If you've noticed dark green or black spots on your roof, you may be dealing with an algae problem. Algae is a plant-like organism that grows in moist environments, and roofs provide ideal conditions for algal growth.
The question is, does algae damage roof shingles or is it just an aesthetic issue? Algae itself does not directly damage most roofing materials, but over time, excessive algal growth can accelerate degradation and deterioration by trapping moisture against roof surfaces. So while the algae alone is not immediately damaging, the moisture retention and staining caused by algal growth can contribute to roof damage long-term if the growth is not controlled.
Several factors contribute to algal growth on roofs:
The algae itself does not directly damage asphalt or composite shingle roofs if not removed from the roof. However, over time algae can contribute to the degradation of the roof in a few ways:
So while algae alone will not directly cause leaks or roof failure, if left unchecked it can accelerate normal weathering and degradation of shingles.
Algae is less likely to damage other roof types like metal, tile, or slate. However, if the growth is extensive, it can still cause problems:
So while algae itself won't compromise the integrity of these materials, heavy growth can contribute to moisture issues that speed up deterioration over time.
If your roof is suffering from an algae problem, here are some ways to remove and control it:
The key to controlling roof algae long term is limiting moisture. Here are some tips:
Following good roof maintenance practices is the best way to stop algae in its tracks and keep your shingles looking their best.
While algae alone won't cause immediate roof failure, extensive growth over time can accelerate wear and tear on asphalt and composite shingle roofs. Keeping your roof clean, dry, and well-ventilated is key to preventing algae from taking hold and potentially contributing to costly roof damage down the road. With proper maintenance and cleaning, algae doesn't have to be a roof's worst enemy.
About Largo Pressure Washing Services
With over 20 years of experience, you can count on Largo Pressure Washing Services to clean your home and business exteriors right the first time. The team uses a combination of truck-mounted equipment and eco-friendly soaps for a job well done. Please call (727) 758-2424 to schedule an appointment.
Should you clean algae off roof?
Algae should be cleaned off roofs to prevent long-term damage. Although algae alone won't directly cause leaks or failure, over time it can accelerate wear by trapping moisture against shingles. Thick layers of algae can also clog gutters and drains, leading to other moisture issues. Using pressure washing, bleach solutions, algaecides or other cleaning methods can remove algae and prevent continued growth that could eventually contribute to roof deterioration.
Do algae stains affect the life of shingles?
Algae stains can potentially decrease the lifespan of certain roof shingles. The pigments in algae can cause dark stains on asphalt shingles, reducing their overall reflectivity. This causes the shingles to absorb more heat from the sun and leads to faster deterioration of the mineral surface layer. While algal stains alone won't directly damage shingle integrity, the increased temperatures contribute to faster weathering, granule loss, and breakdown of the protective mat over time.
How long do algae-resistant shingles last?
Algae-resistant shingles are formulated to inhibit algal growth and last just as long as standard asphalt shingles. Manufacturers claim algae resistant shingles have a useful life of 20-25 years under normal conditions when properly installed. However, just like standard asphalt shingles, factors like roof ventilation, weather, and sun exposure will determine actual lifespan. While algae resistance may help the shingles better maintain their appearance over time, it does not significantly impact the underlying durability of the shingle materials themselves.
Do Algae on roofs decrease property value?
Extensive algae growth on a roof can potentially decrease a home's property value. Algae stains result in an unattractive black discoloration that is visible from the curb. This unsightly appearance may turn off potential buyers and lower perceived home value. However, algae presence alone is unlikely to significantly impact value if it is just a cosmetic issue that can be remedied with cleaning and maintenance prior to sale. As long as the algae has not led to any major damage, its effect on value is mostly aesthetic.