Has your historic building got years of moss and algae build up?

Are you worried cleaning the stone will damage the surface?

Our Service

Protecting the surface of your building is key when cleaning a historic building. 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 resulting in unsaturated stonework  that will be dry within minutes. The aim is to clean and remove dirt, staining and biological build up without damaging the surface or altering the patina of the stonework.

Biological matter can build up on most exterior surfaces, from walkways to step and paths. When wet, the surface can become extremely slippery. Our specialist systems are able to remove this build-up from multiple surfaces reducing the risk of slips and falls.

Biological Matter

The build up of biological matter over several years will result in staining to a buildings surface. The use of high pressured water does not only fail to remove the biological matter and subsequent staining but it also causes lasting damage to the surface. Keystone are able to remove moss, algae, fungi and other biological matter using only steam. The high pressure kills off spores meaning there is no need to use a chemical biocide during the removal process as a protection against the return of further biological matter.

Surface Pollutants

Leaking downpipes and drains are a common cause of discolouration and staining to stone and paintwork. Years of continual build-up can cause lasting staining which cannot be removed by high pressured water. Using steam with temperatures that reach 150 degrees Celsius, Keystone Preservation have an overwhelming success rate in removing pollutants from a building surface whilst causing zero damage to the stonework.

Temperatures are lowered for painted surfaces to ensure only the stains are removed and the paintwork remains chip-free.


For more information, please get in touch with our team: