An overhanging edge gives this concrete garden slab a floating appearance. It creates an intimate area for conversation, re-freshments, or just sitting. The method for pouring such a slab is to mound up earth under the edge of the slab to be poured, then dig it away after the concrete has cured . The edge effects a graceful break with the ground.
First mound earth in a circle 6 inches high and 9 feet in diameter. Use two sticks and a rope as a compass to mark a circumference along the top of the mound. Then bend 6-inch-wide sheet metal to make a circular form for a slab 4 inches thick at the edge; stake it in place two inches down in the earth. (Corrugated sheet metal will produce a scalloped edge, but flat sheet metal works as well.) In the center, make another mound of earth to avoid filling with more concrete than necessary. Pour the concrete on standard reinforcing wire mesh.