General Exterior Facade Chemical Cleaning Specifications
Brick, Granite or Sandstone Cleaning
Always follow the manufacturer's recommendations. Many cleaning solutions are concentrates so it is imperative that a small patch test be conducted. Certain types of brick require the product to be cut with up to three parts water. The only way to determine the best mixture is to conduct patch tests on the substrate to be cleaned. After rinsing the patches, allow them to dry thoroughly and observe...|
A. the cleanliness of the patch and
B. any discoloration or whitening of the stone.
Whitening indicates the cleaner is too strong and must be cut with water.
Apply the product by brush, spray or roller. Start at the bottom of the structure and apply an even coating. After a dwell time of twenty to thirty minutes, rinse the product off with a high pressure rinse. Experience indicates that best results will be obtained if the product is sprayed on at 30 PSI (2 BAR) and rinsed with a 5 GPM nozzle at 1500 PSI (19 Litres/Min. at 103 BAR). Under certain conditions, such as extreme friability of the stone, the rinsing pressure can be reduced. It is extremely important however, that all of the chemical be thoroughly rinsed from the substrate, leaving the surface with a neutral pH.
Treatment of contaminants such as iron oxides (rust) copper stains, graffiti or the removal of sealants may require the use of compatible products or a second application of the base product. Exact procedures can be determined by reviewing the manufacturer's literature or by consulting with the manufacturer's representative.
Many brick cleaners contain a small percentage of Fluoride necessary to clean the silicon oxides in the brick, granite or masonry. Since the possibility of etching glass does exist, particularly soft plate glass, it is recommended that glass windows, doors and anodized aluminum be masked with polyethylene sheeting. Brick, granite and sandstone cleaners should not be sprayed on very windy days as they could be deposited on unmasked glass.
The manufacturer has developed his cleaning systems to perform certain predetermined tasks. Any deviation from the prescribed methods and procedures may compromise the end results.