Nancy and I sliced up about 20 sheets of 5/8" AC plywood into 11 3/8" wide strips and I've been fastening them down in a grid pattern for the Pex tubing (see Day 92 blog). With the 5/8" Pex between the strips, the Pex is on 12" centers, just like the Warmboard. I laid all 80 strips (8' long, with miscellaneous filler pieces) in about 8 hours. It was easy, but my knees took a hit (hello Dr. Advil). Today I started the custom routing of the 36 return loops (ends) and the plunge holes (where the tubing goes downstairs), which will take 6-8 hours considering how feeble carpenter is. We'll have 2 heating loops upstairs, each about 280 ft long (300 ft is the max) in a third zone for heating. We wanted to be able to heat the Love Nest when and if needed, so Levi added a third manifold and Taco pump (1/40 hp) on the basement heating panel. I also had him add temperature gauges (old analog style) for the outgoing and returning radiant fluids, since I like gauges and data (old geologists never die, they just loose their data).
Gary Ellis loaned me his standup screw gun. What a tool. It loads 50 drywall screws per plastic strip and feeds them like machine gun bullets. 20 strips and 1000 screws to a bucket. Started screwing down the aforementioned strips (11 3/8"), and drove a screw in each side every 12-16". Did the whole bucket and floor in 75 minutes, including misfires, which equates to 133 screws a minute. Not bad for an old fart. All my screwing is done for a while.
It'll take a week of part-time days to route the ends and lay and caulk the tubing, which I bought from PexSupply, currently my favorite place to spend $$ on the internet. I'm buying a Pex Expander Tool ($300) for making all the connections with the hopes of selling it used on the internet (Craigslist) or to Levi Ross, who has started his own radiant consulting business.
