Throughout a roof’s normal lifespan, a mess of leaves and accumulated dirt are two of the most common things that a roof usually has on its surface. After decades of use, there is one more notable thing can grow on your roof’s surface: algae.

Depending on the weather conditions, the location of your home, and other factors that can be found in the surrounding environment, different types of algae, fungi, and lichens can develop on your roof over time. The most common type of growth that spawns up on roofs, however, is blue-green algae, which often leaves hard-to-clean dark streaks on the surface of your roof when it dies. Not to be confused with roof mold, algae can cause even more trouble for the appearance of your roof’s surface if left unattended over a certain period of time (usually a year).

In order to better understand roof algae and discover the solution to fixing it, here are a few facts and steps that you need to know and take in order to handle the blue-green visitor in the best way possible:

Recognizing roof algae
One of the most common problems that people encounter with roof algae is that they don’t even know what it looks like in the first place. Most types of algae are distinguishable through their trademark discolored finish and odd appearance overall; aside from discoloration, certain types of algae can also be recognized through certain types of stands, streaks, or even a blanket of green, mossy growth. In some cases, algae can also look like mold that typically looks like the growth you get on bread after leaving it out for a while. Here are some distinct characteristics you need to watch out for when spotting roof algae:

● Black Streaks
● Green or white spots
● Round lichens
● Mosses

Should roof algae be left unaddressed, it can travel and grow in your home’s roofing materials. This is particularly true when a pool of water containing the algae gets trapped in a certain area. Under the right conditions, algae can cover up your entire roof in around four years or less. This can be avoided if your contact a professional roofing contractor in your area to inspect the situation.

Understanding what causes roof algae
To prevent roof algae, it’s important to understand what actually causes it in the first place. Due to humid atmospheres, an abundance of shade, and the presence of certain types of “algae food” in your roofing materials, roof algae grows much easier in most modern homes. Typically, the reason why algae ends up in your home is described as a chain reaction mixed with a snowball effect because a single algae spore ending up on your roof from the wind or the rain and can start the whole process of algae taking over.

Certain factors, such as clogged gutters, standing water, overhanging branches, poor roof ventilation, and porous roofing material can also cause algae to sprout up, and the inorganic materials found in the composition of your roofing can allow it to thrive as best as possible.