does radiant heat work under carpet in basement?

I am thinking about using radiant heat panels (Roth) in an in process finished basement. I have hydronic already in the house with a boiler. But I would be using carpet in the basement...will these types of radiant heat setups work well in a basement with carpeting?

Reply to
beerguzzler50
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I'm thinking that radiant heat *can't* be good for carpet or its backing.

Reply to
Notan

It will work fine. It is best to use as thin a pad as possible and the pad and carpet will lower the efficiency a little, but it will still work fine. Check out some of the folks that sell these systems for more details.

Matt

Reply to
Matt Whiting

Your thinking is incorrect.

Matt

Reply to
Matt Whiting

how will you be attaching the carpet to the floor? much humidity in your basement?

Reply to
dnoyeB

A heated floor becomes uncomfortable to walk or stand on when its surface temperature exceeds 85 degrees F, which means a few degrees higher than that under the carpet. Do you really suppose that 88 deg F will be harmful?

Reply to
Doug Miller

Is there any insulation underneath the slab and, if so, how much? Carpet and under pad are reasonably good insulators and so more of this heat will be re-directed downward and out of your home. It doesn't strike me as a good idea, especially if the slab is uninsulated.

Cheers, Paul

Reply to
Paul M. Eldridge

Yes, the slab should be insulated from the ground no matter what floor covering is selected.

Matt

Reply to
Matt Whiting

I thought it might affect different carpets/backings, differently, but according to Matt, I'm wrong.

I guess Matt knows!

(I'd still check with a carpet person, first.)

Reply to
Notan

Radiant heat is used under carpet frequently. It's just not a problem. 88 degrees won't hurt the carpet. (Would you worry about the carpet being harmed by high temperatures in the summer, if you didn't have air conditioning?)

Reply to
Doug Miller

I wasn't thinking short term effects, but rather, long(er) term.

Apparently, I was wrong!

Reply to
Notan

I researched hydronic radiant heat before building my log house. It certainly is a good idea to do your own research though, and it isn't a good idea to post incorrect information.

Matt

Reply to
Matt Whiting

I am not sure that the foundation was insulated underneath...is there a way to verify? The house was built in 2000 and I don't know the builder. The original owner wouldn't know either. Is there a way to check/verify (without digging under the foundation of course).

Reply to
beerguzzler50

Stand on it barefoot for ten minutes. If it feels pleasantly cool, it's probably insulated. If it feels cold, it's probably not.

Or you could try measuring the temperature of the slab with an IR thermometer. I'd expect it to be noticeably above 60 deg F if it's insulated, but that's just a guess.

Reply to
Doug Miller

There may be, but I'm not aware of any way other than core boring the slab in a non conspicuous location. Locating the builder would be the easiest way. It seems the municipality should have building permit records that might tell who the builder was.

Matt

Reply to
Matt Whiting

That is funny. It would take a pretty well calibrated set of feet to tell the difference in ten minutes for a standard 4" thick slab.

This won't work either as there are too many uncontrolled variables. You are looking for a rate of heat transfer, not an absolute temperature. Depending on the ambience temps in the basement, a slab could be at 60 F whether it is insulated or uninsulated. If you knew of a slab nearby that was insulated and one that wasn't, you might be able to heat a spot on both and watch the cool down rate with an IR camera and compare them to your slab. But that is a lot more work than finding the original building or drilling a 1/2" hole and seeing if you hit foam. A core bore would give you a more accurate sample, but a simple drilled hole would tell you if foam was there, but it would be harder to get the exact thickness.

Matt

Reply to
Matt Whiting

I just realized that there is an open 1ftx1ft hole in the floor for the roughed in shower drain. There is crushed stone in the bottom . I can probably scoop some of it out looking for insulation. How far down is the foam board insulation usually in a foundation? If there is none, should I not conisder radiant floors there? A friend of mine said he had routed out plywood to run pex tubing and that was it for his radiant floor...he hasn't hooked it up yet and it was on his second floor. Is that an option for a basement floor (need to lay plywood).

Reply to
beerguzzler50

The insulation, if it exists, should be directly underneath the concrete slab. And would I use radiant heat without insulation? Sorry, I'm not *that* rich!

Cheers, Paul

Reply to
Paul M. Eldridge

It should immediately under the concrete and above the gravel. If you have to dig through much gravel to find it, then it probably isn't there.

Running the pex within plywood or furring strips covered by plywood is your only option. It is probably still worth it, but certainly won't be as effective as it would be with an insulated slab. If you have enough head room you could always lay insulation on top of the slab and then lay the pex on top of that and over with plywood. However, you are now adding close to 3" to your floor which may be an issue.

Matt

Reply to
Matt Whiting

Just verified that there is no insulation. Would laying 3/4" of foam on top of slab (R4 I think), then plywood with pex be a good approach? Do I need the aluminum in the plywood to make it work? It seems it would be cheaper to route my own plywood and snap the pex in. My other option is to use hydronic baseboard heaters...

Reply to
beerguzzler50

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