Roof Washing
Safe, low-pressure roof washing that kills black algae (Gloeocapsa magma) at the source and restores your shingles — without the high pressure that can damage them.
What Is Roof Washing?
Those ugly black streaks running down your roof aren't dirt — they're a type of blue-green algae called Gloeocapsa magma, and it's incredibly common across the Carolinas. It feeds on the limestone filler in modern asphalt shingles, thrives in our warm, humid climate, and spreads from roof to roof on wind and rain. Left untreated, it doesn't just make your home look old and neglected — it can actually shorten the life of your shingles by holding moisture against the surface and accelerating granule loss.
The mistake many homeowners and even some contractors make is reaching for high pressure to remove the streaks. That's the worst thing you can do to a roof. High pressure — even from a pressure washer dialed down — strips the protective granules off your shingles, forces water underneath them, and can void your manufacturer's warranty. Once those granules are gone, they don't come back, and your roof ages years in minutes.
The correct method is soft washing: a specialized, low-pressure application of an algaecide that kills the organism at the root, followed by a gentle rinse. No granules lost, no water forced under shingles, no warranty concerns. The results last 2–3 years because the algae is actually eliminated — not just blown off to regrow next season. For a fraction of what a premature roof replacement costs, a professional roof wash restores your home's curb appeal and protects one of your biggest investments.
Why It Matters
Removes Black Streaks
Eliminate the ugly black algae streaks that discolor roofs across the Carolinas and make homes look decades older than they are.
Protects Shingles
Soft wash — never high pressure — protects your shingle granules and preserves the manufacturer's warranty on your roof.
Extends Roof Life
Removing algae, moss, and lichen helps prevent premature shingle deterioration, moisture damage, and costly early replacement.
Improves Curb Appeal
A clean roof transforms the entire look of your home — often the single biggest visual improvement you can make for the price.
Kills at the Source
Our algaecide solution kills algae spores at the root, so the streaks stay gone for years — not just until the next humid season.
Safe for Landscaping
We protect, pre-treat, and rinse all plants and landscaping throughout the process to keep everything healthy and green.
How We Get It Done
A proven, step-by-step approach that protects your property and delivers spotless results — every time.
Roof Inspection
We inspect your roof from the eaves and ladder, identify the type and extent of algae, moss, or lichen growth, and check for any damaged or missing shingles we need to flag.
Protect Landscaping
We water and pre-treat all plants below the eaves, cover sensitive vegetation, and divert downspouts to protect your foundation plantings from any runoff.
Soft-Wash Application
We apply our algaecide solution at low pressure — never more than a garden hose — from the bottom up, letting it dwell and kill algae at the root.
Targeted Treatment
Stubborn moss or lichen gets a second application and extra dwell time. We never scrape or force growth off — we let the solution do the work.
Gentle Rinse
A light, low-pressure rinse washes away dead algae and residue, revealing clean, streak-free shingles without granule loss.
Final Inspection
We walk the perimeter, check the results, rinse any overspray off siding or glass, and make sure your property is left clean and tidy.
Surfaces We Clean Safely
We match the method and pressure to the surface — protecting your property while delivering a deep, lasting clean.
Safe For
- Asphalt shingles (architectural and 3-tab)
- Metal roofing (painted and unpainted)
- Clay and concrete tile roofing
- Slate roofing
- Membrane and flat roofing (TPO, modified bitumen)
- Roof flashing, vents, and boots
Clean With Care
- Aged or visibly damaged shingles — we flag them before cleaning and reduce dwell time
- Wood shake shingles — require a gentler solution mix and extra care
- Solar panels — we avoid direct application and work around them
- Roofs with heavy moss buildup — may need a second visit after the moss dies and releases
- Skylights with aging seals — we avoid direct spray on the seals
Time to Call Gates?
If you've noticed any of these around your property, it's probably time to schedule a cleaning.
Black or dark brown streaks running down your roof from the eaves
A roof that looks dirty or stained even on a clear, sunny day
Green moss growing in patches, especially in shaded valleys
White or grey lichen spots scattered across the shingles
Granules collecting in your gutters or at the base of downspouts
Your roof looks visibly different from neighbors with newer or cleaner roofs
You're selling your home and the roof is drawing negative attention in photos
It's been 3+ years since your roof was last cleaned — or it never has been
How Often Should You Schedule This?
A professionally soft-washed roof typically stays clean for 2–3 years in the Carolinas because we kill the algae at the root. Heavily shaded roofs or properties surrounded by mature trees may need cleaning every 2 years. Full-sun roofs with good airflow can often go 3 years between cleanings. We recommend scheduling a roof inspection annually so we can spot regrowth early — it's far easier and less expensive to maintain a roof than to replace one.
Roof Washing FAQ
Roof Washing Across the Carolinas
Book roof washing in your area — we serve all of North Carolina and parts of South Carolina.
Ready for a Spotless Property?
Join hundreds of NC & SC homeowners and businesses who trust Gates for spotless, guaranteed results. Get your free quote today.