How many yards of concrete does it take to cover a surface area of 3000 ft 2?

Answer 1

Approximately 44-45 yards would be required to place a 4" thick slab on a 3000SF area. There are 27 cubic feet in a cubic yard, and at 4" thick there is 3 square feet of coverage in a cubic foot:

[# SF] x [# inches thick / 12 inches per foot] / [27 cubic feet per yard]

3000 x 4/12 / 27 = 37 yards

Now, that's ideal. Your surface won't quite be level, so figure on an extra 10-15% for the low spots (you don't want anywhere to be less than 4"). Then figure an extra 5-10% for waste and shortage. You'll drop a bit here and there, and you'll never get all the concrete out of a mixer. You definitely don't want to order too little, so about 45 yards is what you'll need.

Don't forget to cut your slab every 8-10 feet (usually ~1.5" deep with a special piece of equipment called a Soff-cut saw) while it's still curing or you'll get random cracking. Also, make sure you get some structural fibers added to the mix, or use welded wire reinforcement (called WWR of WWF) - to keep any cracks that do form from growing and make the slab more durable.