What Are Those Ugly Dark Streaks on Your Roof and What Can You Do About Them?

Feb / 26 / 2021

There’s nothing more frustrating than spending a lot of time and money on a top-quality roof that looks great and provides unparalleled protection against the elements, only to come home one day and notice that your new shingles are covered in ugly black stains

But what are these streaks, and why do they appear? Are they just an eyesore, or can they actually damage your roof? Can you remove these stains yourself, or do you have to schedule professional San Diego roof maintenance services? 

In previous articles, we stressed the importance of regular roof maintenance and explained why roof cleaning is a must. Now we’ll explain why dark stains sometimes appear on your roof shingles and how to get rid of them. Read on to learn more. 

What causes black streaks on roof shingles?

The black streaks that sometimes appear on shingle roofs are usually caused by Gloecapsa Magma. Gloecapsa is a widespread type of algae that can appear in many moisture-rich environments. It’s especially likely to thrive on roofs that get a lot of shade and dew, or are otherwise located in humid climates. 

The first algae streaks typically show up on the north-facing side of a roof, as this is the side that gets less light. They can also be found in areas with considerable tree coverage. Since algae spreads by releasing airborne spores, there’s a chance that every roof in the neighborhood will soon be sporting the same unsightly black streaks

In addition to making your roof look worse and hurting the curb appeal of your property (and therefore its value on the real estate market), the moisture inside the algae can also damage your shingles over time. For this reason, it’s best to remove the algae as soon as possible. 

How do I get stains off my roof?

If the algae keeps reappearing on your roof despite regular washing, consider replacing your shingles with mold and algae-resistant roof shingles. Another option is to install zinc metal strips near the ridge caps at the top of your roof. Zinc is a natural algae inhibitor, so any rainfall that hits the metal strip will “carry” the zinc down and over your shingles. 

Here’s a how to remove algae from your shingles: 

*Make sure to do your cleaning on a cool or overcast day with minimal wind, and wear protection (rubber gloves, long sleeves, overalls, goggles)

*Prevent damage from overspray by removing any lawn furniture, and cover landscaping and vegetation

*Use an appropriate cleaning solution or a homemade mix (1 gallon of bleach, 5 gallons of water, 1 cup of trisodium phosphate)

*Pour your cleaning chemical into a pump-type garden sprayer and thoroughly spray the roof

*Let the solution sit for 15-20 minutes, and then give the roof a good rinsing

*Use a garden hose to re-rinse the roof as many time as needed to remove any residue from the cleaning solution 

Where can I book the most reliable San Diego roof maintenance services?

What causes black streaks on roof shinglesHaving a clean and well-maintained roof provides you with two major advantages. First, it prevents rotting organic matter, mold, algae, and other debris from damaging your roof. Second, it increases the curb appeal of your property, which in turn boosts its real estate value.

As the top roofers in San Diego, 619 Roofing can supply you with the full range of roof cleaning, maintenance, installation, and repair services. Our 24/7 emergency technicians can quickly help you out regardless of whether you’re located in East Village or out in the suburbs. Get in touch with us today.