This section is from the book "A Treatise On Architecture And Building Construction Vol2: Masonry. Carpentry. Joinery", by The Colliery Engineer Co. Also available from Amazon: A Treatise On Architecture And Building Construction.
113. All area steps, when practicable, should be of stone or a combination of stone and brick. Areas that are more than 6 feet deep, or where the soil is sandy, gravelly, or a wet clay, should be excavated under the steps, and the steps themselves should be entirely surrounded by a wall.
The foundations for all outside stone steps, fence coping-, etc. should be carried at least 2 feet below grade, and if built in localities likely to be affected by frost, they should be carried below the freezing line.
If the soil is hard and compact, or in localities where it is not subject to upheaval by frost, small flights of steps may be economically built by shaping the treads and risers in the earth, and laying two courses of brick in cement for the risers, and 2-inch stone flags for the treads, as shown in Fig. 44. Nothing but cement mortar should be used in setting the steps, which should be well pointed on completion, and the ends of all the stone treads built into the side of the earth walls.
114. Either solid stone blocks or 2 to 3 inch stone flags may be used in forming the treads and risers, the side wall in either case supporting the ends. If the steps are made of solid stone, the front of each block should rest on the back of the block below it, as shown at (a), Fig. 45. If the treads and risers are made of stone flagging, they are arranged as shown at (b) or (c), Fig. 45. The best arrangement is shown at (b). When the steps are more than 5 feet long, a bearing wall or iron string piece should be built under the middle of them. There should always be a pitch, from rear to front, of 1/8 of an inch in the width of the tread, to secure the proper drainage.
Plank steps supported on plank string pieces are used in many localities; also iron steps with plank treads. The ground should be excavated, and the area walled up under them. When the plank treads decay or are worn out, it is a matter of small expense to replace them. The steps should finish on a platform made of cement, flagging, or brick, ending at least 4 inches below the top of the entrance door sill.