Traditional concrete slab-finishing practice entails an unavoidable wait for the concrete to stiffen sufficiently before the first floating operation can take place. This delay often entails considerable overtime. The overtime can be largely eliminated by removing excess water from the concrete by a vacuum process immediately after the initial compaction and leveling stage of slab construction. One, cover the fully compacted and accurately leveled slab with filter sheets appropriate to the size of suction mat provided. Two, when filter sheets are moved to an adjoining area, place them so as to abut but not overlap the area just dewatered. Three, if dewatering equipment with a flexible top suction mat is being used, place the rolled-up mat centrally on the area to be dewatered and then roll it out flat so that it covers the filter sheets and projects an extra 150 millimeters all around onto the fresh concrete. Four, make sure the top suction mat is lightly imbedded onto the concrete all around. Five, connect the hose from the mat to the vacuum pump and start the suction. Six, keep the suction at the amount of vacuum recommended by the manufacturer of the equipment for about one and one-half minutes for each 10 millimeter of slab thickness. Seven, just before stopping the vacuum pump, break the suction on the concrete by lifting the edge of the top suction mat for a few seconds. Eight, after the suction is shut off remove the mat and filters. A man can stand on this surface immediately. Finally, nine, continue with additional placing and leveling of concrete while an area is being dewatered so that good construction progress is maintained.