WGL Stone Clean
Types of cleaning methods employed by WGL Stoneclean include: Detergent/Water Cleaning
For lightly stained Portland Stone Facades water cleaning only Nebulous Technique is often sufficient. For other lightly soiled exteriors, a specialised form of detergent is sprayed onto the building at low pressure. The detergent is then washed from the surface using high-pressure jets of cold water. In certain circumstances we will use hot water at high pressure to complement the cleaning action of the detergent for rinsing. Detergent techniques are invariably used on artificial stone (artstone) facades. Our level of experience ensures that only the required amount of dirt is removed leaving the masonry fabric undamaged, yet perfectly clean. Acid Washing
For heavily soiled exteriors. Here the WGL Stoneclean surveyors and operatives will decide upon the correct type and concentration of acid to be used. Very often small trial areas will be cleaned to check the concentration required. This choice is dependant on the sort of masonry used on your property and the amount and depth of soiling. As WGL Stoneclean carry out their own acid dilution, concentrations are easily adapted to the degree of staining. In the last three years, WGL Stoneclean has pioneered the use of using a super-heated steam wash-off after acid spraying. With this technique acid dilutions are significantly reduced and dwell times can be reduced to seconds. Acid cleaning is not very aggressive when applied to brick or stone surfaces. The solution only attacks the top one or two grains of the surface allowing the water/steam jet to penetrate into the surface and remove the small carbon deposits. For the technically minded, if the average grain size of the stone is 2-500 microns and the stone thickness is 23cm, then over an average building life of 100 years, acid cleaning will reduce the building life by 2.6 months! Using this unique acid wash WGL Stoneclean will produce clean old buildings with the mineral salt colourings of the natural stone readily visible over many decades of air borne industrial pollution. WGL Stoneclean operatives will firstly protect glazing and other external features with heavy duty polythene film and masking tape or a brushable, peelable PVC film, which is both water and acid proof. This acid solution is applied by a low pressure sprayer onto the surface of your property ensuring that none is splashed onto surrounding features. After the solution has been left for a pre-determined time – the acid and the soiling are sprayed off with jets of super-heated steam at 150 degrees centigrade at a pressure of 150 to 170 bar. Because high volumes of water are used, the residual acid solution is extremely weak and therefore safe. We have successfully cleaned buildings immediately adjacent to water course with no water borne acid contamination.