As deck wood ages over time, the boards can begin to rot, crack, or come loose. This can occur if the deck boards have not been properly maintained with routine cleaning, staining, and sealing. Repairing deck boards can be as simple as tightening a few screws, but rotted or cracked boards must be replaced. This is an easy do-it-yourself project that does not require a permit or, in most cases, rebuilding the deck structure, because the posts and beams are not directly exposed to the elements and typically outlast the deck.
You can save a lot of time and money by replacing only the worst deck boards instead of the entire deck.
Remove Bad Deck Boards
Identify the deck boards you are replacing. If you are not removing the entire deck board, decide where you will make the cuts at least one joist space from the end of the neighboring boards and make sure the remaining portion of the old deck board, if any, and the new board cover at least two joist spaces. Cut the damaged deck board flush with the joist or along the centerline of the joist with a circular saw. To avoid cutting notches into neighboring boards with the circular blade, use a jigsaw or oscillating multi-tool to finish the cut. If you cut along the centerline of the joist, remove any nails or screws from the cut line or move the cut line to avoid them.
Inspect Joists, Beams, And Posts
Removing deck boards will expose the joists. Inspect them for rot or other damage and make sure they are securely fastened to the posts and batten. Also inspect the joists for rot, especially if they are in contact with the ground. Check that the joist supports are plumb, free of rust, and that they are not missing any fasteners. If you find rot on any structural members, decide whether to repair or replace them and learn how to avoid and prevent rot in the future.
Add Support Brackets And Reinforcing Beams
If necessary, add battens or twin beams to support replacement deck boards and reinforce damaged joists. Attach the batten or beam with framing nails or structural screws to the existing joist where you cut a deck board and anywhere a joist needs reinforcement. Make sure the top of each batten or beam is flush with the top of the existing joist. Apply a sealant to the top of the joists to help them resist rot.
Cut The New Deck Boards
Measure the distance between the existing deck boards. If possible, use a single board to span the gap and leave a 1/8-inch gap for expansion at each end. Each board should span at least two joist spaces, and cuts should be staggered with those of neighboring deck boards. Avoid cuts that leave knots at the ends of the board.
Installing New Deck Boards
To prevent cupping, install new boards with the bark facing up so the grain pattern is convex. Use 3-1/2-inch deck screws to attach the boards. Drilling pilot holes will make the job easier and help prevent cracking, especially at the ends of the boards. When installing new boards, make sure there is even spacing between each adjacent board.