Here is a really good roof cleaning article that was partially written by our good friend Marcus Raif of Katy Memorial Roof Cleaning in Texas. Marcus is a fellow member of the Roof Cleaning Institute Of America, and is also an RCIA Certified Roof Cleaner.
The Pittsburgh resident’s roof was covered with moss and black streaks.
“It looked terrible,” Hollingshead said. “It looked like it was in poor condition. We had a roofer look at it but got an astronomical estimate. It was tens of thousands of dollars for a new roof.”
The roofing company told Hollingshead that they’d be happy to replace her roof, but that she really didn’t need it. What she needed was for it to be cleaned.
Over the past two decades, more homeowners across the U.S. have experienced the very same issues with their roofs as Hollingshead. Gloeocapsa magma, a type of bacteria that presents as the black streaks, is the culprit.
“About 15 years ago, in the manufacturing process, (fiberglass) roof manufacturers added limestone in the asphalt shingle mix,” explained Brad Iannacchione of Soapy Roof in New Kensington, Pa. “That’s what (the bacteria) enjoys eating.”
Though there’s no demonstrated proof that the bacterium is harmful to roofs, industry experts say it can lead to premature rotting of the shingles if left untreated. Plus, the appearance of those streaks can lower a home’s value if you’re trying to sell it. In an effort to curtail unnecessary roof replacement, some insurance companies are even making it a requirement homeowners have their roofs cleaned, or risk losing their policy. A professional roof cleaning will usually rid those black streaks for five years or longer.
“The biggest reason is aesthetics, as far as making sure your house looks nice again and clean,” Raif said. “(Plus), the black on the roof raises the attic temperatures within the house. It can reduce your electric bills by reducing the heating of your attic by getting rid of the black streaks.”
Both Iannacchione and Marcus Raif of Katy Memorial Services in Katy, Texas, recommend a non-pressurized cleaning as the most effective method for removing the black streaks.
“You’ll blow the granules off an asphalt roof” with pressure washing, Raif said.
“The Asphalt Roofing Manufacturers Association recommends you don’t use any pressure whatsoever on the roof.”
The “soft-wash” method using a chlorine-based chemical wash is the best way homeowners should go for a roof cleaning, both experts say.
“We don’t use any more pressure than a garden hose to spray our cleaning solution” on the roof, Iannacchione said. “By the time we leave, the roof is 99 percent clean. The other 1 percent will be gone after the first rain. A lot of times, homeowners themselves will get up there with the pressure washer, and frankly, it works. It will take care of those black streaks. Unfortunately, those folks just ruined their roofs, in my opinion, because there are a lot of different granules and little stones on the shingles. I’ve talked to a lot of different roofing manufacturers, and it will actually void the warranty that homeowner has for the roof.”
Before hiring a company to clean, ask about the method the technicians will use. Raif said he’s certified by the Roof Cleaning Institute of America. Check that the company carries liability and workers’ compensation insurance, so you’re protected in the event they cause unforeseen damage or someone gets injured on the job. A roof cleaning for homes can range in price from about $250 to $1,000 or more, depending on the size of the home, pitch of the roof and how dirty it is.
If you do decide to have your roof cleaned, be sure the company protects grass, shrubs and flowers from runoff. Both Raif and Iannacchione said their companies always send two technicians to the job; one who applies the cleaner and one who stands on the ground, constantly saturating the grass and plants with water from a hose.
Hollingshead said she noticed an immediate difference after having her roof cleaned and is glad she didn’t pay to replace it.
“They did an absolutely excellent job,” Hollingshead said. “He came out and did the roof in about five hours. It’s absolutely immaculate. It looks like a new roof. The roof was in good condition, but it didn’t show it. But now that it’s cleaned, it really looks like a brand new roof. It saved us tens of thousands of dollars.”