Abstract: In order to be able to mount a suspended ceiling in places where the space between the ceiling and the overlying structure exceeds 40 mm there is according to the invention used a generally known metal suspension element (2, 3) with a T-iron (4,5).On these T-irons (4,5) there are mounted plaster boards (6) in that on the back of the boards there are glued two metal strips (7,8), i.e. one with a backwardly bent edge (8) overlapping one of the flanges (5) and a metal strip (7) abutting on the flange (5) in the mounted position of the board. It is thereby possible to place the boards loosely and to take them down according to requirements without any need of tools. The structure will allow the mounting of an additional insulation layer on top of the boards (6). At the same time the structure will appear as plane ceiling surface i.e. with concealed support profiles (4,5). This simplifies maintenance.

Abstract: A perforated panel having a thickness of at least about 6 mm, for use as a sound absorbing element, especially at lacunarias. Each perforation is covered by a thin fiber cloth which is bonded to the edges of the perforation, rendering said panel element a specific acoustic flow resistance of between 1200 and 4000 Nsm.sup.-3.