This project involved the Thermal or “Doff” cleaning of Accrington Town Hall in Lancashire for the Queens Diamond Jubilee. As a specialist cleaning contractors we used a high temperature steam system to remove algae growth from the facade of the Hall.
Our specialist cleaning contractors used a large scissor lift to access the high levels of the town hall. All our operatives are IPAF approved, with experience in the use of scissor lifts & aerial platforms. We installed barriers & safety signage the area below the platform. There was also a banks man at the ground to ensure the public did not enter the work area. The protection to the public was of our up most priority.
The Stonework on the building had growth material where shaded from sunlight. Our task was to remove this growth using our specialist techniques. The stone on the old listed town hall building is soft yellow sand stone. The thermal system or “Doff” use’s super heated water to 150 C. The system uses a normal water supply which is taken into the high pressure pump unit and the pressure increased to the required level before entering the Hotbox.
The super heated steam of the system allows it to remove the staining & growth from the building. The steam/super heated 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.
During the stone cleaning works we also noted all areas of the building that required repair work or that would require stone work repair in the future. However we did not conduct any stonework repair as part of this contract.
The client also asked us to undertake some stone cleaning works to the Accrington Market Hall. This Listed building had become “dirty” over time. Again we used the “DOFF” cleaning system to clean the stone work.
The stone surfaces of the market Hall had heavy deposits of soot and carbon, so we used additional chemical cleaning that “Bleaches” the stone back to its original colour. This stone cleaning technique will not damage the stone in any way but does require additional water to rinse off the stone. Trying to remove soot and carbon deposits on stonework with Sandblasting can damage and erode the stonework further. Chemical cleaning of Stonework is very good on carved and decorative stone.