In floor heat questions.

[conceptmachine]

Thank you for your help in advance.
Prior to the pour is there anything special you need to do to the pex line where the crack joints are going to be cut? Or is that only with expansion joints?

What is normally done at garage doors? Do you create the expansion joint right after the door so that your not heating the snow (outside) there or or is it usually just brought out the 6"? I am having a cement drive as well so wondering if I can just bring the drive portion up to the door.

What distance should I space the 1/2" pex? I'm I'm iowa so winters are bad. Would like a constant 55 deg. R19 walls and r38or so ceiling 10' ceiling.

 

[Randy in Maine]

No need to do anything special for crack cutting. Tell the guy doing it that you have pex in there and he will only cut it about 3/4" deep. I put 6" woven wire on top of the 2" insulation and zip tied the pex to the woven wire grid. My concrete is 6" thick.

Put the tubing 12" on center but anything close to that will be fine. You are essentially heating a rock.

No need for a thermal break between the floor and the driveway. That will help keep the garage doors from freezing to the concrete.

 

[anthony666]

no thermal break is like leaving a window open in the shop, its a direct path for heat to escape .. it's just plain stupid to insulate everywhere else and let the heat escape down your driveway

 

[Randy in Maine]

Put in a thermal break if you wish to, but the heat escaping from the bottom of the garage doors is miniscule and will only keep about a foot of driveway "thawed". Just enough to keep the garage doors from being frozen after a good freezing rain event. We have those freezing rain events here in Maine which is why I did it after the concrete guy suggested it.

The thermal break you do really need though is between the heated floor and the unheated walls if you have some sort of concrete stem walls. I used the same 2" insulation for that. I did mine on the inside of the garage and covered them in pine so that they would not get all torn up.

 

[koditten]

You definately need a thermal break between the heated garage floor and the unheated garage apron(outside concrete). That cold outside slab will **** the heat out of your inside slab.

I poured my inside and outside pads at different times. I placed a 6" tall, 2" foam board between the 2. I capped it with some scrap sheet steel sheered 6" wide. it goes the full widlth of the 2 different pads.

Randy: I think what Tony is intending is not the heat from the room going out under the door, he means the heat flowing out the concrete.

 

[tfinniii]

Do some searching on "radiant heat" and see their advice on spacing from edge and BTU loss and output information in the forum for formula. Basically on the runs by door and other colder spots half your spacing on outer 2 loops and run feed side to those spots first,but I'm unsure of the spacing from edge of slab, one expert recommended 18" from edge.

 

[conceptmachine]

Thanks for the tips guys. I'll figure out something on the doorway. My concrete will be 8" thick.
From reading i need to be 4" depth with the pex. Kinda makes for a pita trying to keep everything off the insulation. What technique would work best using rerod? This is a machine shop so ill have 2, 10,000 lb machines in one area. I wasn't going to run tubing under that area. Should I anyway?

 

[conceptmachine]

You definately need a thermal break between the heated garage floor and the unheated garage apron(outside concrete). That cold outside slab will **** the heat out of your inside slab.

I poured my inside and outside pads at different times. I placed a 6" tall, 2" foam board between the 2. I capped it with some scrap sheet steel sheered 6" wide. it goes the full widlth of the 2 different pads.

Randy: I think what Tony is intending is not the heat from the room going out under the door, he means the heat flowing out the concrete.

Is your 6" cap laying there, or did you bend one or both ends 90. Deg?Was thinking i could do something similar but maybe put in a 1x1 in there when pouring the drive so the one edge has a groove to set in.

Another question
When putting the 2" insulation around the perimeter of the slab in the pole barn, do I try to go around the 6" post or just leave the posts clear of insulation ? Maybe just expansion material there?

 

[jack stand]

Be sure to "daiseychain" all your (pex) loops together and pressurize them (with a gauge) and see that it holds pressure for 24h prior to the pour, then monitor during the pour. The pex is really tough as nails, but this is your last opportunity to make an easy repair.

 

[conceptmachine]

Be sure to "daiseychain" all your (pex) loops together and pressurize them (with a gauge) and see that it holds pressure for 24h prior to the pour, then monitor during the pour. The pex is really tough as nails, but this is your last opportunity to make an easy repair.

Will do!
Can someone tell me the best way to get the pex and rebar off the floor and spacing of rebar for an 8 " thick slab.

 

[BadgerBoilerMN]

You don't tube under machines.

The garage door should have a thermal break in most climates.

The PEX should be raised in slabs over 4 inches thick.

PEX size, length, spacing and pattern are determined by the load and use patterns and sometimes to the heat source.

First a proper heat load analysis to ascertain the right heat source and the required output.

DIY radiant design, always the first mistake.

 

[conceptmachine]

You don't tube under machines.

The garage door should have a thermal break in most climates.

The PEX should be raised in slabs over 4 inches thick.

PEX size, length, spacing and pattern are determined by the load and use patterns and sometimes to the heat source.

First a proper heat load analysis to ascertain the right heat source and the required output.

DIY radiant design, always the first mistake.

Thanks for the input. Downloaded some information for loop length vs pex diameter. I'm gonna go with 7/8 pex, 6 loops at 325' per loop spaced 12". We'll see what I can design around that. Heat source is a 3 phase wall charging unit. The machines take up a good portion of space so i limited the spacing. One thing I was thinking about was polishing the floors. Does.that make a difference in heat loss/gain?

 

[BadgerBoilerMN]

Assuming you mean 3/4" PEX. The industry standard in nominal water pipe size. Barrier pipe.

3/4" is reserved for structures above 10m sq.ft.

You really should get a designer to look at this.

Charger? Is that an electric boiler?

12" O.C. is the layman's, following he manufactures common spacing for slab heat. It may be optimum or 90% overkill depending on the heat load.

 

[conceptmachine]

Assuming you mean 3/4" PEX. The industry standard in nominal water pipe size. Barrier pipe.

3/4" is reserved for structures above 10m sq.ft.

You really should get a designer to look at this.

Charger? Is that an electric boiler?


12" O.C. is the layman's, following he manufactures common spacing for slab heat. It may be optimum or 90% overkill depending on the heat load.

I will here soon, I'm just trying to get some hands on.
is there a reason for not running under machines? I don't bolt them down, they sit on pads.
1/2 pex 8 loops at around 280'/ loop.