​Soft washing is cleaning with low pressure, involving the application of  a cleaning agent or agents (surfactant's, biocides, anti fungal etc),  which will neutralise and remove
​contaminates leaving the surface clean and safe ​​

Green algae covered wall,cleaned and treated by softwashing.  (10 mins in 20 seconds)

Buildings and there surrounds are naturally made up of different materials, both natural
​or man made, ​requiring different treatments to clean and restore them.