How We Removed 5 Years of Algae from a Home in The Bluffs on the Cape Fear
- Nick Corbelli
- Aug 29
- 6 min read
Five years of green algae and black streaking came off a two story home in The Bluffs on the Cape Fear in a single day, using a low pressure soft wash instead of a pressure washer. The siding was stained, not damaged, so nothing needed replacing.
Nick and Chris Corbelli have been cleaning homes across the Cape Fear region for years, and this is one of the most common questions they hear.
A homeowner on Red Raspberry Road NE called us in early August with the question we get more than any other: is it too late? She had watched the shaded side of her house go from faintly green to solid green over about five summers. By the time she picked up the phone, she had already started collecting quotes to replace the siding.
She did not need new siding. She needed the growth killed and rinsed off.
What Does Five Years of Algae Actually Look Like on Siding?
Green algae is a living organism, not a layer of dirt. It anchors into the texture of the siding and spreads outward from the shaded, slow drying parts of the wall, which is why it almost always shows up first on the north side and under deep overhangs.
On this home in The Bluffs on the Cape Fear, the growth had settled into four separate places. The north wall was solid green from the foundation up to the second floor windows. The lap seams, meaning the horizontal grooves where each panel overlaps the one below it, held a darker band because water sits in them the longest. Under the gutter line there were vertical black streaks running down the fascia. The soffits and the porch ceiling had gone a flat gray that the homeowner had stopped noticing because it happened so slowly.
That slow part is what fools people. Nobody wakes up to a green house. It gains a little ground each humid summer until a visitor mentions it or an HOA letter shows up in the mailbox.
House Washing in Wilmington, NC
If your first warning came from your neighborhood association rather than your own eyes, you are in good company. We wrote about why an HOA violation for dirty siding is usually algae and what to do about it on a deadline.
Why Did the Algae Get That Bad in The Bluffs on the Cape Fear?
The Bluffs on the Cape Fear sits along the river north of Leland, surrounded by tidal marsh and mature hardwoods. That combination holds moisture against a house longer than an open inland lot does, and organic growth only needs moisture, shade, and something to cling to.
Mildew is a surface fungus that shows up as small black or gray speckling, and it usually travels with algae rather than instead of it. Homes in Leland NC often carry both at once, which is why a wall can look green from a distance and speckled black up close.
Three things made this particular house worse than its neighbors. The lot backs up to woods, so the rear wall never gets direct sun. The irrigation heads on that side were throwing water onto the lower panels every other morning. And the last cleaning had been a rented pressure washer five summers earlier, which knocked the surface stain off without ever killing what was growing underneath.
We see the same pattern in Waterford of the Carolinas and Magnolia Greens. Two houses built the same year, on the same street, can be five years apart in how they look, and the difference is almost always shade, sprinkler spray, and how long it has been since anyone treated the walls.
How Do You Remove Years of Algae Without Damaging the Siding?
Soft washing is a low pressure cleaning method that uses a cleaning solution to kill organic growth at the root, then rinses it away at about the pressure of a garden hose. The chemistry does the work instead of the force, which is what makes soft washing the right tool for siding that is stained rather than structurally dirty.
On the Red Raspberry Road job, the order went like this. We soaked the flower beds and the foundation plantings first, then moved the potted plants off the porch. We pre rinsed the walls, applied the solution from the bottom up so nothing ran dry and streaked, and let it sit while the green faded on its own. Then we rinsed from the top down, brushed the lap seams and the porch ceiling by hand where the film was holding on, and finished the gutter faces last. Total time on site was a little under six hours.
Nothing was scrubbed with a wand. Nothing was hit at pressure.
What Matters | Soft Washing | Pressure Washing |
Pressure at the wall | About the same as a garden hose | Roughly 1,500 to 3,000 PSI |
What removes the algae | A solution that kills the growth | Force that strips the surface stain |
Risk at lap seams and windows | Low, water is not driven behind panels | Water can be forced behind the siding |
How long results hold in Leland NC | Usually 12 to 18 months | Often about 6 months, roots stay behind |
Effect on older oxidized siding | Rinses evenly | Can strip in streaks and leave a patchy wall |
Siding manufacturers say the same thing in their own care guides. CertainTeed's instructions for cleaning vinyl siding call for a soft cloth or soft bristle brush and a bottom to top application, not a high pressure wand. If you are weighing whether to handle it yourself, we broke down soft washing versus DIY house washing in detail.
House Washing in Wrightsville Beach, NC
Was the Siding Damaged, or Just Dirty?
Mostly just dirty. Once the walls were rinsed, about 95 percent of the house came back to its original color, including the north wall the homeowner had written off.
Oxidation is the chalky, faded film that forms on vinyl and aluminum when years of sun exposure break down the surface. Two shutters on the south elevation had oxidized enough that they read slightly lighter than the rest after cleaning. That is age, not algae, and no wash brings it back. Everything else matched.
The one spot that needed a second pass was under a downspout where runoff had been feeding the same six inches of siding for years. That area took a second application and a hand brush. Left another two or three seasons, that band would have been the kind of staining that sets permanently, which is the real cost of putting this off.
We walked through a full year of neglect in a post on what happens when you skip exterior cleaning, and the roof usually goes the same direction as the walls, which is why we also cover protecting a roof from black algae in Brunswick County.
The homeowner canceled the siding quotes. A full house wash cost her a small fraction of a replacement, and the house looked the way it did when she moved in.
Frequently Asked Questions About Algae Removal and House Washing in Leland NC
Will removing algae damage my vinyl or Hardie board siding?
Not when it is done with a low pressure soft wash, because the water never hits the wall hard enough to lift panels or push moisture behind seams. Damage comes from high pressure wands, not from the cleaning solution. Window Cleaning Wizards soft washes every home in Leland NC and Wilmington NC for exactly that reason.
How long does a house wash last before the algae comes back?
In Leland NC, most homes stay clean for 12 to 18 months after a soft wash. Houses with heavy tree cover, a shaded north wall, or sprinklers hitting the siding tend to land at the shorter end of that range. Once a year is the schedule that keeps most homes here from ever getting bad again.
Do I need to be home while the house is being washed?
No. We need access to an outdoor spigot and to the gates around the property, and everything else happens outside. Most homeowners leave for the afternoon and come back to a finished job, and we walk the house with anyone who wants to see the results in person.
Will the cleaning solution kill my flower beds?
It will not, as long as the plants are protected properly before the work starts. We soak every bed with clean water first, move potted plants away from the walls, and rinse the landscaping again when the wash is finished. Plant protection is part of the job, not an add on.
By Nick Corbelli, Owner of Window Cleaning Wizards
Nick and his brother Chris have been cleaning homes across Wilmington, Leland, and surrounding communities for years. With a long track record of five-star Google reviews, they bring real hands-on experience to every job.
If the shaded side of your house has been getting greener every summer, it is almost never too late to bring it back. Call Nick and Chris at 910-727-4336 for a free estimate, or send a couple of photos to info@WindowCleaningWizards.com and we will tell you honestly what we think it needs.
This article was written with AI assistance and reviewed by Nick Corbelli, owner of Window Cleaning Wizards.
Comments