Method of forming a surface of an interior wall or a ceiling

A method for forming a surface of an interior wall or a ceiling, comprising:

• providing a pair of building boards, comprising a first building board and a second building board,
• wherein each of the building boards have a pair of parallel and opposite main surfaces,
• wherein a central plane is defined as a plane which is parallel to the main surfaces and which is equidistant from the first main surface as from the second main surface,
• wherein a joint plane is defined as a plane which is perpendicular to the main surfaces and which comprises an outer edge of at least one of the main surfaces,
• wherein edge portions of the building boards have a locking system, for locking the building boards relative to each other in direction perpendicular to the main surfaces,
• wherein each edge portion has a constant profile along the edge portion, comprising a tongue and a groove,
• wherein the tongue is entirely on one side of the central plane,
• wherein the groove is entirely on a second side of the central plane,
• wherein the groove has a height, as seen in direction perpendicular to the main planes, which is at least equal a height of the tongue,
• wherein the groove has a depth from the joint plane, as seen in direction perpendicular to the joint plane,
• wherein the tongue has a protrusion from the joint plane, as seen in the direction perpendicular to the joint plane,
• wherein the depth of the groove is at least as large as the protrusion of the tongue, and
• attaching the first building board to a stud by means of nails,
• joining the edge portion of the second building board with the edge portion of the first building board, such that the tongue of the first building board extends into the groove of the second building board, and such that the tongue of the second building board extends into the groove of the first building board,
• attaching the second building board to the stud by means of nails,
• sanding at least one of the main surfaces of the building boards within an area that extends along the joint plane, but less than 50% of the extent of the building boards as seen in said direction perpendicular to the joint, and
• gluing a surface covering fabric directly to an exposed main surface of the building boards, such that the surface covering fabric covers the building boards.