Get matched with top chimney sweeps in Saint Elmo, IL

Other than it looking like a dirty car, there are some other signs you need to clean your roof. Moss growth, algae (often black streaks), grime buildup, buildup under shingles, and leaf buildup are all classic signs a cleaning is overdue. If you have neighbors, take a look around. If your roof appears different in any way, that’s another sign to call a pro to have it cleaned.

You may become so frustrated with the look of moss on your roof that you contemplate whether to clean or replace your roof. Fortunately, you don’t have to go as far as replacing it. After cleaning the moss, you can use a chemical solution to keep it away. For further protection, trim branches that overhang the roof, as fallen seed pods and leaves on the roof allow moisture to collect, encouraging moss growth. Consider adding zinc-coated flashing to the roof, too. As rain washes across the zinc, it leaves zinc particles behind that inhibit moss growth.

It may require stronger cleansers or chemicals, higher-pressure spray, or scrubbing to completely remove algae from a metal roof. Start with a mild cleanser; if that doesn’t work and you're comfortable doing so, use a stronger mix of ⅓ cup of laundry detergent, 1 quart of bleach, and 3 quarts of water to gently scrub the algae with a soft-bristled brush. If algae is present across large portions of your roof, doesn’t come off with gentle scrubbing and cleansers, or is in hard-to-reach areas, this may be a job better left to a pro.

A green roof is a roof design that includes a thin layer of vegetation on the roof surface. It’s an environmentally friendly option. Some green roofs may look like they have moss or algae on them, causing neighbors to suggest that you clean the roof. However, you should never try to clean a green roof, as any cleaning methods you deploy will likely kill the vegetation.