By Brayden Rollins
If your roof has dark streaks running down it, you might assume it’s just aging or dirt. The truth is more concerning — and more fixable — than most Chapin homeowners realize.
Drive through just about any neighborhood in Chapin and you’ll spot them: dark black or greenish streaks running vertically down otherwise normal-looking roofs. They’re so common that most homeowners assume it’s just what happens to a roof over time. But those streaks aren’t dirt, and they’re not harmless.
“What you’re looking at is a type of bacteria called Gloeocapsa magma,” explains Brayden Rollins, owner of Monster Pro Wash, a locally owned exterior cleaning company. “It feeds on the limestone filler in asphalt shingles. So it’s not just sitting on your roof — it’s actually eating it.”
How It Damages Your Roof
The bacteria retains moisture against the shingle surface, which accelerates the loss of the protective granules that give asphalt shingles their durability and weather resistance. Over time, this means a shorter roof lifespan.
“We’re talking about a roof that should last 25 to 30 years potentially losing five to ten years because of something that’s completely removable,” Rollins says.
There’s also an energy cost. Dark, algae-covered roofs absorb significantly more heat than clean, reflective ones. In a South Carolina summer, that translates directly to higher cooling bills.
“Homeowners are paying more to cool their house because their roof is covered in dark bacteria,” he says. “Most people don’t connect those dots.”
Why You Should Never Pressure Wash a Roof
Some homeowners consider renting a pressure washer and handling it themselves. Rollins is emphatic that this is a mistake.
“Every major shingle manufacturer — GAF, CertainTeed, Owens Corning — explicitly says do not pressure wash your roof,” he explains. “It strips the granules right off the shingles and voids your warranty. We’ve seen roofs that were basically destroyed by someone trying to clean them with a pressure washer.”
The correct method is called soft washing, which uses extremely low pressure (about the same as a garden hose) combined with a specialized cleaning solution that kills the bacteria, algae, moss, and lichen without any mechanical force on the shingles. This is the method recommended by the Asphalt Roofing Manufacturers Association.
“The solution does all the work,” Rollins says. “The bacteria dies on contact, and over the next few days the roof returns to its original color. The results are dramatic — we’re talking about a roof that looks ten years younger.”
For a detailed breakdown of how the process works, Monster Pro Wash has published a complete roof cleaning guide on their website.
When to Get Your Roof Cleaned
Rollins says spring is an ideal time because the moderate temperatures allow the cleaning solution to work effectively, and homeowners can enjoy the results all summer long. Most roofs stay clean for three to five years after a professional soft wash.
“If you can see those black streaks from the street, it’s time,” he says. “And the sooner you address it, the more life you’re preserving on your roof.”
Monster Pro Wash provides professional roof cleaning in Chapin and the Lake Murray area using the manufacturer-recommended soft wash method. Free estimates are available at (803) 239-1473 or at monsterprowash.com.
Monster Pro Wash is locally owned and operated, fully insured, and rated 5 stars on Google. They serve homeowners throughout the SC Midlands.
