Stone Primer (Storey Publishing, 2007), by Charles McRaven, presents basic techniques of stonework and dozens of projects for inspiration and practical guidance. Designs for the home include structural masonry and accents like fireplaces and countertops, while landscaping uses include retaining walls, stone bridges, and even stone sheds and water features. The following project is from chapter 3, “Paths and Patios.”
A 3-foot-wide set of stone steps will fit nicely with most paths and is easy to build. The stones you use must be flat and heavy enough to stay in place under foot traffic. It is very important to wedge stones, if necessary, so they are stable — a rocking stone step is very dangerous. As with flagstones, don’t be misled by nice wide slabs of stone that aren’t smooth on top. And remember that only the top surface and leading edge are visible in the finished product.
1. First, estimate the slope by measuring its height from a level, allowing 16 inches for each tread and 6–7 inches for each riser.
2. Dig into the slope to extend an almost level place back about 18 inches and 36 inches wide. Dig down 4 to 6 inches and fill with crushed gravel to just below grade. Lay wide stones, the full 18 inches deep — do not piece stones for the depth of the tread. Use no more than two stones across the 36 inches width of the steps. Smaller stones would tip, rock, settle, and slant. Place the stones rough-side down and dig out for irregularities.
3. Dig back at the height of the top of this step for the next one. Lay these second-step stones (again, no more than two) so as to avoid a running joint. Let the front edges of these stones overlap the backs of the first step stones by an inch or two. Since these back edges will be covered, place the stones so that any rough or uneven edges are here. Shape as necessary, but try to start with good, flat, rectangular stones.
4. Dig out for the third step, just as you did for the others, then lay the final stones, avoiding running joints. Don’t shorten the depth of outdoor treads to meet the slope. Less than 16 inches is awkward to negotiate.