Patent ID: 7661511

Claim:
A board for use as a building material with a fixing element having a head, the board comprising: a gypsum board formed with a gypsum core; a first sheet of liner paper applied to the gypsum board to define a first surface; a plurality of perforations disposed on the first surface of the board, the perforations being constituted from a number of visible recesses, or a number of visible recesses and visible through-holes, the perforations having a shape that is a polygon or a circle, and said visible recesses being formed on the first surface of the board by compression-forming for locally compressing the gypsum board, and wherein each recess has a visible bottom face that is exposed and formed by the first sheet of liner paper continuously extending from the liner paper on the first surface of the gypsum board without breakage, the bottom face of each visible recess providing a face to be secured by the fixing element thereto, and the exposed head part of the fixing element being contained in the recess.