A layer of impervious material (i.e. water can't pass through), which prevents moisture rising from the ground into the walls of a building.
a course of some impermeable material laid in the foundation walls of building near the ground to prevent dampness from rising into the building
A waterproof membrane installed in walls and floors to pre- vent moisture causing damage by rising upwards through the structure. Also termed 'damp course' or 'DPC'.