We are building an all concrete home using ICF and Hambro concrete bar joist floor system. We hope to also use Geo thermal heating. The home is located on a lake and will see most visitor trafic during the Summer. But during the holiday season, we could have all the kids home for X-mass. We like the radiant for all the obvious reasons but also being able to Zone control vacant rooms out of the heating picture. We have poured the basement walls and are getting ready for the basement slab. The basement will have a spare bd rm and a rec rm. But mostly just a basement and will only be used as over flow. I have debated even if we need to tie the basement heating in the main system.  So we have planned to get the radiant tubes in the bacement area that could be used.

1 Zoning. With the need for heated spacing chaging during visits, heavy zone control makes sence. Also, balencing room loads would be less critical. For example; If a home had one thermastat, you could have hot and or cold rooms based on poor calculations. With thermastats in each room this issue wouldn't be as big a risk?

2 Typical diameter, 1/2, 5/8 or 3/4? Big box stores sell 1/2" for about .20/ft
   Does the use of Geo vs. Boiler effect the pipe size?

3 Typical spacing?, 12" looks common

4 Pex type, Oxegen barrior? From what I read its for iron pipe/components. Does new equipment, geo or boiler types, use "iron" products?

5 Pex type, A,B and C. Big price difference for points 4 & 5! I understand there are diff methods for cross linking
   Pex brand? Wirsbo appears to be the most expensive. I don't want inferior pipe but I also don't want to waist money, we'll need 5000' for the whole project.

6 Slab on grade; If you have a run going through an unheated area, should you place the tube fully belowe the slab and well insulate? I just as well not have all the supply lines super heating a section of the basement near the mechanical room. I thought I could dig a trench in the gravel fill belowe the slab and build a foam conduit. Then raising into the slab where the heating need starts once inside the room? The distance is 25'.

7 The Wirsbo install guide shows the renforcement mesh placed down over the foam and the tubes attached on top. They clearly state the mesh will not be for structure! Looks like a waist of material. I would like to have my mesh as structure. So if I can, I will run the tubes on top of the foam using staples to secure the tubes in place. After, placing the wire mesh on top. This would place the wire mesh in the bottom inch of the slab, right where it needs to be for strength. Any issue with this?

8 Long runs through suspended floor system. Use larger dia pipe well insulated and use a manafold near the load?

Sorry for so many questions..

Patrick T.

Looping a system as if it were zoned can be a good "bet hedger" without having to install all kinds of zones up front. Then, if anything were wrong, zones could be added later.

Pipe size shouldn't be any larger than 1/2" for the loops in the vast majority of systems. Pipe size, loop length, tubing spacing, flow rates, all this stuff is dictated by the heat load.

Oxygen barrier is very highly recommended for any system. It protects a lot of potential components of the system including glycol, should that be necessary now or in the future.

If the mesh is present, go ahead and tie the tubing to it. Wirsbo is saying the mesh is not for structure because it isn't; rebar is for structure. Mesh just holds cracked pieces together a bit better.

not sure what you're asking with number 8.

We are an ICF contractor in the midwest.  We put radiant in all the custom homes and light commercial buildings we build. We use a product called Crete-Heat for our installs. You can check them out @ link Saves you labor now and energy forever.