Replacing a Deck Plank

  • 01 of 07

    Replacing a Damaged Wood Deck Board

    cupped deck boards
    Wooden deck boards can cup depending on how they are laid down.

    Replacing a rotted, split, or otherwise damaged deck board is almost as simple as cutting out the old board and replacing it with new material. The only additional step is installing lumber support blocks alongside the joists (the horizontal structural members supporting the deck boards). This method works well if you don't want to remove and replace the entire board. Alternatively, you can simply remove the old board entirely and replace it with a matching length of new decking. 

    Supplies Needed:

    • Eye protection
    • Speed square
    • Pencil
    • Jigsaw
    • Drill-driver
    • Pressure-treated 2x4 board, 24 inches long
    • Tape measure
    • Circular saw or miter saw (optional)
    • 1/8-inch drill bit
    • 2 1/2-inch and 3-inch deck screws
    • Deck board lumber that matches the old deck boards
    • Deck wood finish (as needed)
    Continue to 2 of 7 below.
  • 02 of 07

    Plan the Cut

    Examine the area around the damaged section of board, noting the locations of the neighboring joists. The goal is to cut out the damaged section cleanly and make the repair look as natural as possible. It looks best if the cuts are at least one joist space away from the joints on any adjacent boards. The cut-out section must span at least two joist spaces, for long-term stability. Identify the two joists where you will make the cuts to remove the bad section of deck board. Use the speed square to mark the bad deck board along the inside face of each joist. 

    Continue to 3 of 7 below.
  • 03 of 07

    Remove the Bad Section

    Put on eye protection. Cut along the marked lines on the deck board, using a jigsaw. You can use the speed square to guide the saw, if you're comfortable with this technique. Otherwise, simply follow the line carefully for a straight cut. The saw blade should cut right along the inside face of the joist. Remove the screws securing the damaged section of deck board, using a drill-driver (if the board is nailed, pry up the nails with a cat's paw or pry bar). Remove the board section. 

    Continue to 4 of 7 below.
  • 04 of 07

    Cut the Support Blocks

    Cut two 12-inch-long sections of 2x4 lumber for the support blocks, using a circular saw, miter saw, or jigsaw. Drill two pilot holes through each block, about 2 inches from each end, using a drill and 1/8-inch bit. 

    Continue to 5 of 7 below.
  • 05 of 07

    Install the Support Blocks

    Position each block against one of the inside faces of the joists where you made the cuts so the block is centered under the opening where the board was removed. Pull up the block so it is tight against the undersides of the neighboring deck boards. Fasten the block to the joist with four 2 1/2-inch deck screws. Install both blocks using the same techniques. 

    Continue to 6 of 7 below.
  • 06 of 07

    Cut New Deck Board

    Deck Board Bark Side Down
    Bark Side Down Deck Board. © 2006

    Cut the new deck board to fit snugly in cut-out area. Note the end-grain pattern of the replacement board: If the rings of the end grain are roughly parallel to the board's width (grain runs side to side), position the board so the curve of the rings faces down (this is called the bark side and indicates where the bark was on the tree). If the grain is perpendicular to the board width (grain runs up and down), you can place the board either way, but if it has a slight cup, or curve, place it with the convex side facing up. This will help prevent cupping as the board weathers.

    Continue to 7 of 7 below.
  • 07 of 07

    Install the New Deck Board

    Place the board onto the support blocks with the bark side or concave side facing down. Drill two pilot holes through the board at each end, about 3/4 inch from the end (so the holes are centered over the support block thickness). Also drill a pair of pilot holes at any other joists that the board spans over. Fasten the board to each support block (and any joists) with a pair of 3-inch deck screws. Finish the new board to protect it from weathering and to match the coloring of the existing decking.