floor on sleepers above a radiant slab

Carp

I have a homeowner that wants me to install a radiant slab zone for him. Then he wants to add sleepers on top of the radiant slab and install hardwood. May I get some feed back to support that this will not work properly?

Carp

OR......................

Tell me why you think this will work. I am interested.

Alan (California Radiant) Forbes

Sleepers

If you install sleepers on top of a radiant slab, there will be an air space between the slab and the hardwood.  Air is an insulator and will restrict the upward movement of heat.



A better way is to install the sleepers flush with the top of the concrete so that the hardwood touches the concrete. 



These pictures are from a job we did in 2003 and there may have been some thin material installed between the concrete and hardwood to avoid direct contact.

NRT_Rob

air space bad

back of the envelope math I've done on this before indicates a fairly restricted output for this kind of system.



If he does this, additional concrete should be installed between sleepers.



or, if nailed wood is a must, normally it is nailed to a floating layer of plywood. This also reduces heat transfer, but less than the airspace would, and you can plan for it with the tubing install (tighter on center, higher water temps).

Jean-David Beyer

Why does the customer want to tell you how do do the job?

I am not a contractor, but it seems unfortunate that the customer wishes to specify both the requirements and the implementation of a system. The customer should specify the requirements, and leave it to the designer to come up with a design to meet those requirements; at least, ideally. I suppose you cannot expect better from the average homeowner, but in a case like this, should you not try to educate him? If he wants radiant heat and hardwood floors, he can have that if the flooring contractor knows what he is doing. But putting an air space (the sleepers) between the radiant and the hardwood floor is likely to be quite a heat loser. Is he trying to protect the tubes from the nails?

Carp

Thank You!!!!!!

Thank you for all of the input! I am basically tring to prove my point! I will NOT do an job this way, however I want the homeowner to realize just what JDB has said!



Thanks for your help in this matter!



Carp