Abstract: Mineral fiber board and process for the production thereof comprising a composite structure of several board layers. The fibers are oriented in a preferred direction in each board layer. The preferred fiber directions of successive board layers cross one another. The board layers are joined by means of a bridge formed from binders, which are added to at least one of the board layers. According to the production process, prefabricated base boards are moved in contiguous manner on a conveyor belt. The fibers of the base boards are at right angles to the conveying direction of the board. A pasty, fibrous mass is applied thereto with the belt moving and this forms the next board layer. The fibers of the pasty mass are preferably aligned parallel to the belt conveying direction. The boards are then dried. The strength, as well as the dimensional and shape stability of the boards are considerably improved.