The answer to 'retaining wall brown patches' is that brown patches on a retaining wall are often caused by water damage, mold, or poor drainage. These patches can be unsightly and may indicate a larger issue with the wall's structural integrity.
Some common causes include excessive moisture buildup, poor drainage around the wall, and exposure to the elements over time. Symptoms may include discoloration, crumbling mortar, and even cracks in the wall itself. To address these issues, it's important to identify the root cause and take appropriate action.