposite side of the board that was not coated warmed up to 81 degrees and the side that was coated rose 2 degrees to 66 degrees.

Take from this what you will. I don't think they believe it to be a panacea, just a choice that does what it says it will do.

quote:

What's the difference between a barrier and an isulator as long as it reflects heat?

Well we are talking "radiant" heat. It reflects radiant, not heat in general.

I'm having a hard time understanding why a piece of plywood would only heat up 2*F in a 2 hour period, with or without heat applied to it. I mean, the back side didn't have any paint on it, and the room temp was 68*, and there would have been heat transfer from the unpainted area.