Metaclear: The gel is sprayed or brush applied. It has good adhesion. After a few minutes the gel stops working : It needs agitating. This will renew the active interface and collect removed contaminants. After a few minutes of second dwell time the render is rinsed.
The intensity of the gel treatment depends on the amount of metabolite to remove. A thin grey layer may only need coating and one dwell time before rinsing. If the grey is deeper, the gel will need agitating as above. If the black marks are long established the process is repeated.
Metaclear & steam: Steam is often used to remove thick layers of metabolites where excessive amounts of chemical would otherwise be needed. When the wall is substantially free from growth the finishing will consist of an application of Metaclear, eventually brushing after dwell time and steamed off. The flash application of heat on the gel provides the flash of detergency to the process.
Metaclear and pressure water. There is a risk inherent to applying pressure on a thin render particularly if there is insulation behind. For this reason we avoid it on render. However : With precautions a thin blade of pressure water will achieve good results in removing the bulk of a metabolite covering or lichen from stone. Ceramic nozzles will give a thinner water blade and the pressure reduced to about 15 bar, thus reducing the risk of damaging the substrate.
Red brown marks: They are usually clearly identified as rust marks and an acidic contact is the only chemistry available. Oxiclear is formulated for safe application on render. It is a gel preventing the acid from permeating the porous and alkali substrate. Care should be taken to monitor the dwell time. If left too long the gel may leave a slight colour difference with the rest of the elevation.
Tanin marks: They are not very common, but always delicate to remove. We find them below Cedar cladding, balcony decking, oak structures etc. After a gentle brushing with Oleoclear to remove ready soluble compounds Oozeclear will interact with the iron in the tanin and transform it into a soluble compound. The surface becomes bright pink during the iron conversion and needs re-applying until completion and rinsing. Oozeclear is very pungent and works most of the time.