Radiant Heated Shower Walls

hr

you did a lot of work to install the tube like that. I use extruded plates and fasten them to the studs vertically. Looks like you did a first class job.

I would think the 6 mill could with stand the low temperature you will be running to that system, probably less than 100 degrees f.

Seems it is the UV that breaks that 6 mil down, not really the warm temperatures. Guess you could go with the black UV resistent color?

They do make that shower membrane in several thickness's. I can't imagine a 30 mil would pose much problem if you really want to go to that expense.

hot rod

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Dave Meers

Radiant Heated Shower Walls

I have been building a log home for the past five years and installed staple up radiant floor heat with thin plates. My radiant system was designed by Northeast Radiant Technology (Rob Brown). I had some tubing and plates left over and after seeing some radiant heated shower walls on this site, I decided to include it in my project. See picture posted below. It is a 6 foot X 6 foot neo- angle double shower with a heated corner seat (for my wife - not me).

Sorry for the long post. Now to my question. I routed out grooves in the horizontally mounted 2 X 8's and stapled the plates with tubing to them. Now I am ready to install the Hardibacker board and understand that I need a vapor barrier between the plates and the backer board. What should I use? I think 6 mil plastic will deteriorate with the heat and PVC shower floor membrane will be too thick and could also crack over time. I wonder if aluminum sheet would work - the kind you use to wrap window and door trim? I could overlap the edges so and water would stay between the aluminum and the backer board.

What would the pro's use? Thanks!

Bob_41

Membrane

I'd use Redguard once you've completed the durock and taped the seems and joints with thinset. It's both a vapor barrier and waterproofing membrane that can either be rolled or trowled onto the backerboard. No need for additioanl plastic. It's also approved as a liner to replace the PVC liner. I can't imagine the heat cuasing problems and deterioration with the liner, what temp do you envision using? If you don't care for using the pvc liners then there is a solid one piece custom liner also available ... its called the One-liner. I have no experience with the product.

http://www.dixsystems.com/

Bob

Josh_10

MMMMM looks comfy!

Weezbo

that looks good. it is inspirational *~/:)

6 mil should work.your hrv supply and bathroom fan will keep things dialed in...not to worry.

after looking at your lash up i immediately felt like going down to the shower room we installed at the baseball stadium 24 years ago, ripping all the wallls out and spinning in some radiant walls Keep up the good work

Unknown

Hi David,

Should have called first, my friend. Your system is relatively high temperature. I would not want to run those walls at the prevailing water temperature you've got in the rest of the system.. it'll be *hot*. You need to limit the temps in those walls, first and foremost. This means at least a pump w/adjustable bypass, or a 3-way thermostatic valve and a pump.

Secondly, in no case should you put aluminum over this assembly. Metal on metal, plus temperature changes, equals noise. No good.

These don't look like outside walls, why would you need a vapor barrier? are you not insulating beyond the shower walls?

Dave Meers

Hey Rob, maybe it's not too late. The walls aren't covered yet and the supply and return for this loop are still hanging in the basement. At least I asked the Pros here before going too far.

The makers of Hardibacker board recommend a vapor barrier behind their product when used for shower walls. Apparently, any moisture that gets through the tile grout will be absorbed by the backer board and then get behind it leading to mold and other good things. Okay, aluminum is out - 6 mil plastic is in.

Regarding the temperature control, couldn't I keep this simple by making it a sub-loop of the master bedroom/ bath floor with a control valve and thermostat? Or possibly feeding it from the cooler return manifold water instead of from the supply? If not, I guess one more pump won't hurt........

Unknown

Once you put in some kind of control/bypass/thermostatic valve, you really want to be pulling from it, not pushing through it. unless I misunderstand what you mean.

f the builder

barrier definitely called for why not use ice and water guard self sealing around fasteners

Dave Meers

Ice Guard would certainly protect against the moisture but from what I've read here and on the RPA website, the heat will cause it to off-gas and make my whole house smell like burning tar paper.

My flooring contractor started out installing tar paper under the hardwood after I had told them to use resin paper or nothing at all. Of course, they also didn't mark the tubing or joist centers and hit the tubing with the very first nail driven. That was the end of their work on my log project........Now I'm installing the hardwood myself.

Alex Giacomuzzi

How About Some Reverse Engineering....

Since you already know what circuit you want to connect this tubing up to, you already know the temperature of that loop ---- sort of anyway. In either case --- you have the radiant water temp and the flooring area resistance and design....

So ---- rather than install another separately pumped and controlled circuit, how about un-installing what you have pictured above (which does look very nice by the way), add a sheet of 3/4" plywood to the walls (shower side)(which from a design perspective would be your subfloor in your normal flooring application) then install the tubes and aluminum plates vertically on the backside of the plywood.

Now --- you have added some "R" value to the heat transmission into the shower. If you need more --- space them off the plywood and insulate behind them. Now add your poly or ice and water or what ever plus the Cement Board on the shower face and you are in business...

After seeing your nice work, I almost hate to suggest this, but it does solve the temperature problem... with the minimal amount of hardware to change....

Good Luck... Alex

Jamie_5

go simple?

Why not simply connect the very nicely installed loop to the domestic hot water supply for the shower? Probably close to the right water temperature, and you only heat the walls when you are showering, which is when I assume you want the walls warm. No pumps, no controls, no tearing out what you have, and stone simple.

Dave Meers

Interesting idea and it would be pretty simple to connect it to the hot side of the two shower valves. I was hoping the shower walls and floor would be warm before I get in and also help dry the shower walls afterwards. I doubt w if my 5 minute shower in the AM would provide enough heat fast enough. Maybe I could get my wife to shower first........to get it toasty before I get in.

I am planning to install balancing valves on all four loops of the master bedroom/ bath floor zone plus one on the shower wall loop to adjust the temperatures. If that doesn't work, I may try a thermostatic mixing valve as previously suggested. Thanks!

Rodney Summers

What temperature is going to be running through this? If it's around 100F is that going to cause problems as NRTBob mentions?