Conservation bodies such as English Heritage and Historic England approve DOFF steam cleaning because it’s gentle, safe, and keeps surfaces breathable. The system uses low-pressure superheated steam, which lifts staining and growth without eroding brick or stone. Pressure washing is not approved for listed buildings because it is too aggressive — it can strip away historic surfaces, weaken lime mortar, and trap water inside the walls. See how DOFF is used on period and historic properties on our Stone Cleaning and Brick Cleaning pages.
