Replace broken deck boards
1. Cut out the bad board
The most difficult part of this deck repair task is cutting out the damaged section cleanly. Don't try to cut directly over a joist. Instead, cut to one side and screw on a cleat to support the new decking. It's a fairly hefty cut for a jigsaw, so use a sharp, stiff blade to keep your cuts as straight and smooth as possible.
Draw a square line on the decking to one side of a joist below. Cut the deck board with a jigsaw. Pull the decking nails with a cat's paw.