What Is Algae On A Roof (And How To Get Rid Of It)

Estimated Reading Time : 4 Min.

Share Now :

What Is Algae On A Roof (And How To Get Rid Of It)

Homeowners are taking the aesthetic appeal provided by an asphalt shingle roof more seriously than ever. Your roof now plays a crucial role in improving your home’s curb appeal. However, some things, such as dust or algae, can have a negative impact on your roof. If you notice dark streaks or lines on your roof, it may be caused by algae growth.

You might be wondering what it is and how to get rid of it so that you can get your roof back at its best. This article will give you all the information you need to know about algae growth and the best way to get rid of it from the roof of your home or business!

What Is Algae?

If we talk in a biological sense, algae is a group of simple, primitive plants that grow in water. They contain chlorophyll like other plants, but it is not as complex. Algae are common in bodies of water such as lakes, rivers, and oceans. Apart from water bodies, algae can thrive in other areas that are dark and damp.

The unsightly black streaks you see on your roof are caused by the water-borne algae. The creatures are called Gloeocapsa magma, commonly known as blue-green algae. We discuss this more in the following section.

What Is Algae On The Roof?

A simple type of bacteria, blue-green algae thrives in dark and shady areas with abundant heat and moisture. When rainfall occurs in the area, or when weather conditions start getting humid, they can also grow on your asphalt shingles. The reason for this is that asphalt shingles are not made from asphalt alone. Other materials such as fiberglass, limestone, and minerals also make shingles.

The roof algae feed on the limestone fillers present in the majority of the shingles. These act as nutrients that allow them to grow and damage your roof. They appear as black streaks as the algae develop a dark coating to protect them from the sun’s (UV) rays.

Algae On Roof

How Does Algae Reach My Roof?

Algae is a fast-moving organism that can spread rapidly with the help of the wind. Birds and animals can carry the algae spores on the roof, where they can feed on the lime coating and grow.

Is Algae Harmful For Your Roof?

Many homeowners are concerned about how this algae or other fungus can damage their roofs. Until now, there has been no evidence that they will hamper the ability of your roof to function. However, they can cause harm to the look of your asphalt shingle roof. Starting as patches, they can cause discoloration of the entire roof. The black streaks will not make a good impression on your home. The black lines on the top of the roof will drastically reduce your home’s curb appeal and value. Also, the little spores can travel and damage the other areas of your home.

How To Get Rid Of Algae On Roof?

You do not want your roof to have a dirty or damaged look. This is why if you find that blue-green algae have occupied your roof, it is important to start getting rid of the algae as quickly as possible. If most of the shingles are damaged, and your roof is past its lifespan, you might think about replacing your roof with better shingles. 

However, there are other options as well. At Kickapoo Roofing, we receive a lot of questions regarding how to remove the black streaks from the roof. Our experts with years of experience share how you can clean your roof.

Use Bleach To Clean The Shingles

One of the most effective and cost-friendly ways to remove moss, mildew, and algae from your roof is with the help of bleach. It is a powerful solution that combines water with sodium hypochlorite. Bleach is known to kill many bacterias, fungi, etc., and it can help remove stains. Here are a few steps to use bleach for the roof.

  • You can start by mixing bleach and water to create a solution. You can mix them together in a spray bottle.
  • Mix one part bleach with one part water in a bucket or sprayer (50:50 ratio) and spray all of the algae-covered areas on your roof and let it sit for 20 minutes.
  • Use a scrub brush to remove any visible algae from the roof’s surface.
  • You’ll likely see some stains left behind by the bleach, but don’t worry—you can easily remove these by using a garden hose.

A Helpful Tip To Clean Your Shingles

When cleaning off algae with scrub brush, be careful not to damage the shingles underneath! This can result in leaks when it rains and can cause rusting or rotting of the wooden frame inside your home. Also, don’t use bleach without diluting it on your roof because it can damage tiles and other materials used inside homes that are exposed to the sun for long periods. Remember not to use a power washer when cleaning your roof, as these can also damage the shingles.

How To Prevent Algae On Your Roof?

Your responsibility does not end after cleaning the roof. As you may have heard, prevention is better than cure! Therefore, you need to ensure that the algae does not return to your home’s roof anytime soon.

  • The best way to prevent algae is to ensure the roof stays dry, clean and free from debris.
  • Trim the trees surrounding your property whose branches extend and reach your roof to let in sunlight.
  • Install high-quality asphalt shingles that leading manufacturers make for better protection of your roof.

Get The Best Asphalt Shingle Services In Wisconsin

If you want to install the best asphalt shingles in the Wisconsin area, then look no further than the team of Kickapoo Roofing. We install GAF shingles. These asphalt shingles by GAF are one of the best in the market, and they come with StainGuard Plus technology that resists algae growth and comes with effective warranties.

We also offer exceptional roof repair and replacement services to ensure your roof stays at its best for a long time. Contact us today to get started on the process early

Skip to content