The steam/superheated water will remove moss, algae, fungi and other biological matter and will also kill off spores. This means there’s then no need to use a chemical biocide during the removal process or as a protection against further biological activity.
DOFF cleans stonework and masonry using high temperature steam. Whilst the temperature in the system is high, the pressure on the surface being cleaned is very gentle and the volume of water is low. The surface is therefore not saturated and will be dry within minutes.