The classification is made in accordance with the leaflet no. 2, Filling of gypsum boards, surface qualities, notes and guidelines for drywall construction work with gypsum board systems, published by the gypsum board industry group in the Federal Association of the Gypsum Industry e.V.:
*The described extent of the filling refers to the uppermost plasterboard layers. For the lower layers, the filling is usually limited to filling butt joints.
Source: bauwion
