Radiant Garage Floor Heating Question?

[FrankTheTank88]

I've recently built a 30x40' pole barn and have a few questions. I'm gonna pour a 30x10' section of concrete now so I can use some of the garage and cannot do the whole thing due to letting backfill settle before I pour. I'm toying around the idea of installing the pex-alu-pex tubing for radiant floor heating but a few things I'm not sure of.

1- how do I "zone" the sections of tubing. How long of pipe should each zone be.
2- how thick should the foam insulation be under the concrete
3- I plan on pouring around 5" thick, where should the tubing be in the concrete, bottom, middle, under rebar, over rear
4- can I tie the tubing directly to the rebar or should I attach it to wire mesh and lay it directly over the rebar
5- lastly how far apart should I make my loops. In different terms, how far apart should all the tubing be parallel with one another.

If I should post this in the flooring section let me know as I am doing this work this week and hopefully pouring next week. I looked for this info but can't really get a clear answer on it in this site or on google. And here is a pic because if yall are anything like me, I have to see pics on a post. The area I'm pouring is to the left of the left garage door

 

[Jfresh]

I like to know the answers to these questions as well. Bump.

 

[tfinniii]

These would be a start.
http://radiantdesigninstitute.com/
http://www.garagejournal.com/forum/showthread.php?t=49557

 

[mygarageone]

There's a ton of info on this site , do the search . This subject has been discussed to hell and back

 

[FrankTheTank88]

If you were to read my post, you will see that I did search this site and google, how ever I'm not good with searches. I'm no newby to forums...... not trying to be a ****, but you obviously posted with out even reading my post.

Tfinniii..... thank you I will read over thoes when I get a chance. I'm currently grading out a high spot where I'm going to pour.

 

[rburke65]

Try "radiant heat" or "radiant floor heat". Thee are a years worth of info on this forum. We read your Posts. And I think you want pex tubing with an Oxy. Barrier and not the Pex-Alum-Pex.

 

[FrankTheTank88]

I've been reading over the one link posted above, lots of into in there. I will try that next after I finish 30 more pages, lol.

I thought that is that the aluminum in the pex was for, I will Google that too.

 

[FrankTheTank88]

It looks like 300/400' per loop, 2" foam under the slab, and parallel runs aprox 16" apart. I've seen it attached in many ways, under, over the rebar and attached to wire.

Not concerned about the manifold set up yet, just want to get some tubbing in the concrete.

 

[brewchief]

Keep it at 300' per loop on 1/2" pex.

Use O2 barrier tube, the pex/al/pex should be barrier tube but isn't needed, plenty of reg pex with O2 barrier available.

2" foam, typically high density.

12" centers for 1/2" tube layout is the standard for a basic system with no formal design.

Use electrical conduit sweep 90s where it comes out of the concrete for protection.

Proper edge insulation should not be overlooked.

 

[FrankTheTank88]

My first pour is gonna be 300 Sq ft, so that loop will be just over 200'. Should I bring that loop back up and continue it into my next pour a year from now? Or just install a flow valve on that loop.

Edge insulation as on the sides of the slab correct?

 

[rburke65]

Your loops should begin and end at the manifold location. Rule of thumb.....i believe is a linear foot per square foot, so if ya have 300 Sq. Ft. then 300' of 1/2" pex. That way you can on troll that zone separately. When you run pex for the other area, all those loops should begin and end at the same manifold area.

 

[FrankTheTank88]

I do understand they have to continue and end in the same place, was just wondering if my zone was gonna be too small but it sounds like it will be right on par. Thank you for all your help

 

[homebuilt burner]

I just poured yesterday on my 14' x 26' which is similar in size to your 10' x 30'. The recommendations I received was for 2 runs @ 200' long I split the building down the middle and put a loop on both sides. The spacing gets closer than I wanted but I would rather have too many btu's available that not enough. There is a ton of info on the net about floor heat and this forum as well, if you read up you will get a general idea on tube layout and as long as you follow some general rules you shouldn't get in to much trouble. rburke and brewchief have mentined some good basics. I used some 1" electric conduit elbows welded together to run my tube out of the slab. I also made a 10' pex run that dead ends in the slab if I decide to run a temps sensor in the floor.

 

[BadgerBoilerMN]

First, all the information is dependent on your location and heat load.

Steer clear of the "Institute" unless you are looking for designs to avoid.

Generally, 250' regular oxygen barrier PEX, 12" O.C. stapled to 2" of XPS. PAP is over-kill, as is a 5" slab.

Slab sensors are generally of little use to the novice and ambient thermostat on an inside wall will do. Ecobee if you want to get fancy or don't want anti-freeze.

You should not have to wait for settling, you should use a compactor.

Re-bar is not needed and wire can go over the PEX if you want crack control.

Edge insulation, yes.

Size the boiler using an ACCA Manual 'J' heat load software.

 

[FrankTheTank88]

Day late and a dollar short on the compactor, I've ran a jumping jack over the whole thing for hours but I will wait for settling now (and cannot afford the whole pour right now)

I've just about completed the prep for the pour, I will upload a few pics tomorrow.

Thanks for everyone's help.