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Once the stair stringers are installed, begin constructing the railings. Secure 4x4 posts to the deck using two carriage bolts per post. Ensure the maximum span allowed between posts adheres to local codes. For the main deck section, run the rails on the inside of the posts and secure the balusters to the outside of the rails. For the stairs and landing, the rails were run flush between the posts, with balusters positioned between the top and bottom rails. When installing balusters (typically 2x2s), always pre-drill holes to prevent splitting, as they tend to be brittle. The maximum allowable gap between balusters in most places is 4 inches; a 2x4 (which is actually 3.5 inches wide) can be used as a spacer to ensure compliance. Note that the last baluster in a run might require a different gap due to layout, but you can calculate exact spacing for equal gaps if desired.