White stains or powder on exterior brick walls, often referred to as efflorescence, can be a sign of moisture issues. This phenomenon occurs when water seeps through the brick, carrying soluble salts to the surface as it evaporates. Understanding the underlying causes, such as poor waterproofing or drainage problems, is crucial for effective remediation. Additionally, the choice of materials and maintenance practices can significantly impact the longevity and appearance of your brickwork. Curious about how to address these stains and prevent future occurrences? Ask Improvi.ai for personalized guidance!