Will a second floor stay warm?

[kj_mustang]

I am going to build a 32 x 52 pole building with half the building having a second floor. The entire first floor will have radiant floor heat with 9' ceiling on the two story side. I plan on using 6" of spray foam on the walls and roof. Do you think the second floor area will need to have heat run to it or will having open registers in the second floor down to the first floor allow enough heat to rise to keep it comfortable? I really do not want to run pex into the floor joists of the second floor.

 

[KyleQ]

Ha - I was thinking the same thing... similar building size, similar ceiling height - but a mix of forced air and possibly 1/3 of the floor with in-floor heat.

 

[kj_mustang]

Where are you located? Coldest winter temps?

Should have put that in. Shenandoah Valley of Virginia, usual winter day temperatures around 30-40, nights can go into the single digits but usual is around 20-30.

 

[kj_mustang]

I did a heat loss calculation and have come up with needing about 30,000 btu/hr for the entire structure. Anybody have any opinions on if the second floor will be able to stay around 70 F. if I only heat the slab.

 

[HoosierBuddy]

In southern Indiana, I have a 3 car garage with a bonus room over it.

I installed loops in the joist space, with insulation under the loops to force that heat up, and run the second floor as a second zone with its own thermostat. It seems to work pretty well that way.

I keep the garage at 55 and the upstairs at 72.

Phil

 

[Mike K.]

I built a 28x60 with 12/12 pitch roof. So I ended up with a 15x60 second floor. The rafters have R38 & all walls are R19. No insulation between the floors. Heating just the slab, the second floor is about 5-7 degrees colder than the first floor in the winter.

I may install a small gas heater upstairs if it becomes an issue.

Mike K.
Ohio

 

[egads74]

doing pex on 2nd floor above with heat transfer plates... half way done with the wood...
36 x 44. In cement on 1st floor. Here is a product example... I went above the floor to avoid insulating under in joist to force heat up... http://www.blueridgecompany.com/image/view/527