In the process of cleaning buildings we often have grey to black marks: The substance itself is metabolised by a fungi living in the porosity of the masonry substrate for the purpose of filtering light. It is a natural melamine. It is water soluble and further loses cohesion by photolyse – the influence of UV light. Metabolites are not alive and therefore out of scope for a biocide.
On a roof there is enough UV and water to predictably remove the black tile discolouration within a few weeks. The self cleansing process of black metabolites on concrete tiles is substantially complete in approximately 3 months after treatment with the biocide. This appears to be the time it takes the hyphae to metabolise enough carbon from the substrate to form a new opaque film of black melamine.
Cleaning Service North West Ltd
On walls the black marks do not self clean: The Algoclear Cleaning Process requires use of a gel containing Sodium hypochlorite to dissolve them in a controlled manner. Black metabolites are removed with Metaclear.
MetaClear is a high adhesion gel of sufficient viscosity to stay where applied on vertical surfaces.
It does not penetrate render porosity and is active where needed – at the surface.
The gel prevents evaporation. This in turn stabilises the active surface concentration throughout the process and prevents odorant fumes.
It provides dwell time. This in turn gives a new flexibility in the sequencing of the works, particularly when applying from an aerial platform.
The gel lubricates the surface when brushed, limiting the risk of scuffing a fragile surface and provides detergency.
It has low odour and rinses readily.