After the vapor barrier, horizontal and vertical insulation went in, Tim and Jim from Precision came back to put in the rebar on the pad area.
Once that was in place, Kyle and I could start laying the pex tubing for the radiant heating. And like everything else, the first section took a few "redos" but after that it was pretty smooth sailing.
It is not terribly difficult to install. We had a radiant expert design the layout and the lengths of each run. Of course when we got the design we realized it was all wrong. He had designed for two manifolds, which we have one. He had the tubing in the containers running through the container walls, which can't happen. So we need to do a little alteration on the fly while keeping the lengths somewhat the same and the runs even.
It worked out pretty well and it is great because the tubing is marked each foot with the length so you can judge where you are in the run and how much you can go to the end.
The radiant in the containers were screwed directly to the wooden floor using little snaps that hold the tubing and have holes on the side for screws.
The tubing on the slab area got zip tied straight to the rebar and was a little trickier because you wanted to follow the rebar as much as possible to stabilize the loops but the spacing didn't always allow for that.
There are 10 runs total with 4 heating zones. This means that there are 10 lengths of tubing ranging from 220' to 270' in length and we will have 4 separately controlled zones for adjusting the heat. There are 4 runs through the slab area and 3 runs through the containers and then 3 more runs upstairs through the containers. It is great because you don't have to run heat where you don't need it. So we didn't run tubing under the kitchen cabinets or in the pantry, to be able to control where you put heat and where you don't is fantastic. On the flip side we tightened up the loops in the living area as that is where we would probably spend most of our awake time and it has the highest ceiling so we wanted to concentrate more heat in that region.
Kyle got the last of the tubing connected to the manifold at 2:30am on Friday morning and pressurized it on Friday morning (at a normal hour) in preparation for the building inspection. Friday we had both the building inspector and the bank inspection, hectic day on little sleep. All went well and we got the go ahead to pour the slab the next day so it was all systems go to get the guys lined up and the concrete trucks ready.
You learn a lot as you go like when the manifold was losing 8psi in the first few minutes of pressurizing the tubes but then holding steady. Kyle was pulling his hair out to figure why the pressure gauge constantly dropped upon adding pressure. Then the sun went down and the pressure went back up, huh, that is reverse of what should happen with heating and cooling until we figured it out. The sun was softening the tubing and thus expanding and reducing the pressure and then when it cooled down and the tubing went more rigid the pressure would rise. Go figure.....and yes, figuring this out was the highlight of our day. We need to get out more.