Locate damaged areas of plywood by looking for water stains on the walls, ceiling and floors. Check for soft or spongy areas on the floor and in the ceiling.
Remove any wall or floor covering to expose the plywood. With a reciprocating saw, cut out the damaged area plus two inches on each side to make sure all of the damage is removed. If possible, cut away enough plywood so that you can attach the new piece to the camper's frame.
Cut a new piece of exterior grade plywood to fit into the area where the damaged wood was removed. Attach the new plywood to the camper with wood screws.
Check the ceiling for damage. Before cutting into the ceiling panels, make sure that they can be removed without compromising the structural integrity of the camper. In vintage campers, plywood may have been used in ceiling panels. To replace plywood in vintage campers, use a reciprocating saw to cut out the damaged area. Cut a piece of new exterior plywood and place it in the area where the damaged wood was removed. Use wood screws to secure the new plywood in place.
