Standing seam metal roofs are known for their durability and sleek appearance, but they can sometimes develop algae or moss growth, especially in damp, shaded, or humid environments. Algae often appears as dark streaks or stains, while moss looks like small patches of green, fuzzy growth. These organisms typically thrive where moisture lingers longer than usual, such as shaded areas or where debris accumulates. While metal roofs resist moisture penetration, algae and moss can still cling to their surface, affecting aesthetics and potentially causing surface corrosion over time. Diagnosing the problem is straightforward: simply inspect your roof for discoloration or fuzzy green patches after periods of rain or heavy dew. A safe way to check is from the ground or a sturdy ladder—never climb your roof without appropriate safety gear.
To address algae or moss on a standing seam metal roof, gentle cleaning is usually effective. A solution of water and mild detergent or a specialized algae cleaner can be applied with a soft brush or low-pressure hose to avoid damaging the protective coating. Avoid abrasive tools or harsh chemicals that might void your roof warranty or harm the metal finish. Routine maintenance helps keep these growths in check, but if the problem persists or the roof has visible damage or corrosion, it’s wise to call a professional roofer. When hiring a contractor, consider asking: “What cleaning methods do you use that won’t invalidate the manufacturer’s warranty?” and “How do you prevent damage to the metal and seams while removing algae or moss?” These questions ensure your roof is treated properly and keeps performing well over its expected lifespan.