Greg, are you planning to add a lift in the shop? If so, I would check for what is required for thickness, mesh reinforcement, and the blend mixture. When I bought our current house, it had a 30x48 foot shop already there, with a finished concrete floor. Although I am a bit younger than you (65), I absolutely wanted a 2 post hoist, so I needed to know the type and thickness of the floor, luckily the seller was also the builder, and his brother is a concrete foundation builder, so I had all the first hand information about the garage, including photos of the floor base before it was poured. I would have prefered a 6" thick floor, but the 9000 pound lift I bought said 4 1/2" of mesh reinforced concrete was minimum, and mine is 5"s. Not sure if I would feel comfortable lifting my F350 Dually, but my 3800 pound 59 has been up there multiple times, with no concerns. Although I have not used it, my floor also has built in hot water heat under the concrete, if that was something you were thinking of adding, now is the prefect time to add it. They put the piping in the foundation every 10 inches, so when I drilled to holes for the hoist anchors, I had to do some careful measuring to try to avoid hitting the plastic piping. But even if I hit one, each , each pass of tubing is on a seperate valve, so if needed, I could shut that line off. They also added 4 floor drains, that exit out to a low spot on the property, so I can wash vehicles inside without water building up, although that also meant that they may the floor slanted a bit to direct the water to the drains. Not sure if you plan to go that far, but it is a nice feature.
