Slabs Brentwood Slab Weight: 15 lbs. per sq. ft. (28 lbs.) Brownstone Slab Weight: 26 lbs. per sq. ft. Indiana Limestone Slab Weight: 26 lbs. per sq. ft. (39 lbs.) PA Bluestone Slab Weight: 19 lbs. per sq. ft. (26 lbs., 39 lbs.)