Bathroom Heat

Andrew_8

I am replacing the floors in 3 bathrooms (2 back to back, the third above one of the back to back ones), and want to replace the radiators with radiant heat. One of the back to back baths and the third bath had radiators, while the other bath was too small to have heat. I had originally planned on installing electric mat heating, although the third bath will probably have a wood floor, which would make this method problematic. I then decided to install hydronic radiant heat, because a) I already have radiators and therefore a boiler; 2) I plan on installing radiant heat in the first floor next summer, so I will require some of the fixed cost hardware anyways; III) floor height in the back to back baths will already be at least 1/2" higher than the surrounding flooring, and mat heating would raise it even more.

I think I can do all 3 baths on one loop of 1/2" PEX, although that would require one thermostat controlling a zone covering two floors. The back to back baths have to have the tubing placed from above, before the subfloor. One plumber suggested something like chickenwire loose across the joists, the tubing tied to that, and then the subfloor put down against the tubing, with the chicken wire holding it to the subfloor. Insulation below, of course. And for the third bath, I had planned on a stapleup application attaching the tubing directly to the subfloor.

Any opinions on this installation plan, electric vs. hydronic, proclamations that I'm crazy to even contemplate such a thing.

Thanks

Andrew_8

Bathroom Heat

I am replacing the floors in 3 bathrooms (2 back to back, the third above one of the back to back ones), and want to replace the radiators with radiant heat. One of the back to back baths and the third bath had radiators, while the other bath was too small to have heat. I had originally planned on installing electric mat heating, although the third bath will probably have a wood floor, which would make this method problematic. I then decided to install hydronic radiant heat, because a) I already have radiators and therefore a boiler; 2) I plan on installing radiant heat in the first floor next summer, so I will require some of the fixed cost hardware anyways; III) floor height in the back to back baths will already be at least 1/2" higher than the surrounding flooring, and mat heating would raise it even more.

I think I can do all 3 baths on one loop of 1/2" PEX, although that would require one thermostat controlling a zone covering two floors. The back to back baths have to have the tubing placed from above, before the subfloor. One plumber suggested something like chickenwire loose across the joists, the tubing tied to that, and then the subfloor put down against the tubing, with the chicken wire holding it to the subfloor. Insulation below, of course. And for the third bath, I had planned on a stapleup application attaching the tubing directly to the subfloor.

Any opinions on this installation plan, electric vs. hydronic, proclamations that I'm crazy to even contemplate such a thing.

Thanks

hot_rod

Leave the chicken wire in the coop!

Look into some of the above floor products. Wirsbo Quik Trak is one popular one. a much more sane method than dangeling tube on wire in the joist bay

I would suggest a seperate loop in each bathroom for "fine tuning" It could still be one zone with individual loops with balance valves.

A wood floor in bathroom 3? Really! Doesn't sound like a good fit to me. Too much humidity swing and potential water spill. Possibly one of the "engineered" products that Wilsonart offers that is "wood like" but made for bathroom floor applications.

Consider finding a radiant savy contractor to assure your plan is workable with the current radiator system.

They aren't steam, are they

hot rod

Andrew_8

Hot water. And I hadn't really considered something like Quik Trak due to the increase in subfloor floor height, plus cost. Having seperate loops in the same zone makes sense, though, allowing me to finetune heat output. Two of the bathrooms are on the corner of the house, while the master bath just has one, 5', exterior wall, and a ceiling partially open to dead attic space. We have a Burnham gas boiler, about 15 years old. Would I have to worry about it if only the radiant heat is on, and the boiler zone is off? I'm thinking it might heat the water up too quickly for the small zone, and then short cycle.

As far as the wood floor in the 3rd bath, yes, I know that it could lead to problems down the road. But we like the look, and with new wood finishes, it shouldn't be too bad. We are refinishing the clawfoot tub that is in there, and putting beadboard wainscotting around the room.

Art Pittaway

Sleepers might still work

worked on a second floor bath several years ago in a Victorian where the ceiling below could not be disturbed. The bath floor had to be pulled up exposing the ceiling, fiberglass insulation with foil up was laid on the ceiling, then furing strips (1x3) were screwed to the inside of each joist at a proper distance to lay in a 1/2" plywood board. This supported the sleeper and tube so they were just level with the top of the joists. The subfloor is then replaced over the floor joist and in contact with the tubes. You could even use alum. plates with this method. The floor was tile. A bath/hot tub at one end gave us access to all bays without drilling holes in the joists. The house boiler never went over 150 so we hooked up a primary/secondary loop with a B&G NRF pump and a thermostat, nice smooth even heat. A year later I stopped to see how the job was and it took over a half hour to escape the homeowner as he showed off how great the new bath was.