Masonry Magazine August 2001 Page. 14
After
President U.S. Grant's home in Galena, IL was restored using a new citrus-based cleaner from Diedrich Technologies.
14 MASONRY AUGUST, 2001
Before
ditional drawback: if the surface is not pressure-washed afterward, the bicarbonate becomes imbedded in the surface. Whenever the surface gets wet, the bicarbonate residue will bloom and simulate efflorescence or a white fuzz growing on the structure. According to Building Renovation Magazine (September 1995), "this system is an example of new technologies gone awry."
Over-cleaning and damage to the masonry being cleaned will occur because, when holding a heavy sand-blaster-type hose and nozzle, worker fatigue is rapid and indiscriminate etching will result. In all abrasive systems this fatigue causes uncontrollable time spent on these surfaces. What appeared good and easy to accomplish in the small sample demonstration, is understandably difficult to quality control as cleaning movements by workers result in visible etching patterns from their to and fro motions. Because of the controversy of this so-called gentle technique, the city of Chicago was asked by the landmarks agency to cease this method of cleaning.
Finally, there is the pelletized carbon dioxide cleaning method. This system uses pressurized air to apply pellets of carbon dioxide to the surface to be cleaned. While these above-men-