THE ULTIMATE GUIDE TO SUB FLOOR MOISTURE

They're going to also Test that the internal floor DPM (damp-proof membrane) laps in the DPC inside the partitions to form a watertight seal.  The mortar useful for DPC needs to be leveled and even, and will be free from projections so the damp proof course is not destroyed. DPC should be laid in this type of way that a continual projection is off