If you notice black streaks or stains on your shingled roof, you may wonder if they're dangerous or unsafe. The stains covering your roof may be algae. Although algae isn't particularly damaging to your shingles, the plant can interfere with your roof's appearance and reduce the value of your home over time. But with the right information and precautions, you can make your roof algae-free again.
Why Does Algae Grow on Roofs?
The "black" algae on your roof is actually blue-green to green in color instead of black. The algae also requires moisture to thrive. Although roof algae grows best in shady locations, it can survive locations with some sunlight. The plant does this by creating a dark, UV-protective "barrier" or sheath around it. The sheath also gives the algae its black appearance.
A number of things can introduce algae to your roof, including overhanging tree limbs and birds. These things drop spores of algae on your roof's surface. The wind can also carry algae spores to your roof. Once it rains, the spores on your shingles take hold and grow.
Algae can take months to develop into the large dark streaks you currently see on your roof. When algae begins to show up on your roof, it may look similar to small dark spots. If you do notice the spots, you might blame it on animal feces, dirt, or even black mold.
As mentioned above, algae doesn't truly damage the integrity and safety of your roof. However, the plant can potentially hinder your home's overall appeal. In this case, you can take steps to remove the algae and keep it off.
How Do You Remove Your Roof's Algae?
One of the things you can do is have a roofing contractor remove the algae from your shingles. Although it's possible for you to power-wash your shingles, it's a good idea that you avoid doing so. Power-washing can damage your shingles, or it can remove the granules from them. Without granules, your shingles lose their ability to protect your roof from harmful ultraviolet light. If your shingles become too damaged by heat, rain and other moisture can potentially leak into the home, which causes additional problems for you.
Roofers may use a mixture of bleach and water to remove the algae, or the contractors may choose to use chemicals especially designed to kill algae plants. Algae-killing treatments may keep the plant from taking up residence on your roof. Contractors can go over your options before they begin the job.
If the algae on your roof is significant, you may need to replace your shingles altogether. Sometimes algae can be difficult to remove once it takes over a roof. In this case, it may be better to replace the compromised shingles with new shingles. Some roofers offer algae-resistant shingles made with copper as replacements, but these types of shingles require water to work properly.
Once your roof is free of algae, you can do a few things to keep it that way. If trees grow over or close to your home, you may want to trim them to control the algae on your property. Even if you use algae-resistant shingles, algae can still grow on your siding, gutters, and other unprotected structures. Taking precautions now can save you headaches later.
Finally, schedule routine maintenance of your roof each year or as stated by your roofer. A contractor from a place like A & A Roofing Company Inc can monitor your roof for any signs of problems and make the best recommendations to repair them, including missing or damaged shingles.
If you have concerns about the black stains and streaks on your roof, contact a roof repair contractor today.