Causes of surface deposits
Strongly adherent surface deposits on glass are caused by a variety of environmental, or circumstantial conditions. Most commonly, we offer specialist cleaning on the following types:
Concrete and Mortar splashes
Building operations can cause concrete and mortar to splash and harden on the installed glazing. This is almost impossible to remove through conventional means, without scratching the glass.
Where rainwater runs over green concrete, mortar, or some types of stonework onto the glazing, insoluble salts of calcium crystallize and become chemically bound to the glass surface. Normal cleaning will not remove these deposits.
A combination of soot, partially burnt vehicle fuels and airborne dust particles react with the glass surface and become chemically bonded, resulting in the typical blue haze stain.
Train braking systems release a combination of iron particles and hydraulic fluid droplets which, when combined with vehicle emissions, form a brown film on the glazing of buildings close to rail tracks.
Rainwater passing over flashings and other architectural metal elements can leave metal oxide deposits on the glass. White or grey streaks are evidence of this type of damage.
The effects of etching can be attributed to two main reactions. The first is where airborne cement from a nearby building operation combines with residual surface water on the glass and forms an insoluble film. This leads to accelerated weathering. The second is where stonework cleaning involves the use of a hydrofluoric acid, which will attack any glass it comes into contact with, leaving run marks.
Over a period of time, pollutants can cause the glass surface to become pitted and particles of dust fill these microscopic cavities. The result is an evident loss of transparency and reflectivity.
The specialist cleaning process
Any kind of deposit can be removed by using one of the REFACE chemical cleaning techniques, without damage to the glazing or surrounding surfaces. Normally a pre – treatment reagent is involved, which dissolves or softens the deposit and then a manual or mechanical finish restores the glass to its original brilliance. All REFACE cleaning products are environmentally friendly.
All types of glass can be treated, subject only to safe access. An ‘as new’ condition is always anticipated for the finished project.