infloor heat depth

[2011laramie]

Im pretty sure there was an article posted a while ago that said it didn't really make a difference if the radiant heat pex tubing was stapled to the Styrofoam and at the bottom of the slab vs tied to the rebar and within the top 2" of the slab.

Does that pex stapled at the bottom of the slab really hurt performance and efficiency on a 4-5" slab?

 

[Rookie2]

I installed Wirsbo years ago ,now Uponor Wirsbo. It is on the wire mesh under 5" of concrete. Wirsbo had several books on the installation do's and don'ts if you can call the new company they could help. I think it would only delay the process for several hours at start up.

I did learn to fire up my system a few days before the cold was about to hit us.

 

[theoldwizard1]

Im pretty sure there was an article posted a while ago that said it didn't really make a difference

GJ Link

 

[koditten]

Mine is stapled to the insulation. An inch or so isn't going to make much of a difference. Just takes longer during start up. Once that slab is up to temp, it matters little.

 

[BlueBomber]

I tied the PEX to the wire mesh, but then elevated the mesh with busted cinder block pieces so that it would be suspended inside the concrete rather than sitting on the bottom. This was as much about getting structural benefit from the mesh than it was about where the heat transfer takes place.

 

[kj_mustang]

I tied the PEX to the wire mesh, but then elevated the mesh with busted cinder block pieces so that it would be suspended inside the concrete rather than sitting on the bottom. This was as much about getting structural benefit from the mesh than it was about where the heat transfer takes place.

I did it the same way and for the same reasons.

 

[rburke65]

The general thought is that it will not matter. Good luck!

 

[finn]

I bought a building with PEX embedded in the floor. Best I can tell, the building is about 10 or 12 years old.

In one short area, about 8" of PEX is exposed. It looks like the tubing floated during the pour and a piece of concrete eventually fatigued and broke off.

There are also many hairline cracks above the tubes in several places. A thermal imaging camera shot confirms that the tubes are directly below these cracks.

The system functions well, so I consider these cracks to be more of a visual nuisance than a functional problem at this point, but if I ever had a slab poured, I'd shoot for tube depth in the lower, or maybe second quadrant of the pour.