If you are trying to figure out how many "yards" for a certain area.
You would multiply the length x width x depth, divided by 27 = the yards.
example: 24' x 24' x.5 =288 / 288 divided by 27 = 10.6 yards total
So 24' x 24' , 6inches thick will use 10.6 yards.
There is also factors for...