To provide multistage tile-like repair material facilitating replacement work.

After replaced multistage tile-like external facing material (10A) is removed to form replacement space 40, a throating board 30 is inserted in the space 40 and fixed in a position where a replaced multistage tile-like external facing material throating part 15 was before. A throating part 15 of a multistage tile-like external facing material 10 is removed, and a multistage tile-like repair material 21 is formed, inserted in the space 40 and adjusted into a position where the external facing material (10A) was before. A bonded part 23 of the repair material 21 is positioned on the throating board, and the repair material 21 and the adjacent multistge tile-like external facing material are bonded to each other.