The answer to 'patio installation turning brown' is that the discoloration is likely due to a buildup of organic matter, mold, or mildew on the patio surface. This can happen over time as dirt, debris, and moisture accumulate on the patio. The brown or discolored appearance is a common symptom of this issue.
There are a few potential solutions, depending on the severity of the problem. For light discoloration, you may be able to clean the patio yourself using a mild detergent and a scrub brush. For more severe cases, you may need to use a specialized patio cleaner or hire a professional pressure washing service to deep clean the surface and remove any built-up grime or stains.