Most steel railings are made of vertical bars welded to a frame of crosspieces and posts. The crosspieces may form a parallelogram following the angle of a stairway, or they may form a rectangle along the edge of a porch. An ornamental strip of molded cap rail typically tops this frame. You can join a series of frames to several posts to make a long railing.
Whatever the configuration of a railing, the bars usually are solid steel ½-inch square. Get posts of 11-gauge steel tubing 1-inch square or — for extra strength — of solid steel 1-inch square. Traditionally, you’ll use crosspieces of 1-inch channel iron punched with square holes for the bars. You’ll weld the molded cap rail onto the top channel. However, you can save time and money by using a cap rail with the top channel already molded into it. Flanges parallel to the edges of the cap rail anchor the bars in place for welding.
Before making a railing for either a stairway or a porch, check the building-code requirements where you live. Use these as the basis for planning the railing and ordering materials.
When you order materials, ask the supplier to cut the steel to length. The cap rail should equal the length of the railing, plus 5 inches for each decorative curve at the ends — 6 inches if the curve is at the bottom of a stair railing. For a railing like the one shown here, determine the length (excluding the curves) by measuring from the edge of the top step to the edge of the bottom step and adding 2 inches for the two posts. Use this figure for the channel as well, and then make adjustments during construction.
To find the height of the bars, add ½ inch to the distance from the lower channel to the bottom step, and subtract this sum from the railing height; the location of the lower channel and the height of the railing are usually set by code. The length of the posts will depend on how you anchor to the stair or porch. If you set into holes drilled in concrete, they should equal the railing height plus 4 inches. However, if the porch or stairway is concrete covered with a brick veneer, add 3 more inches to allow the post to pass through the veneer and into the concrete below. If the porch or stairway is of concrete shallower than 4 inches, order posts that equal the height of the railing, and anchor them with post flanges and lag bolts.
Ask the steel supplier to prepunch the channel to hold the bars. An interval of 6 inches, center to center, satisfies most building codes. For a diagonal railing, the holes must be slightly rectangular — ½ inch wide and â…? inch long. If the supplier cannot prepunch and shear the steel, cut it yourself with a hacksaw, then drill and file the holes.
Once the metalworking materials are at hand, draft a full-scale template for the metal railing on a 4-by-8-foot sheet of ½ inch plywood. Because one edge of the plywood serves as a reference for all the measurements, that edge must be smooth and the corners square.
To make the butt welds and fillet welds that hold the railing together, you also need a supply of E6013 electrodes â…› inch in diameter. Once you have made the welds, grind the butt welds smooth, coat the railing with rustproof primer, and finish it with black exterior enamel made for metal surfaces.
Before you begin welding, be sure you thoroughly read, understand, and follow the Safety Rules for Welding. It is essential to dress yourself properly and maintain a hazard-free workshop. When bending metal with oxyacetylene equipment you must, as when welding, wear a tinted welding face mask or tinted welding goggles to protect your eyes from sparks and glare. You will also need insulated welding gloves, welding jacket, and a shop apron or coveralls.