Cool looking project you have going there. I finally got mine poured......and yeah, I said poured, after a year and a half of back breaking work getting to that point.
I used 3/8 rebar on mine and blocked it off to where I had 2' square blocks all over the floor. I had one perimeter run that was 6" from the sides then another 6" from that one all the way around then I jumped to the 2' patern the rest of the way. My building is on piers and I drilled holes in those and inserted short pieces of 1/2" bar in those to tie the slab to the piers. I also doubled the rebar up at the big entrance door and laid down a little less than 1' squares in the apron.
I used 1" foam around the perimeter and 1/2" in the center which should be fine for the winters we have around here. Also I put 1" pink board on the sides down to 12 to 18". I used the plastic rebar chairs and I sat those right onto the insulation panels and tied my pex to the rebar. I had it graded fairly close and overall the concrete was between 4 and 5" all over. The main thing is to have it tied to the rebar tightly so it don't float up as they are working the concrete. I also planned to cut joints in rather than put in expansion joints. I laid out my pex so that where my joints were going to be cut there would be no pex in that part of the slab in as many places as I could but in the few spots that did end up being in the areas that needed to be cut I had put 3/4 grey conduit around the pex in those spots so that if the pex did work it's way up I could see the blade pulling out pieces of plastic before it got down to the pex. After cutting up all the blocks we never hit the grey pipe the first time.
I also took plenty of pics of how the pex was laid out so if I ever need to drill a hole I can go back and look at the pics to decide where I can and can't drill. So far I have drilled the floor 15 or 20 times putting in anchors for partitions and so far so good.
I applied my sealer as soon as I could walk on the concrete without leaving a mark and went back the next day and cut my joints then cleaned it well and put down one more coat of sealer and once it dried good I misted it with water then covered the main floor with tarps and let it sit for a week before I did anything else. After it was uncovered I looked at it for three days with a big grin on my face then started packing junk on it. That was 6 months or more ago and other than it is slick as hell when it is wet it I love it. I hope you love your as much as I do mine.
