close up of algae and moss growing on rooftop

How to Get Algae Off My Roof

Bondoc Team

Posted By: Bondoc Team

Posted Date


If you are wondering “how to get algae off my roof,” you are far from alone. The unsightly mess affects many homes in San Antonio, TX, and the surrounding areas. 

You might find yourself dealing with other types of growth like moss as well. 

In any case, you need to understand what is causing the growth and what your options are for handling it.

What Is Roof Algae?

Algae is most often what you think of when you see the green buildup in fish tanks or natural bodies of water. In fact, algae covers a wide range of different types of growth, and certain types will consider your roof a suitable home.

Roof algae is most common in areas that are warm and have high humidity, much like San Antonio, TX. It shows up most often as black streaks on your roof that can be very unsightly. The algae is dark in color to protect against ultraviolet light, and that helps it survive and thrive on your roof.

If you are up to date with your roof maintenance, you might be able to catch algae early in its life cycle. The patches will start out as small circles before eventually spreading into the longer streaks. Most people do not notice until there is already considerable growth, which will be a few months after the algae takes hold.

Algae spreads by releasing spores that are distributed by the wind. This means that algae growth is likely to affect entire neighborhoods at once. If you notice roofs with signs of algae around your block, it could be the best time to act quickly and deal with the issue preemptively for your own roof.

Why You Should Deal with Algae Promptly

Though it is unpleasant to look at, for the most part, algae is not a major threat to your roof and does not damage asphalt shingles. However, moss and other growth can cause damage when their roots penetrate your shingles. (Algae does not have roots.)

One scenario where algae can damage your roof is if you have a light-colored or highly reflective roof. Metal roofing, in particular, is susceptible to developing issues with algae. The dark algae makes your roof absorb more light, causing it to heat up more than usual.

If you do not want algae to become an issue for your roof, the best course of action is to act quickly as soon as you see it. Reach out to a local professional to provide cleaning and take care of the issue for good. Having scheduled roof maintenance can help spot algae early on, and will make the removal that much easier.

Health Risks Associated with Algae

Algae and moss can weaken your roof’s structure by forcing it to absorb more light than it normally would. But there are other risks associated with algae growth that homeowners must be aware of. 

Though it’s rare, algae can cause sickness and disease in humans and animals when inhaled, consumed, or otherwise contacted. 

While homeowners may think they’re safe because algae growth is on the roof, algae spores travel in the wind. If you have excess algae on your roof, spores can blow from your roof and onto your property and contaminate your water. 

Routine exposure to heavy amounts of algae can lead to:

  • Respiratory irritation
  • Allergic reactions
  • Nausea
  • Vomiting
  • Eye irritation
  • Skin rashes
  • And more 

Of course, if your San Antonio, TX, roof only contains a small amount of algae growth, the likelihood of contracting some physical ailment is relatively low. Still, it’s important to note that excess algae does contain inherent dangers and is not as benign as you may think it is. 

Call a nearby roofing company like Bondoc Roofing for regular roof maintenance and keep your roof algae-free! 

Preventing Algae and Other Growth on Your Roof

If you are already searching for “how to get algae off my roof,” then chances are you will want to know how to prevent it from coming back once it is gone. After you have had professionals deal with your current algae issue, you can take a few simple steps to prevent the same problem from happening again.

In most cases, algae and moss will grow in areas that receive partial sunlight. If you have tree branches hanging over your roof, they could be providing an excellent environment for this growth. Trimming them back and ensuring that other debris is not creating shaded areas can help.

Gutters are another thing that should be kept in working order to prevent algae growth and other issues with your roof. If your gutters become clogged, they could provide a reliable source of moisture for algae and other growth. They may also allow water to pool on your roof, which could cause much more serious water damage.

Some roofing materials are available with algae-resistant properties. These can prevent algae and moss from growing on your roof. Most of them incorporate zinc or copper strips or copper granules. Copper is highly toxic to algae and moss growth, and copper sulfate is widely used as a professional cleaning product for treating algae.

The best prevention is to have a regular roof maintenance plan in place. This can include annual inspections to check for algae growth along with a variety of other common roof issues, including:

  • Missing or damaged shingles
  • Cracked or peeling seals
  • Damaged flashing
  • Leaks
  • Sagging
  • Signs of rot and other water damage

Whether you need to deal with algae growth or not, a thorough roof inspection from a local professional is an effective way to get ahead of any potential issues.

Tree Trimming

It’s impossible to discuss roof maintenance without addressing tree trimming and care. Oftentimes, San Antonio, TX, homes are bordered by vast, towering oak trees. While these trees may be majestic to look at, they can present a serious hurdle in maintaining your roof and preventing excess algae growth.

Multiple studies have concluded that algae are more likely to thrive in areas that contain both sunlight and shade. When large, luscious tree branches hang over our homes, they cast long shadows, crafting an oasis for algae growth.

Because of this, it’s important to keep an eye on our roofs to inspect for algae growth. If you notice an uptick of algae growth underneath the shadows from tree branches, it might be worth reaching out to a professional tree trimmer to cut back some of those branches.

Overgrown trees threaten the health of your roof in other ways, too. When branches extend over your roof, they frequently drop leaves. 

After a while, those leaves collect on your roof and can trap moisture on your shingles. As we know, algae demand a moist environment to spawn. Having leaf buildup, gunk, and humidity on your shingles encourages algae to form. 

Don’t let your beautiful trees throw a wrench in your roof’s health and safety: call a nearby roofing company to assess and trim your trees today. 

Gutter Add-Ons and Other Protective Measures 

One significant reason for algae and mold buildup is excess humidity and moisture. Rain is a normal part of San Antonio, TX; the trick is allowing the rain to pass off your roof freely and not get backed up by leaves and debris. 

That’s where your gutters come in. To ensure that your gutters are always clear, you can purchase add-on tools like gutter guards to prevent debris from clogging up your gutters.

Professional Roof Inspections

Sometimes it can be hard to detect algae on your roof since it’s usually out of view. Short of scaling a ladder and inspecting a roof up close, algae growth is easy to miss.

That’s why scheduling annual professional roof inspections are so important. During a roof inspection, a highly-trained roofer will check your roof for any structural insecurities, damages, weak spots, mold, moss, or algae growth. 

Allowing a technician to inspect your roof will give you a heads-up on any algae growth and give you time to get it removed before it overtakes your roof. 

The Dangers of Amateur Algae Removal 

Once you notice algae growth on your roof, it’s difficult to unsee it. Some homeowners find it tempting to break out that ladder, roll up their sleeves, and scrub the algae away themselves. 

However, attempting to remove algae without a professional is highly dangerous. A professional will have the experience and proper tools to safely navigate your roof. You risk falling off your roof and maiming, injuring, or even killing yourself without those tools. 

Furthermore, professional roof cleaners have powerful, effective chemicals to remove algae. On the other hand, DIY algae-removal concoctions (like bleach) can disintegrate your shingles and cause roof leaks. 

Lastly, if you try to remove algae yourself, you risk trapping even more moisture underneath your shingles, exacerbating the problem.

For effective algae removal, contact a professional algae removal service. 

Professional Roof Maintenance in San Antonio, TX

Do you have algae or moss growth on your roof? The best way to handle it is to reach out to the professionals at Bondoc Roofing for reliable and effective roof maintenance. 

With roofing experience going back for generations, Bondoc Roofing is a family-owned business that is proud to deliver excellent roofing services here in San Antonio, TX

Just give us a call today to find out what we can do for you.

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