It happens to every Atlanta house, regardless of the neighborhood or property price, and it's embarrassing. Without roof cleaning, the black streaks slowly spread across the shingles like they're crawling down the roof. These streaks are cause by black mold, also known as roof algae.
Yes, the black algae looks terrible on your roof, but you may not think the black streaks pose any real threat. Unfortunately, the streaks can do more than make your home's roof look ugly, they can cost you money. These streaks can shorten the life of the roof, reducing energy costs and property value.
Roof algae causes small amounts of moisture to sit on your shingles. Over time, the water can leak into the shingles and damage them. To remove the streaks, you can hire a professional or do the work yourself.
Why do black steaks occur?
In the past, only Atlanta homes located in woody areas fell victim to roof algae. The blue-green algae called Gloeocapsa Magma, was already on the exposed rocks and trees around these homes. Wind and animals spread the algae spores to roofs. Eventually, the algae jumped from roof to roof, spreading the black streaks well beyond the wooded neighborhoods.
You'll notice the roof on the side of your house that is shaded collects the black mold first. Moisture that lingers on roofs in shaded areas helps algae to grow and spread. Shingles usually dry out when the sun hits them, so shingles on the sunnier side don't get black mold as quickly.
The material used to make shingles helps to spread the mold, too. Most companies that make asphalt roof shingles use crushed limestone during the manufacturing process. Unfortunately, once the spores are on your roof, the crushed limestone in the shingles helps the roof algae to grow and spread to different areas of the roof and gutters.
You have two ways to eliminate these unsightly streaks: you can do it yourself, or you can hire a professional.
Eliminate the black streaks yourself
You'll want to set aside a whole morning or afternoon to clean your roof shingles. Choose a day in Atlanta that isn't too cold. The temperature of your shingles must be above 35 degrees for at least four hours before using any cleaner.
You'll also want to shop around for the best cleaning solution to use. Ask a professional or sales rep at a home improvement store to offer suggestions.
Before you begin, make sure you have an adequate ladder and a pump sprayer to reach all parts of your roof. Most home improvement stores sell these sprayers, also called insecticide sprayers. Your roof's height will determine how much pressure you need in a pump sprayer. Ask your home improvement store representative to give you some advice when choosing a sprayer. Don't use a hose sprayer; it won't give you the correct ratio of water-to-cleaner in your solution.
Mix your cleaner with water per the directions and let it sit for about half an hour. To get the best results, stand extremely close to the roof stains. Start by spraying at the roof's peak and work your way down to the eaves. Spraying across or upward on your roof could loosen the shingles. Wear a mask, eyewear, and protective clothing while spraying the chemicals.
Instead of applying the cleaner to the entire roof, focus on one small section at a time. When you try to clean the entire roof all at once, you may miss some areas. Once you've finished spraying down the roof, rinse the cleaner from the shingles using water, or as directed by the manufacturer.
You may need to reapply the cleaner to areas that have a larger amount of mold. Make sure you rinse the second application off of your shingles, as well.
Hiring a roofing company
If you're uncomfortable or not sure about completing the entire roof cleaning process, it's best to choose a roofing professional. He or she can survey the amount of black streaks on the roofs and provide you with an estimate of the cost. Having your home's roof professionally cleaned can save you money, time and the cost of hiring a roofer later for more extensive repairs.
Many Atlanta roofing companies remove black mold from roofs. Unlike the majority of homeowners who try to do the work themselves, roofers have years of experience with black algae removal. They know which products to use and the right amount of pressure to apply to wash black streaks off the roof.