| 摘要 |
A building board which is provided on the surface thereof with a concave and convex pattern, and opposite sides thereof with overlying rabbeted portions (2-1, 6-1, 6-2) and underlying rabbeted portions (3-1, 3-2, 5-1), respectively, wherein each overlying rabbeted portion (2-1, 6-1, 6-2) is constituted by one end portion of the convex portion (2, 6) of said pattern; each underlying rabbeted portion (3-1, 3-2, 5-1) is constructed to have an area bigger than the area of corresponding overlying rabbeted portion (2-1, 6-1, 6-2) bearing said convex portion and formed on the opposite side; and each of said opposite sides is provided on the rear side thereof with a linear contact surface (7-1, 7-2). |
