How to Fix a Wood Opening in a Gate Door

Remove fasteners or wood scraps that remain attached to the top and bottom rails of the opening using a pry bar or a power drill equipped with a screwdriver bit. Measure the height of an intact fence board with a tape measure. Although most boards are milled to standard length, usually 5 or 6 feet, you might need to cut your replacement board to size.

Latch the tape measure's clip onto the beveled end of the replacement fence board, commonly called the "dog eared" end. Stretch the tape to the required height and mark the position of the cut with a pencil. Align a framing square with the mark and lay the square across the board's face. Draw a pencil along the square's edge to lay out a cut line.

Measure the width of the gap between the gate's intact boards with a tape measure. Mark the gap width on the top and bottom rails in the opening, measuring from the surrounding intact boards to the inside of the opening.

Cut the board to size with a circular saw. Lift the board against the gate and insert the board into the gate's opening. Align the bottom edge of the replacement board with the bottom edges of the adjacent boards. Shift the replacement board left or right and align its edges with the gap marks on the top and bottom rails.

Hold the board in position and drive four nails through the board using a hammer, with two nails at the center of the top rail and two at the center of the bottom rail. Alternatively, fasten the board to the gate's top and bottom rails using a power drill and deck screws. Space your fasteners away from the replacement board's edges to prevent the wood from splitting.