Torch-down roofing is a type of flat roof system commonly used on low-slope roofs, featuring layers of modified bitumen that are heated with a torch to seal the seams. This roofing style is durable, but like any roof, it can become vulnerable to algae and moss growth, especially in humid or shaded areas where moisture lingers. Algae appears as dark streaks or stains, while moss tends to form thicker, spongy green patches. These growths happen because the roof surface holds moisture, sometimes trapped by debris or shading, creating a perfect environment for organisms to thrive. Over time, moss can lift shingles or the flat membrane, causing damage and potential leaks if left unchecked. Simple DIY checks involve inspecting your roof after rainfall or in shaded spots to see if you notice persistent black streaks or green clumps. You can carefully clean mild algae with a gentle soft brush and a mix of water and mild detergent, avoiding harsh chemicals that might void warranty or damage torch-down layers.
While occasional algae may not severely impact your roof’s function, significant moss growth or persistent moisture issues should prompt a call to a professional roofer. A contractor can offer safe cleaning options, inspect for membrane damage, and suggest preventive measures like zinc or copper strips that reduce organic growth. When consulting a roofer, ask specifically if their cleaning method is safe for torch-down roofing and whether it affects your warranty. Another good question is how they recommend improving drainage or sunlight exposure to minimize future moss or algae buildup, as proper maintenance is key to prolonging your roof’s lifespan. Ensuring a roof is inspected regularly and kept free of moisture-holding debris helps maintain both its appearance and integrity.