1. Cut 4 × 4 railing posts to size (at least 36", plus the height of the deck rim joists). Lay out and mark partial dadoes 1 1/2" wide and 2 1/2" long where the horizontal 2 × 2 rails will fit. Use a circular saw set to 1/2" blade depth to make a series of cuts from the edge of the post to the end of layout marks, then use a chisel to clean out the dadoes and square them off. On corner posts, cut dadoes on adjoining sides of the post.

2. Attach the posts inside the rim joists. To find the length for the rails, measure between the bases of the posts, then add 1" for the 1/2"dadoes on each post. Measure and cut all balusters. Install the surface boards before continuing with railing construction.

3. Assemble the rails and balusters on a flat surface. Position the balusters at regular intervals (no more than 4" apart), and secure them by driving 2 1/2" deck screws through the rails. A spacing block cut to match the desired gap can make this work easier.

4. Slide the assembled railings into the post dadoes, and toenail them in position with galvanized casing nails. Cut plugs to fit the exposed dadoes, and glue them in place. The resulting joint should resemble a mortise-and-tenon.

5. Measure and cut the 2 × 6 cap rails, then secure them by driving 2" deck screws up through the top rail. At corners, miter-cut the cap rails to form miter joints.