If you live in Westover Hills or Greenville, Delaware, zip code 19807, and you have been staring at those dark, spreading stains on your roof for a season or two, you already know something is off. Those streaks are not leftover grime from last winter. They are a living organism called Gloeocapsa magma, a cyanobacterial algae that feeds on the limestone filler in asphalt shingles. Left alone, it shortens shingle life, holds moisture against your roof deck, and can invite moss and lichen to follow. Around here, north-facing roof slopes are almost always the first to show it because they stay damp longer after rain.
True Blue Pro Wash has been cleaning roofs across New Castle County for years, and the Greenville and Westover Hills area is one we know well. The mature tree canopy on Kennett Pike and throughout the neighborhoods off Kirk Road creates heavy shade that keeps roofs wet. Combined with Delaware's humid summers and our classic stretch of freeze-thaw cycles from November through March, conditions here are nearly perfect for algae and moss growth. We get calls every spring from homeowners on streets like Greenville Road, Montchanin Road, and along the Westover Hills neighborhood boundaries who notice the streaks darkened again over the winter.
Why Soft Washing Is the Right Call for Asphalt Shingles
The Asphalt Roofing Manufacturers Association is clear on this: high-pressure washing voids most shingle warranties and blasts away the granules that protect the fiberglass mat underneath. Soft washing uses low pressure, typically under 100 PSI at the surface, combined with a professional-grade sodium hypochlorite solution and surfactants. The chemistry does the work, not the force. Gloeocapsa magma, moss spores, and lichen are killed at the root level, not just scrubbed off the surface. Rinsing comes last, gently, so granules stay exactly where they belong.
What the Soft Wash Process Looks Like at Your Home
Before we ever put a ladder against the fascia, we walk the property. We check gutters for blockages, look at the pitch and orientation of each roof plane, and note any dormers, skylights, or roof penetrations that need extra care during the rinse. We protect your landscaping, shrubs, beds, grass, by pre-wetting everything at ground level and by neutralizing the rinse water as it runs off. Greenville properties often have mature foundation plantings that we treat as carefully as we treat the roof itself.
- Pre-wet all landscaping and hardscaping below the drip line
- Apply biodegradable surfactant-enhanced soft wash solution to the full roof surface
- Dwell time allows the chemistry to kill algae, moss, and lichen colonies fully
- Low-pressure rinse from the ridge down, never against the shingle overlap
- Post-rinse neutralization of runoff to protect plants and lawn
- Final inspection of gutters and downspouts to confirm flow is clear
How Bad Can It Get? The Real Cost of Waiting
We hear a version of the same story regularly. A homeowner in Westover Hills notices light streaking in the spring. By fall it has spread across two or three roof planes. By the following spring, moss has taken hold along the eaves and in the valleys where debris collects. Moss is particularly damaging because it holds moisture like a sponge directly against the shingles and flashing. In a Delaware winter, that moisture freezes, expands, and works its way under shingle edges. What started as a cosmetic problem becomes a leak risk. Catching algae early, before moss establishes, means one soft wash treatment rather than a multi-stage remediation job.
Homes in the 19807 zip code also tend to carry significant curb appeal value. Whether you are on one of the historic streets in Westover Hills or on a larger lot near the Greenville Country Club corridor, visible black streaking is one of the first things a buyer's agent will flag. Realtors in this market have told us more than once that a clean roof photographs better, appraises better, and raises fewer questions during inspection. A roof soft wash from True Blue Pro Wash typically costs a fraction of what a shingle replacement would run, and it gets results within 24 to 48 hours of treatment.
Roof Soft Washing Paired with Gutter Service
While we are on the roof, many Westover Hills and Greenville homeowners ask us to combine the soft wash with a gutter cleaning and brightening service. It makes sense. Algae and debris from the roof flush into the gutters during every rain event, and if those gutters are already backed up with leaves and seed pods from the surrounding tree canopy, you can develop fascia rot and soffit damage faster than you might expect. We flush the gutters, clear the downspouts, and optionally brighten the exterior gutter faces to remove the dark oxidation tiger-striping that shows up on white and cream aluminum gutters. It is one visit, two problems solved.
Signs It Is Time to Schedule a Roof Soft Wash
- Dark gray or black streaks running vertically down the shingle surface
- Green or brownish-green discoloration along the north or shaded roof slopes
- Visible moss patches, especially near valleys, dormers, or the eave line
- Gutters overflowing despite being cleaned, algae mat buildup slowing drainage
- A neighbor's roof was recently cleaned and yours now looks noticeably darker by comparison
- You are planning to list the home and want it looking its best before listing photos
Serving Westover Hills, Greenville, and the Broader 19807 Area
True Blue Pro Wash runs routes through New Castle County regularly, and Greenville and Westover Hills are stops we make often. We work throughout the 19807 zip code as well as neighboring 19806 (the Highlands and Trolley Square area) and 19810 (Brandywine Hundred). If you are further out toward Hockessin, Pike Creek, or Newark, we cover those communities too. Give us a call at (302) 757-9755 to discuss your roof, get a straight answer about what we see and what it will cost, and schedule at a time that works for you. No pressure, no runaround, just clean roofs done right.
Frequently Asked Questions
Will soft washing damage my shingles or void my roof warranty?
No. Soft washing uses low pressure, well under 100 PSI at the surface, combined with a diluted cleaning solution. The Asphalt Roofing Manufacturers Association actually recommends low-pressure chemical cleaning as the correct method. High-pressure washing is what voids warranties and blasts off granules. Our approach is safe for virtually all asphalt shingle roofs including architectural and dimensional styles common in Westover Hills and Greenville.
How long does it take for the black streaks to disappear after treatment?
Most roofs look noticeably cleaner immediately after the rinse. Over the following 24 to 48 hours, any remaining discoloration continues to fade as the treatment finishes working. Full results are typically visible within a week, especially after the first rain rinses residual debris off the shingle surface.
How often does a roof in the Greenville or Westover Hills area need to be soft washed?
It depends on the tree cover, roof pitch, and orientation of your specific home. North-facing slopes with heavy shade in zip code 19807 can show algae regrowth in as few as two to three years. South-facing slopes with good sun exposure may go four to six years between treatments. We can give you an honest assessment when we quote the job.
Is the cleaning solution safe for my landscaping and my pets?
We pre-wet all planting beds, shrubs, and lawn areas before applying the soft wash solution, and we neutralize runoff during the rinse. We ask that pets stay indoors or away from the work area during the job and for about an hour afterward while surfaces dry. Once dry, the treated surfaces are safe.
Can you clean a steeply pitched or multi-story roof in Westover Hills?
Yes. We use extension wands and dedicated low-pressure roof-cleaning equipment that allows us to apply solution and rinse from ladder positions or from the ground on many pitches. We assess access, slope, and height before every job and bring the right setup for the specific roof. Safety is not something we compromise on.
Do you offer any kind of maintenance plan so I don't have to remember to call every few years?
We do offer ongoing maintenance agreements for homeowners in New Castle County who want to stay ahead of algae and gutter buildup. Call us at (302) 757-9755 to talk through what a plan would look like for your home in Greenville, Westover Hills, or anywhere else in the 19807 area.