How to Build a Wood Hand Railing for Balconies

Measure the outside dimensions of your balcony. If the longest dimension is more than 6 feet, install handrail posts so that they have no more than 6 feet between them. Handrail posts are installed by cutting a piece of 4x4 lumber to 8.5 inches longer than the height of your railing. Cut a notch 1.75 inches deep and 10 inches long across one end of the post. Fix the post to the inside edge of the outside joist of your deck with 4.5-inch lag screws that have large washers on them. You may need to cut one of the deck boards to make room for the post. If so, install a block under the new end of the cut board, and fix it to the post.

Install top and bottom sub-railings. These are 2x4s that run between the posts and all the way to the existing corner posts. The top sub-railing should be flush with the top of the post, and the bottom sub-railing should be 1.5 inches above the floor of the deck. Be sure that the railings are level, and then install them with 3-inch screws so that the inside edge of the sub-railings is flush with the inside edge of the posts.

Install the spindles. These are 2x2 pieces that run vertically from the top sub-railing to the bottom sub-railing. The top of each piece should be flush with the top of the sub-railing, and the bottom should be sawed at a 45 or 22.5 degree angle, with the long side placed against the bottom sub-railing. Space the spindles so that the gap between them is less than 4 inches. Screw the spindles into the sub-railings with 3-inch deck screws.

Install the top cap. This is a 2x4 laid lengthwise on top of the top sub-railing, the posts and the spindles. If you need to use more than one board, put the break on top of a post, and cut each end of the two boards at 45 degrees. Lay them together so that the angles meet and a flush joint is created. Screw the top cap to the posts and top sub-railing with 3-inch deck screws.