To replace fascia boards, measure the width of one board, purchase a board sheet according to the measurement, prime and paint the new sheet, cut it to specified measurements, pry off the old boards, and install the new boards. Wear safety glasses when working. A circular saw, reciprocating saw, hammer, ladder and measuring tape are necessary for the replacement. Galvanized nails, a paint brush and a silicone gun are handy as well.
Use a ladder to reach damaged fascia boards. Use a measuring tape to measure the width of a damaged board, and use the measurement to purchase a board sheet. Alternatively, use outdoor ply in place of fascia boards. Apply primer to the new sheet, and paint it accordingly.
Use the claw of a hammer to remove the faulty boards. Measure the length of the boards, and use the measurements to cut pieces of the same size as the faulty boards from the board sheet.
Place the replacement board on the raft, next to adjacent boards. Use nails to fasten the lower section of the board to the raft. Repeat the process for other boards. For damaged or rotten rafters,
cut 2-by-4-inch boards, and secure the boards on the ends before nailing them boards in place. Apply silicone sealant along the edges and joints of the boards, and paint the edges of the boards if necessary.