1. Cut posts to length, then mark the bottoms of the posts for 1 1/2"-deep notches that will allow the posts to fit flush with the outside edges of the rim joists. Make the cross-grain cut first, then set the circular saw to maximum blade depth and make rip cuts from the end of the post to the first cut. Remove the waste wood, and use a chisel, if necessary, to square off the shoulder of the notch. NOTE: A wall-style railing generally requires posts only at the open ends.

2. Attach the posts inside the rim joists with 2 1/2" lag screws, then add blocking between joists to reinforce the posts. Install decking before continuing with railing construction.

3. Build a 2 × 4 stud wall to match the planned height of your railing. Space studs 16" on center, and attach them by driving deck screws through the top plate and sole plate.

4. Position the stud wall on the deck, flush with the edges of the rim joists, then anchor it by driving 3" deck screws down through the sole plate. At corners, screw the end studs of adjoining walls together. At open ends, screw the end studs to posts.

5. At corners, attach 2 × 4 nailers flush with the inside and outside edges of the top plate and sole plate to provide a nailing surface for attaching trim boards and siding materials.

6. On inside corners, attach a 2 × 2 trim strip, using 10d splitless cedar siding nails. Siding materials will be butted against this trim strip.

7. On outside corners, attach 1 × 4 trim boards on both sides, so one board overlaps the end grain of the other. The trim boards should extend down over the rim joist. Also attach trim boards around posts.

8. Cut and position cap rails on the top rail, then secure them with 2" deck screws driven up through the rail. Railing caps should be mitered at the corners.

9. Attach siding materials to the inside and outside faces of the wall, using splitless cedar siding nails. Snap level chalk lines for reference, and try to match the reveal used on your house siding; the first course should overhang the rim joist slightly. Where joints are necessary, stagger them from course to course so they do not fall on the same studs.