From the top down

big willy

I want to use heat transfer plates in a new construction situation. Is there a company that makes plates that can be nailed to the top of a 16" on center joist. I have used the Zurn plates that are 5" wide from the bottom in a retrofit application. I could use these here but that means one side of the plate is hanging. I know that direct contact with the subfloor is a large part of what makes them work better than using wirsbo pex clips that hang the pipe 3X4 below the subfloor. A 16" wide thin sheetmetal plate thats stamped for two tubes would be ideal.

Mike T., Swampeast MO

Do you mean to attach the plates to the sides of the joists? If so, that's not the best way--you really want them attached to the floor/wall/ceiling itself.

With the nice, heavy extruded aluminum plates from Thermofin and others it's easy to install two runs per standard (14 1/2" clear) joist bay.

The problem with the thin "sheet metal" plates is that it's exremely difficult to keep them in intimate contact with the surface to which they're attached. To keep heat transfer via conduction as high as possible (GREATLY desirable) you want the plate to be in the most intimate possible contact with the surface--easy with nice extruded plates, but far from easy with "sheet metal".

Hvacman

He wants to...

Span the tops of the joists with the plates... a 16 wide plate with joints centered lengthwise on the joists? This sure would insure the plate stayed tight to underside of floor!

ALH_4

Yes

Edit: Are you running the tube parallel to the joists or perpendicular to the joists?

I have seen it done perpendicular to the joists with Thermofin-U extruded plates, and I understand that it was a balancing act as Jed mentioned. It was not the easiest installation method. I would also be concerned about the effect of construction adhesive on the tube.

Why not install it above the subfloor?

Jed_2

Visions

Wow. I have visions of a tube & plate sub-floor installation "from above" before the sub-floor is applied. Can you say "balance beam gymnast"? The "16" O/C plates stapled to spacing pattern, then the loop design layed in per loop design. All the while being very mindfull of "future" partition plan, kitchen cabinets, islands, etc.
Oh! And the nails!!!

I'm not an installer, but that still scares me.

Jed