My building has been cleaned several times and it still does not look clean. There are white marks, the mortar has yellow streaks and the base of the wall looks very bad.
The problem that you have described is very common to a wall that has been cleaned improperly. The white marks are probably pressure washer marks. Too much pressure or the use of the wrong tip can damage both brick and mortar. The yellow streaks are usually caused by not properly rinsing, not properly prewetting or by starting at the top of the wall instead of the bottom. The base of the wall sounds like they did not protect the wall when the sidewalk was poured which allowed concrete to splatter on wall.

Our recommendation to correct this situation is to reclean the wall with PROSOCO SUREKLEAN 600 Detergent at a dilution rate of 1 part cleaner to 5 parts water. Clean smaller areas at a time and use plenty of water when prewetting and rinsing. Clean bottom to top and use a pressure washer with no more than 1000 lbs. of pressure and a forty degree fan tip nozzle staying at least 12 inches from wall. Always do small test panel and adhere to all manufacturers recommendations.

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