4.938 cubic yards.
4.074 cubic yards for every foot the slab is thick.
How many square yards in a 20x18 feet 3 inches thick
16 * 20 = 320 sq ft. at 4" thick concrete will cover 80 sq ft. 320 / 80 = 4 yards.
1.62
one (1) cubic yard of concrete four inches thick will cover 80 sq. feet. 85 yards x 81 = 6885 sq. feet.
996 square feet X 1/3 foot = 332 cubic feet.332 cft / 27 = 12.3 cubic yards
You will need 17.8 cubic yards of concrete.
10.67 Cubic Yards
532.4074 yards of concrete, round up to 533 yards.
6.94 Cubic Yards
3.6 cubic yards will be enough.
10 yards
6.67 Cubic Yards
4.074 cubic yards for every foot the slab is thick.
15 cubic yards
15 cubic yards
At 4" thick you will need 1.23 cubic yards.