Stover wanted the building as you face the entrance cleaned after years of being left
Stover school have a Portland Stone Portico that is part of the sites listed status. The Stone is limestone which is soft and chemicals could not be used
Pressure washing risked damaging the stone and mortar and had been used relatively unsuccessfully
Both Red and Black algae were in evidence on the front elevation
Lichen was wide spread across the structure
Many of the stains looked like carbon but on testing were actually black algae
Other companies had suggested using poultices to remove the staining (maybe mistaking the black patches for carbon rather than algae) which would have cost the school excessive amounts due to the intensive labour and materials involved and was unnecessary
Access would be needed for considerable amounts of the structure at 6 m high for long periods of time
The Solutions
We advised use of our market leading stone cleaning machine. The Doff, from Stonehealth
We used an aluminium tower in order to access heights
We completed a conservation clean which will help both maintain the stone by allowing it to breathe and also maintain the spectacular appearance of the natural stone for years to comes
The Result
We at Totex and the customer, Stover School, were absolutely delighted with the results. The portland stone cleaning has left the portico literally shining in the sunlight
There are no longer any signs of biofilm or lichen to the front of the structure and the façade has been restored to its original light colour
