How to Put Rails on a Porch

Extend the tape measure along the edges of the porch to measure its length. Divide the span of the porch into equal parts for the rail posts. Mark the locations of the posts on the porch floor with masking tape.

Calculate the thickness of the porch floor joists and the flooring materials, and add the measurements. Add this measurement to the finished post height when cutting your 4-by-4 lumber with a miter saw. For instance, if you want the posts to stand 36 inches high, include the sum of the joist and floor depth to the post length when cutting the lumber.

Cut a small rectangular opening through each marked post location along the edge of the porch, using a jigsaw blade.

Stand a post into the corner hole, ensuring that it rests on a level paver on the ground. Using a right-angle drill, bore a series of pilot holes through the porch framing from a spot below the porch. Insert a lag screw into each hole to secure the lower end of the post to the joist. Tighten the screws with a wrench as you work. Continue to secure the remaining posts in the holes.

Measure the space between two adjacent posts and cut 2-by-4 lumber to size for the upper and lower rails that hold the vertical balusters.

Cut prefinished balusters to lengths of 36 inches, using a handsaw. Lay a piece of 2-by-4 lumber on the table and position a baluster on its corner. Mark the edges of the baluster on the rail with pencil. Move the baluster 4 inches away along the lumber and mark its edges again. Repeat this process to mark the edges of the balusters along the rail, spaced 4 inches apart.

Join the balusters to the 2-by-4 rail. Insert a screw through the underside of the rail into the center of each baluster. Ensure the edges of the balusters match with the marked outlines on the rail.

Attach the upper 2-by-4 rail to the upper ends of the balusters, parallel to the lower rail, to complete one section of the porch rail. Drive two screws through the upper 2-by-4 rail to attach it to the upper edge of each baluster.

Set this rail section between two posts along the porch, with the lower rail resting on the porch floor. Use the right-angle drill to drive screws from each side of the rails that extend into the posts. Repeat this process to construct and install remaining rail sections to the porch.