PURPOSE: To prevent accidents such as falling of tiles by providing lock projections on the building side surface of a board, providing projections at the back of the upper end of each tile, and hooking the tiles to the lock projections of the board for installation.

CONSTITUTION: Three projections 2, 3, 4 each of dovetailed cross section are formed vertically along the overall width of the back of each tile 1 and lock projections 5a of dovetailed cross section are also formed on a board 5 serving as a base. Joints 6 made of an elastic material are mounted between the vertically arranged tiles 1 and secured in advance to the board 5 with an adhesive 7. With the upper edge of each tile 1 butted against the upper joint 6, the lower end of the tile 1 is pressed into the board 5, and the tile 1 is pressed in between the upper and lower joints 6 and locked to the lock projections 5a of the board 5. The tiles can thus be prevented from moving.