Where can i find info on infloor heating question

[JBAUTO]

Hey guys im going to be buying a house finaly and will be building a 30x32 wide garage.

Im going to be doing a 4 ft foundation wall and was wondering what the best process would be to do .

Once walls are up the floor would be lowered 1.5-2ft and would do a layer of crushed stone then either earth or sand to go over and smooth out the floor. Then i would do a layer of vapor barrier then one layer of 1" foam insulation then mesh rebar spaced up 1" with PEX piping affixed to the wire mesh then i would do a 5" poor of concrete.

Is this the correct process for doing infloor heating or can anyone help me out or guide me in the right direction


Josh

 

[jklingel]

JB: See two posts above yours, diychatroom.com, PEX manufacturer's web site, etc. Your plan sounds about "normal". Questions: Got good footers on undisturbed substrate? Familiar w/ compacting gravel? 2' of gravel sounds like a lot; is that required for your area/soil? Location? (may need more than 1" of XPS under the slab). PEX can go above or below wire/rebar, each with different results/benefits. We just discussed a lot of this above. j

 

[JBAUTO]

Thanks JK Im new to this stuff. The guys at work said im going to spend a arm on leg on crushed stone. XPS is what exactly? Foam ?

Think i read about having the pex below and above were the slab would heat up faster above and slower below but would hold heat better.

 

[Burl]

My garage build is exactly the same size as yours, though mine has a 12' ceiling. I used about 6" of stone, just enough for support and to level out the floor as best as possible, no more thickness is needed (and my concrete was 8" thickness). I wouldn't think that you would need sand or dirt to level, just get it as close as possible with the stone. You're correct from there, plastic barrier, etc. I used mesh insted of rebar (and you could too) and zip-tied my pex tubing to the mesh. I used 1000' of pex, 2 spirals per half of floor (1 inside of the other, in case one should happen to fail,etc.), and I did the floor in 2 pours. I'm using a NG hot water tank for heating Dowtherm antifreeze, I kept the garage at 60 deg. all winter, and my gas budget went DOWN $25/month this winter.

 

[jklingel]

Thanks JK Im new to this stuff. The guys at work said im going to spend a arm on leg on crushed stone. XPS is what exactly? Foam ?
Think i read about having the pex below and above were the slab would heat up faster above and slower below but would hold heat better.

XPS is extruded polystyrene. Blue foam, pink board, etc. It is more dense than EPS, or expanded poly. That stuff is not waterproof; XPS is. Be sure to get 40 psi stuff, or maybe 60; have to ask an engineer on that one, depending on what you are driving on it. Myself, I'd not put visqueen (or whatever you'll use for a vapor barrier/retarder) over crushed rock; too sharp, and will perforate the barrier, I would think; never worked w/ it. Why do you need crushed stone instead of gravel? It IS spendy. Too, I don't know how well it compacts. I am only familiar w/ gravel and fines, that compact nicely. The flatter the substrate, the more accurate your calcs on volume of needed concrete will be. If you keep the garage at a constant temp, I don't think it matters stink if the PEX is above or below the rebar/mesh; if it is above, think twice before you anchor anything to the floor by penetrating the concrete. If anything, over-kill wire/rebar; it'll be there for 100 yrs. Good luck. j