If you live in Trolley Square, the Highlands, or Westover Hills and you have noticed dark gray or black streaks spreading across your roof shingles, you are not looking at dirt or age. You are looking at Gloeocapsa magma, a cyanobacteria that thrives in the humid Mid-Atlantic summers we get here in Wilmington every single year. Left alone, it feeds on the limestone filler in asphalt shingles, shortening roof life and making an otherwise well-kept home look neglected from the street.
True Blue Pro Wash handles roof soft washing throughout Wilmington and the surrounding New Castle County zip codes — 19801, 19805, 19806, and 19807 among them. We use a low-pressure, high-dwell soft washing process approved by shingle manufacturers like GAF and CertainTeed. That means biodegradable cleaning agents do the work, not water pressure that could lift or crack tabs and void your warranty.
Why Wilmington Roofs Get So Much Algae Growth
Wilmington sits in a humidity corridor that runs right up the Delaware River valley. Summers are hot and sticky, winters bring freeze-thaw cycles that open up micro-cracks in shingles, and spring pollen coats every surface with organic material that feeds algae and lichen. North-facing and shaded roof planes in neighborhoods like Greenville and Brandywine Hundred are especially prone to heavy algae coverage because they stay damp longer after rain. If your neighbor already has the streaks, spores are likely already on your roof too — they just need moisture and time.
Our Roof Soft Washing Process
We do not get up on your roof with a pressure washer and blast water under your shingles. That approach causes granule loss, can force water into your attic, and will void most manufacturer warranties. Our process works like this:
- Pre-rinse and protect: We wet down your landscaping, downspouts, and any adjacent surfaces before we start.
- Low-pressure application: We apply a professional-grade sodium hypochlorite solution mixed with surfactants at low pressure — well under 100 PSI at the nozzle.
- Dwell time: The solution sits and breaks down the algae, mold, and lichen at the root. No scrubbing needed.
- Rinse: A gentle rinse clears the dead organic material and leaves your shingles clean and intact.
- Post-treatment: We neutralize runoff and do a final check of gutters and downspouts to make sure nothing is clogged.
How Long Does Roof Soft Washing Last in Delaware?
In the Mid-Atlantic climate, most homeowners in Wilmington see results that last three to five years on a treated roof. Homes with heavy tree canopy or north-facing slopes may need attention on the shorter end of that range. Adding a zinc or copper strip at the ridge can slow algae regrowth between cleanings — we are happy to talk through that option when we quote your job.
Signs Your Wilmington Roof Is Ready for Soft Washing
- Dark gray or black streaks running down shingle courses
- Green or yellow-green algae patches on north-facing slopes
- White or gray lichen colonies that feel crusty to the touch
- Roof that looks significantly darker than it did five years ago
- Streaks visible from the street that make the house look older than it is
- HOA notice in neighborhoods like Westover Hills or the Highlands flagging your roof appearance
Roof Soft Washing vs. Pressure Washing: What Wilmington Homeowners Need to Know
A lot of guys in this area will put a pressure washer on a roof because it is fast and looks dramatic in photos. The problem is that asphalt shingles are made of compressed fiberglass or organic mat with a layer of mineral granules on top. Those granules protect the mat from UV. High-pressure water strips granules, accelerates aging, and sends them straight into your gutters. Soft washing uses chemistry instead of pressure. The cleaning agents penetrate the algae's cell walls and kill it at the root. Rinsing at low pressure clears the residue. Your shingles keep their granules, your warranty stays intact, and the results last longer because you killed the organism rather than just blasting the surface layer off.
Areas We Serve in and Around Wilmington
- Trolley Square (19806) and the Highlands (19806)
- Westover Hills (19807) and Greenville (19807)
- Brandywine Hundred (19810)
- Downtown Wilmington and Riverside (19801, 19802)
- Elsmere and Edgemoor (19805)
- New Castle (19720) and surrounding New Castle County communities
Bundle and Save: Roof Soft Washing Plus House Washing
When we are already set up at your property for a roof cleaning, adding a full exterior house wash makes a lot of sense. The same algae and mold spores that streak your roof are working on your siding, window frames, and foundation walls too. Wilmington homes in the 19806 and 19807 zip codes often have older brick or stucco exteriors that collect green and black biological growth along the waterlines and on the north-facing walls. Bundling roof and house soft washing in a single visit saves you a service call charge and gets your whole property looking sharp in one morning's work.
True Blue Pro Wash is a local company, not a franchise. When you call (302) 757-9755, you are talking to someone who works in Wilmington and knows why the north side of a house on a tree-lined street in the Highlands is going to look different from a south-facing ranch in Westover Hills. We price honestly, show up on time, and stand behind our work. That is the whole pitch.
Frequently Asked Questions
Is roof soft washing safe for asphalt shingles on older Wilmington homes?
Yes. Soft washing uses water pressure well below 100 PSI at the nozzle, which is far lower than rain hitting your roof during a storm. The cleaning solution does the work, not pressure. This method is specifically recommended by shingle manufacturers and will not damage granules or lift shingle tabs on properly installed roofs, including the older architectural shingles common in Wilmington's Highlands and Westover Hills neighborhoods.
How long does roof soft washing take on a typical Wilmington house?
Most single-family homes in Wilmington zip codes like 19806 and 19807 take two to four hours from setup to cleanup. Larger roofs, steep pitches, or roofs with heavy lichen buildup that needs additional dwell time may run a bit longer. We will give you a time estimate when we quote the job.
Will the cleaning chemicals harm my landscaping or lawn?
We take precautions on every job. Before applying any solution we wet down all surrounding plantings, shrubs, and grass. Our rinse process also neutralizes runoff. Most established landscaping handles our process without issue. If you have particularly sensitive plantings near your foundation or downspouts, let us know when you book and we will plan accordingly.
How long will it be before the black streaks come back after soft washing?
In the Delaware and New Castle County climate, most treated roofs stay clean for three to five years. Homes with heavy tree canopy, persistent shade, or north-facing slopes may see new growth return sooner. An optional zinc or copper ridge strip can slow algae regrowth between cleanings. We are happy to discuss that option during your estimate.
Do I need to be home when you clean my roof?
Not necessarily. We do need access to an outdoor water spigot and need to be able to get around the perimeter of the house. Many Wilmington homeowners leave us a note with water access instructions and return to a clean roof. We will walk through the access requirements with you when you schedule.
Does True Blue Pro Wash serve areas outside Wilmington city limits?
Absolutely. We cover all of New Castle County, including Trolley Square, Brandywine Hundred, Greenville, Hockessin, Newark, Bear, and Middletown. We also serve Southeast Pennsylvania communities like Chadds Ford and West Chester, plus Southwest New Jersey including Pennsville and Salem. Call (302) 757-9755 to confirm your address is in our service area.