Pro tip: my garage slab is 4 inches thin and I learned it from a $12 drill bit
I was drilling anchor holes for a new workbench last Saturday and the bit punched through into dirt faster than I expected in my two car garage in Akron. A neighbor who does concrete said that means my slab is only about 4 inches, which is way thinner than the 6 inches I just assumed every garage had. Now I am second guessing every heavy thing I bolt down, so how do you folks figure out slab depth before drilling?