How deep? Are you talking about dry mix weight or finished weight?
Concrete weighs 150 pounds per cubic foot. So if you have a 6" slab, that's 150# for 2 square feet. For a 4" slab, the same amount will cover 3 square feet. For a 3" slab, 4 square feet.
Concrete mix is commonly sold in 80 pound bags. The finished weight is the mix plus the water that gets chemically bound to it. There's a guide on the bag telling how many bags you need for a given area and thickness.
1 cubic yard of concrete fills 27/depth in feet square feet.
81 square feet
it equals nine square feet * * * * * Nine square feet is 1 square yard, NOT 1 yard. In any case, "a yard" of concrete is used by builders' merchant to mean a CUBIC yard of concrete.
A yard of concrete is a cubic yard and cannot be converted directly to square feet of coverage. You must first determine the depth or thickness that the concrete will be. For instance, since 1 cubic yard equals 27 cubic feet, a 1 foot thick layer of concrete will cover 9 square yards of area. A 4 inch (1/3 foot) thick layer would cover 27 square feet of area.
To what depth?
1 cubic yard of concrete fills 27/depth in feet square feet.
One square yard is nine square feet, so 27 square feet is equivalent to 3 square yards. So 3 yards of concrete will cover 27 square feet.
81 square feet
it equals nine square feet * * * * * Nine square feet is 1 square yard, NOT 1 yard. In any case, "a yard" of concrete is used by builders' merchant to mean a CUBIC yard of concrete.
If it is the same as concrete it will cover 162 square feet. concrete covers 81 square feet by 4" deep
27 square feet at 1 f thick
About 162sf.
1 cubic yard covers 324 square feet per inch of thickness, divide 324 by thickness in inches to get coverage, i.e. 4 inches thick would cover 324/4=81 square feet, 36 inches thick would cover (you guessed it) 9 square feet.
A yard of concrete is a cubic yard and cannot be converted directly to square feet of coverage. You must first determine the depth or thickness that the concrete will be. For instance, since 1 cubic yard equals 27 cubic feet, a 1 foot thick layer of concrete will cover 9 square yards of area. A 4 inch (1/3 foot) thick layer would cover 27 square feet of area.
go to any search. and type in concrete calculater
90
30' x 20' (600 square feet) = 66.6 square yards.