Radiant Heat Lines

One of the big jobs this year was laying PEX radiant heat lines on top of the styrofoam base in the basement. The masons had laid the styrofoam on top of gravel and had laid the iron grid on top of the styrofoam. My job was to lay out and attach the PEX. This involves first figuring out the layout. You want heat lines 6" apart near any wall and no less than 1' apart elsewhere. In addition, you want the line to coil in and then out in a big curlique so that the heat is disseminated equally since the water is hotter coming in than leaving. The lines can't cross each other and there were various obstacles (poles and plumbing). I took to first laying out the design on graph paper (after a lot of erasures) and then installing the PEX with zip ties. In some rooms I marked my route with spray paint. In this picture you can see me installing the PEX wearing a "clean" shirt with soap residue on it.

The PEX comes in 300' and 1000' coils (which are heavy). To keep the coils from getting twisted Markus created this spindle. It still required me to horse the coils around to unwind them. In this photo you can see various tricks to the installation such as S curves and the plumbing I had to work around.

The finished layout in one half of the basement. This is the shop with the root cellar in the back. The bathroom/laundry room is on the left (not in the photo) and the garage and equipment room (same depth as this photo) are on the right. It took me six days of pretty constant work to finish this.

The last thing was to attach both the source and return pipes to the wall and the valves (which I did with Markus). The masons then came back and raised the whole thing on 2" bricks in preparation for pouring the concrete. Markus has to pressure test the system for 24 hours and get it inspected before the cement can be poured. It turns out that I had not cut off the zip ties close enough to the metal grid so that they would be completely burried in the cement, so after the whole thing had been raised I had to go around on tip toe (the squares are 6" on a side) and cut off all the tails.