Unsightly black streaks caused by unchecked algae growth can make your asphalt roof look old well before its time. Not only does algae growth detract from your home’s curb appeal, but it also makes your roof less effective at channeling away rainwater over time. Large-scale algae growth may even lead to other, more serious issues with your roof.


Prevention is always the best policy for dealing with algae growth. The following tips can help you keep algae away from your asphalt roof.

1. Trim Back Overhanging Trees

Asphalt roofs with plenty of nearby tree cover are particularly susceptible to algae growth. Algae grows best in moist areas that are heavily shaded from sunlight. Tree branches that hang over your roof can inadvertently provide enough shade for algae to flourish. Trim back the overgrowth to expose your roof to sunlight, interrupting the algae growth cycle.


Also trim away overhanging tree growth to prevent debris from being deposited directly onto your roof. Keeping nearby trees trimmed also denies small rodents an otherwise easy path to your roof, thereby preventing roof damage commonly caused by nesting animals.


2. Keep Your Roof Debris-Free

Allowing dead leaves, branches, and other debris to accumulate on your roof can provide cover for algae growth underneath. The debris buildup also retains excess moisture, giving algae the moist, humid environment it needs to flourish.


Keep your roof clear of debris to prevent algae from gaining a foothold on your asphalt roof. You can use a roof brush or a leaf blower to carefully remove debris buildup.


3. Clean Your Gutters Regularly

Your gutters are essential for controlling water runoff that would otherwise cause damage to your roof structure. Over time, dead leaves and other debris can clog up the gutter channels, allowing water runoff to saturate the roof. The excess moisture not only spurs algae growth, but it can also cause long-term damage to asphalt shingles and other underlying parts of your roof.


To prevent moisture buildup and subsequent algae growth, you should have your gutters cleaned on a biannual basis. Installing gutter guards can also decrease the likelihood of debris buildup, which will also prevent algae growth.


4. Consider Installing Copper Strips

Copper is well known for its fungicidal properties against moss and algae, making it an environmentally friendly option for controlling algae. A set of copper strips installed along the ridge of your asphalt roof provides a protective barrier against future algae growth.


As rainfall comes into contact with the copper strips, the strips release copper ions into the water runoff. The runoff spreads the copper ions throughout the roof, providing a fungicidal coating that prevents algae growth from taking place. Unlike anti-fungal treatments that wear off over time, copper strips are a permanent solution that works as long as there’s sufficient rainfall available.


5. Invest in Algae-Resistant Shingles

The next time your asphalt roof needs replacement, you can ask your roofing contractor to use algae resistant shingles. These shingles have the same outward appearance as ordinary asphalt shingles, meaning they won’t negatively impact the aesthetics of your home. The main difference lies in the copper granules embedded throughout each shingle.


Like copper strips, the copper granules embedded within algae-resistant shingles need rainfall to provide effective fungicidal coverage for your roof. One benefit of having copper granules embedded in every shingle is that you’ll get guaranteed coverage of your entire roof, whereas copper strips may fall short without sufficient rainfall.


These tips can help you keep algae from taking over your asphalt roof. To learn more about preventing algae growth, don’t hesitate to contact Top Dog Roofing. Our team of professionals will gladly assist in protecting your roof against algae and other hazards.​