MANUFACTURE OF SUBSTRATE PLATE MATERIAL FOR DRY EXECUTION

PROBLEM TO BE SOLVED: To enhance a degree of freedom of the surface shape of a substrate plate material for dry execution by cutting a part of a protrusion, and forming a hooking part inclined downward from frontward to rearward after the protrusion swelled from the surface of the substrate plate material is formed. SOLUTION: A substrate plate material 2 providing a protrusion 2c having a protrusion inclination face 2d swelled from the surface of the substrate plate material 2 by press forming and vertically inclined and symmetrized is formed. Next, a cutting part 2e from the protrusion inclination face 2d of the upper side is cut into a shape in parallel with the protrusion inclination face 2d of the lower side by cutting processing. Since a hooking part 2b inclined downward from frontward to rearward is formed on the upper side of the protrusion 2c by cutting processing of the cutting part (e), the substrate plate material for dry execution 2 of construction material such as a tile can be manufactured by press forming of a high degree of freedom of surface shape.