Area Per Ton Coverage: Flagstone coverage: 120 sq. ft. per ton up to 1½" thick: Flagstone coverage: 80 sq. ft. per ton up to 2" 2¼" thick: 2" 4" rock coverage: 60 sq. ft. per ton: 4" 8 " rock coverage: 40 sq. ft. per ton: 4" strip stone coverage: 55 sq. ft. per ton: 8" wall rock coverage: 20 sq. ft. per ton