My plaster is chalky or dusty – why is that?

After applying lime plaster, chemical processes start between the air in the room and the lime. Carbonisation occurs. If the lime plaster loses too much water too quickly during this phase, e.g. due to insufficient substrate preparation, inadequate curing is the result. The lime plaster will then have a lower compressive strength, poorer adhesion and will become dusty or chalky.

To avoid this, lime plaster must be watered in the first 48 hours, if necessary, and draughts and direct sunlight must be avoided, if possible.