An area of approx. 7.000 m² of walls and ceilings of an underground government facility were leaking and a lot of condensate was falling out on the surface of the existing cementitious plaster. The old cementitious plaster was removed. Ceilings and walls were waterproofed from the negative side with the KÖSTER KD System and with KÖSTER NB 1 Grey. Then, the whole area was prepared for plastering with a plaster key before KÖSTER Restoration Plaster II “Light” was applied to ceilings and walls.