PURPOSE: To provide a stepped tiling structure laying stress on the appearance, and enable a waterproofing and moisture control function to be maintained.

CONSTITUTION: This structure for modifying an existing newly tiled roof, comprises stepped tiling roof materials C having jointing pieces formed with both lengthwise ends of decorative surface l bent inside, and round tiling materials A and B having jointing pieces of approximately semi-conical form comprising an upper engagement piece bent toward the decorative surface 1, a lower engagement piece bent inside, and both right and left sides of the decorative surface bent inside. Furthermore, the structure comprises a rain stopper section, a joint material, a lining material D and a waterproof sheet F. This waterproof sheet F is laid on the hip of the existing newly tiled roof in a direction from an eaves to a ridge, and the roof material C and round tiling materials A and B are laid on the lining material D at each level. The materials A and B are coupled and hooked to each other. The jointing piece of the roof material C is coupled to one engagement tongue of the jointing material, and the jointing pieces of the materials A and B, and the other engagement piece of the jointing material are coupled and hooked to each other, thereby jointing a whole structure.