Fixing a wooden fascia board involves inspecting and removing the old board, filling the rotten parts of the board, painting the board and reinstalling the board. If needed, cut off the parts of the board that are not repairable with a reciprocating saw and replace the board with a new one. You need a reciprocating saw, a screwdriver, epoxy wood filler, a drill and paint to complete this task. A paintbrush, a chisel and primer are also handy.
Inspecting the board helps you to determine the extent of the damage. To do so, access the board using scaffolding, and try to pierce it with a screwdriver. Check the rafters for rot as well. To remove the old fascia board, start by detaching the gutter downspouts from the gutters, removing the screws that secure the gutter brackets in place, and detaching the gutters. Pry the board off the rafters with a crowbar, taking care to use the drill in case the gutters are attached to the rafters with screws.
One the board is off the rafters, chisel off the rot from the board, and apply the filler. Repeat the process for the rotten rafter ends. Allow the filler to dry, apply the primer, and allow the primer to dry before applying the paint. Allow the paint to dry, and secure the board to the rafters with screws. Replacing the gutters and gutter downspouts completes the process.