DOW blue board?

[thedoc]

Hi all. New here and love the forum. Im starting my 28x40 shop next week and have been planning for months. The shop will be used to store boat, snowmobiles, and a 1/2 ton pickup and then shop area. Im going with radiant heat and wanted some suggestions on the installation. I live in Iowa so the winter months are pretty cold.

Is the DOW blue board (25psi) 2" thick sufficient enough under a 4-5 inch slab? Or should I try and find 40 psi high load. Im having trouble finding the high load and would have to special order. I can get the 25psi for $21.70 a sheet.
Ive been looking at radiantmadesimple.com and like the ease of a preassemble system. Cost is $2000 for the system and about $176 for a 300' roll of 1/2" pex. I would need 3 rolls. Has anyone had experience with their systems?
What kind of vapor barrier do you typically use under the foam insulation?
The concrete guys want to use rebar on 4' centers so I would need to put 6" wire mesh on top of that to ziptie my pex to. Any suggestions would be greatly appreciated. I will be posting pictures soon to document the build.

 

[thammel]

25 psi stuff is plenty. You'll be amazed but do the calcs for concrete and you'll see that 25psi under your 28 x 40 will be able to support a lot more than you'll ever put on it. The concrete weight is trivial also compared to what the 25psi stuff can support.

Tom

 

[ScaldedDog]

1) Where are you?

2) I used Dow Hi-load 40 for mine, and would do it again. It's $1.21/sf, though, so it's a bit of an investment. My 8000lb Excursion puts 40psi on its contact patches and, though the concrete and rebar greatly dissipates this, I felt it was worth while. 6" of concrete is only 1/2lb/sf, so the concrete weighs nothing.

3) I'd did rebar on 2' centers, and would do it again.

4) I put the mesh on the bottom of the slab, tied the pex to it, then put the rebar on 2" chairs in a 6" slab. I think I'd do this again, though I haven't yet hooked up the heat.

5) I used 6mil vinyl from a box store for a vapor barrier. Works fine.

Mark

 

[tdkkart]

Ive been looking at radiantmadesimple.com and like the ease of a preassemble system. Cost is $2000 for the system and about $176 for a 300' roll of 1/2" pex. I would need 3 rolls. Has anyone had experience with their systems?

What kind of vapor barrier do you typically use under the foam insulation?
The concrete guys want to use rebar on 4' centers so I would need to put 6" wire mesh on top of that to ziptie my pex to. Any suggestions would be greatly appreciated. I will be posting pictures soon to document the build.

The pre-built radiant panels are WAY expensive for what they are, add up the prices of the parts in the system and you'll find that you can do it much cheaper yourself. Their PEX is kinda spendy also, I just bought a 1000' roll for 27.5 cents/ft.

Check out the prices here:
http://www.blueridgecompany.com/

I'm about to do a 24x30 slab, in addition to the 16x30 that I have up and running now. 250psi pink foam board from Menards at about $22/sheet, stapling the PEX directly to the foam which eliminates the wire mesh.

Are you sure you want to us an electric heater?? I can tell you right now it's gonna be expensive to heat 1200sq/ft with electric. If you have gas available I'd go that way before electric.

PM me with your info, it's possible you're just around the corner from me, if so you're more than welcome to come check out my system.

Tom

 

[thedoc]

Thanks for the info guys. I have a pretty good idea of what to do for the floor.
Dan