Hardwood flooring over in joist heating advice...

[RobAHali]

Hello, I'm building a house and trying to descide on flooring. The heating system on the 2 floors will the "in joist" floor heating. We really want to use Hardwood floors. We have been told many different stories about using Hardwood VS using Engineered Hardwood over the floors. What I've read is that if you pick the right wood (Americian cherry) then you can do a regular Nail-down installation of the floor (being careful of the pipes of course).

What i'm wondering is if any here has any advice on the subject. Does anyone have any experiences good or bad installing real hardwood over injoist heating?

Thanks in advance, Rob

[Bob Pietrangelo]

Sqeaky and not that great of transfer of heat, not like tile . If you are willing to change the flooring you, it has to be a floating connection not a nailed down connection. It is not unbearable, but it is a little creepy sometimes! If this is a new construction why in the world would you go with an under the floor board rather than above. Alot better heat transfer.

[tbasc]

NOFMA web site has good tip sheets. Flooring Manufacurers ought to know what works. TB

[RobAHali]

thanks for the response.

It was the builders suggestion to do the "in joist" heating. The in joist heating is not done at this time. The building is a shell and has the floors built. In the basement there is a concret slab with the pipes already in for th infloor heating. The other two floors are just plywood with no heating pipes installed yet. The builder said he was going to do in joist on those floors.

Will engineered Hardwood give me better tranfer then hardwood? We will have tile down in kitchen and hallway, but we wanted to do the dinning and main room in hardwood. We do not want laminite, we are sure about that.

Thanks again for the advince.

Rob

[Bob Pietrangelo]

It sounds like infloor was thought of after framing was completed. Otherwise he would have just added a second 2x4 at the bottom of the wall. That is what i have always done. Then w/a gyp pour transfer is great.

Any way. Your radiant design has to take into account the floor coverings for each room prior to determining tube size and piping distances.

Doing it under subloor is a real pain in the ass for the installers, above floor pour and mesh in rebar is alot easier. You have to install your tubing the best way possible under floor. I like to put my loops through the floor joists but that is really hard on big installs, they are probably only going to 150' of tubing at a time. Some guys just let it hang below the joists at each end.

The tubing should be stapled or nailed to the subfloor inder radiant panels. Then the cavity below the tubing should be insulated leaving about a 1" gap and then as much Rvalue as possible. Rigid foam works good too.

You can have carpet, tile, or wood. Wood should not be nailed down

[HeatMan]

As long as the surface temp does not get above 85°, you should be okay.

Using joist plates is the most efficient way to transfer the heat to the flooring, but the nails from the hardwood can negate the contact with the subfloor.