Staple up radiant floor and ceiling in joist bay

Riley12

Im trying to heat two zones one on main floor and basement. House will be insulated to standard. Forgive the rough sketch im hoping to get enough separation from the two zones to have a radiant floor in main level and a radiant ceiling in the basement due to already low headroom. Would this design help the two zones run independent or are the just to close together and cause to many issues? Thank You.

warmAK

I have never tried a heated ceiling, I have seen hydronic ceiling panels but they sit on bottom side of drywall and in my opinion it’s hard to get the heat to fall.  In that scenario you would just have a second zone controlled I. The basement pumping heat to your upstairs.  Your options would be gypcrete(in floor heat) loose 1-1/2 of head room and cost a bit.  Or baseboard or panel radiators. 

Ironman

It can be done, but understand that a radiant ceiling requires much higher water temps than a floor. You would have to create two separate water temperature zones.

heathead

I have done the exact system you describe. My basement is below grade, at the time also did spray foam to walls. Some would say it was a waste of money to use closed foam for walls below grade, but did the rim joists also in that. Ironman is right that ceiling should be running a higher temp zone than the floor. I am still running the same temp in mine and it is working better than it should with one temp. I may leave it at all the one temp, it's not as far off as I was expecting.

KC_Jones

warmAK said:

I have never tried a heated ceiling, I have seen hydronic ceiling panels but they sit on bottom side of drywall and in my opinion it’s hard to get the heat to fall.  In that scenario you would just have a second zone controlled I. The basement pumping heat to your upstairs.  Your options would be gypcrete(in floor heat) loose 1-1/2 of head room and cost a bit.  Or baseboard or panel radiators. 

Heat moves to cold, period. This whole "heat rises" is a myth. Hot fluids rise, radiant isn't heating by convection (heating a fluid, including air) it's heating by radiation, which moves to cold and has no regard for direction.

Radiant ceilings have been around for decades, this isn't a new concept.

hot_rod

Ideally you would want to know the supply temperature for the floor vs the ceiling.
3/4 subfloor with 3/4 hardwood = R 1.8
1/2 sheetrock around .8
So depending on the heatload of each space, the upper floor may need higher SWT.
120F is about as warm as you want against sheetrock. The upper level could require 140F if it sees high loads.

You could play around with tube spacing to get the temperatures for up and down close to one another.

If the upper and lower rooms will be kept at the same temperature, that makes the math easier also.

So if you had a heatload for all the spaces, and a design indicating required SWT you could better answer the question. Generally speaking basements are a lower, sometimes much lower heat load space. And in some cases radiant floors alone cannot cover the loads in some rooms even with floors running 82° surface temperatures.

The R30 between upper and lower will help limit unwanted heat transfer between the floor and ceiling systems. If anything I would wonder that the basement may over-heat a bit at high upstairs load conditions?

Alan (California Radiant) Forbes

The upper level could require 140F if it sees high loads.

Hot Rod: With quality plates (Radiant Engineering, et al), my experience is to keep water temps below 120F for hardwood. My floors reacted at 130F.

hot_rod

Alan (California Radiant) Forbes said:

The upper level could require 140F if it sees high loads.

Hot Rod: With quality plates (Radiant Engineering, et al), my experience is to keep water temps below 120F for hardwood. My floors reacted at 130F.

I agree the wood manufacturers recommendation should be followed regardless of the plate or tube charts. And common sense and actual experience

I agree also the goal should be 120 or below 

Uponor shows 165 as the high number for their plates

Alan (California Radiant) Forbes

hot_rod

Alan (California Radiant) Forbes said:

The bottom table shows double row plates 8" OC at the same temperature max. I think they are refering to this thin gauge version?

Alan (California Radiant) Forbes

I see now - thanks. It's interesting that you only get about 20% more heat with plates.

Part of the reason I like Ultra-Fin is that you can run higher water temps. without damaging the floor.

hot_rod

Ultrafin look to super charge the suspended, or dangled tube method that Wirsbo promoted heavily in the 1990. As an answer to the rubber tube staple up competition.
The expansion rate of Pex prevented it from being a direct staple up method. Although many tried😳

At a recent Uponor training they still suggest not stapling one side of the thin gauge plates so they don’t oil can. Make the ticking sound as they try to expand and contract. They do offer the extruded plates as well as a panel similar to the Roth, however.

Alan (California Radiant) Forbes

I installed the thick ThermoFin C in my house in 2007 and we stapled both sides. In the morning, the ticking sound is comforting. I (almost) always use that as a selling point.