A device and a method for the production of a fiber mat is suitable in particular for use in the production of packaging board or fibrous construction elements, from a fibrous source material. The method includes providing the fibrous source material, low-water processing of the fibrous source material in an airflow into raw material including individual fibers and/or fiber bundles, forming of the individual fibers and/or fiber bundles in the airflow by a dry forming method into a fiber mat in such a way that a spatial or three-dimensional structure is formed by the fiber mat and consolidation of the formed fiber mat. The specific volume of the fiber mat is greater than 1.6 cm3/g, in particular greater than 2 cm3/g, preferably greater than 3 cm3/g, and the fiber mat thickness ≥1 mm, in particular ≥1.5 mm, preferably ≥2 mm.