[Evans, Marv]

A 10x12x4 in. slab is 40 cu ft., which comes out to about 1.5yds. of concrete. Each ready mix bag is 2/3 of a cu. ft. (at least the ones I've bought at H.D.), which equals 61 bags (not including any extra to cover irregularities). I did a slab like that once and bought the one cubic yard trailers of ready mix. It worked out great. The only thing I didn't like about it was the bumping on the road towing them home made the concrete aggregate settle a little and I had to mix it up when I got it home, plus it started to set up a little. I used the extra half yard for an apron. Since then I've made a few sheds with concrete piers rather than slab. I like it better. I leveled the area, set 12 (or 15?) piers leveled, ran ten foot pressure treated 4x4's and laid 2x4's perpendicular, flat side down with maybe half in. or more spaced between & covered them with plywood sheets. I used lag bolts to secure the base plates.