How Algae, Mold And Moss Can Affect Your Roof

Did you know that algae, mold, moss, and mildew can cause your roof to rot? It’s true, which is why it’s so important to have biannual roof inspections done by Softwash Hawaii to ensure none of these fungi are forming on your roof or hiding in areas within your roofing system.


Having mold, mildew, moss, or algae growing on your roof is more than just an unsightly nuisance that brings down the value of your property. Each can cause roof rot and lead to health problems for people living in the home or residential complex, or for workers in a commercial building. Let’s take a closer look at each of these culprits.

Algae: They like dampness and shade, so algae spores can grow on wood shingles or shakes and asphalt shingles that don’t get much sunlight. Because roof algae retain moisture, they can cause shingles to deteriorate and eventually rot completely. Algae also like the humid conditions in gutters and downspouts and can grow there as well. Algae are recognizable by their black-green coloring.


It likes moisture, so it typically grows on moist wood shingles or shakes. As the moss grows, it contains even more moisture, all resting on the surface of your roof. Eventually, your roofing materials begin to rot, compromising the integrity of your roof.


Appearing as fuzzy black, brown, or green spots or slimy film, mold is attracted to damp or humid environments and spreads quickly. Black mold is the most dangerous type of mold. It lives on wood, paper and drywall, so if the problem is not addressed quickly, it could weaken the entire structure of a home or building. Easily recognizable by its dark black color and its strong musty smell, black mold is toxic and can cause serious respiratory illnesses in occupants of the home or building.


Recognized by its powdery consistency, mildew typically grows in warm, humid and rainy environments. It is most commonly found on roofs with poor drainage or where trees hang over the roof line. Green, black, red, or pink in color, mildew is a fast spreader.


Mold, mildew, moss, and algae spores exist in the air, but they won’t start growing on your roof if the right living environment isn’t there. The best way to spot and treat roof mold and mildew and roof moss and algae problems before they grow out of control is through biannual roof inspections. Contact Softwash Hawaii to schedule your inspection today.

Often times, roof fungus can enter a home through a hidden roof leak. Water draining off the roof seeps into the interior of a structure, creating an environment where black mold or mildew can form. Only a professional roofing inspection will reveal this problem.

There are also some preventive measures homeowners and commercial property owners can do to safeguard their roofing systems from fungus. Here are some tips:

  • Trim away any trees touching your roof to prevent algae from growing.
  • Keep your gutters clean so moisture properly drains through them, preventing moss, mold and mildew.
  • If you live in weather conditions that foster algae, mold, mildew and moss growth, consider paying more for roofing materials or techniques that resist their growth. It will be worth the few extra dollars in the long run.
  • Improve your ventilation inside and out. For your roof, ridge vents provide the utmost aeration. Contact us for more information about roof ridge vents.

Proper care and maintenance is essential for the long-term performance of your roof. A roof inspection, especially after a storm, is a major component to proper roof maintenance. 

With our biannual roof inspections and storm damage inspections, you can rest easy knowing you’re doing all you can to prevent your roof from becoming a host for fungus and other harmful organic substances.

Contact Softwash Hawaii at 808-352-8885, email at, or to Learn More, visit

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