Standard; Applies to the pressurized washing of exterior surfaces for maintenance and cleaning.
Ensure all wash procedures comply with all national, state, and local laws regarding wash water reclamation.
Flat Surface Concrete Wash (pressurized cleaning of flat concrete surface commercial or residential property)
- Use nozzles sized to deliver a maximum of 4000 PSI. Use a spray angle nozzle of 15 degrees or larger.
- Use only a biodegradable detergent. “Biodegradable” refers to detergent That is not harmful to humans, vegetation, or pets. “Detergent” refers to a water based solution that will kill mold and mildew as well as a good surfactant. (Surfactant: a compound that lowers the surface tension of a liquid).
- Ensure that all vehicles (including the contractor vehicle) are parked off of the concrete surface desired to be cleaned. Vehicles should be parked in a safe area and cones should be placed to alert oncoming traffic when vehicles are parked in a roadway.
- Begin by using a fan pattern soap nozzle.
- Fully saturate the desired area with detergent while minimizing the overspray on surrounding vegetation. Apply more soap to areas of leaf, berry or other organic markings.
- Allow the soap to dwell for ten (10) minutes without drying.
- Cleaning will be done by use of a surface cleaning unit. Start at one end of the desired area, working toward the other end. Begin by running the surface cleaner along one edge working long ways. Allow surface cleaner to hang over the edge of the surface being cleaned.
- Walk with the surface cleaner at an effective cleaning speed; moving as quickly as possible without leaving dirty concrete behind the surface cleaner.
- Once you have reached the end of the desired area to be cleaned, walk back the way you came ensuring that you hold the surface cleaner to the edge of the clean line just created. Do not overlap the surface cleaner to the previously made clean line.
- Upon completion of all the areas that can be done with the surface cleaner, a touch up will need to be completed with the wand (usually corners or tight spots where surface cleaner could not reach).
- Rinse the entire surface with fresh water by starting at the highest point of elevation. Surface should be rinsed thoroughly and be free of any excess water or dirt. Pay special attention to any low lying areas of the desired surface, as these are more susceptible to standing water. Rinse any surrounding areas with dirt or debris such as garage doors, houses, porches, etc.