For 20 years I've been waiting for all the planets to align and allow me to put a concrete floor in my barn... 6" thick, 1/2" rebar on 18" centers, 15 mil vapor barrier. I want to be able to drive any machine inside that will fit through the door!

The pour for the 1st stage starts bright & early tomorrow morning

It would have been a lot simpler to make the slab before the barn. Kind of like putting your underwear on after your pants. But the building was already up when I bought this place... and I have so much junk, and no place to store it, that it was simplest to do the center first. A new slab and 40x60 shop just isn't in the budget and I have waited long enough.
My four-post lift has been in the crate for several years now. You can see it off to the left side.

Next step is to move all the junk onto the slab once it's cured, then do the same prep on the full-length narrow strip and the other square section.