i just had concrete added to the floor of my barn: theres a 14 inch drop across the 30ft: i had 12 ft of the high side put in level, then the other 18ft dropped about 4 inches to start, then had about a 3.5 inch drop to the front; it took 24 yards of concrete, at $85 a yard(3500psi with fiberglass), and $1600 to have it formed, poured and finished: i put the fill in the barn with my tractor and leveled it the best i could, i used sb2 for fill(about 40yards), and dug it out to the gnd along the walls, thats where the extra concrete went. 2 guys put in 2 long days: poured the 12X50 on thursday and the 18X50 on friday, and went home about 8:30pm friday night.
heehaw