Build material handling unit for a powder module for an apparatus for additively manufacturing three-dimensional objects, which apparatus is adapted to successively layerwise selectively irradiate and consolidate layers of a build material which can be consolidated by means of an energy source, wherein the build material handling unit is coupled or can be coupled with a powder module, wherein the build material handling unit is adapted to level and/or compact a volume of build material arranged inside a powder chamber of the powder module by controlling the gas pressure inside the powder chamber.