Roof Cleaning in Mendham, NJ
Low-pressure soft wash that lifts black streaks, moss & algae without touching your shingles.
Roof Cleaning in Mendham, NJ — Soft Wash That Kills the Black Streaks for Good
If you drive through the older streets off Hilltop Road or around the Borough near the historic district, you'll see it on half the roofs: dark vertical streaks running down the north- and shade-facing slopes. That's Gloeocapsa magma — a black algae that feeds on the limestone filler in asphalt shingles. It thrives here because Mendham sits under a heavy hardwood canopy, and North Jersey summers stay humid enough to keep those shaded roof planes damp for days at a time.
Out toward Brookside and the lower-lying lots along the brook, we see the worst of it. Big oaks and maples keep the sun off the roof, morning dew never fully burns off, and the shingles never get a chance to dry. That's a recipe for algae, and on cedar shake roofs — still common on some of the older colonials up here — it turns into green moss that holds moisture and shortens the life of the wood.
You can't pressure wash a roof. High pressure strips the granules off asphalt and splits cedar. We soft wash — low pressure and a cleaning solution that kills the organism at the root, so the streaks don't come right back next summer.
- Local crew that knows Mendham homes
- Soft-wash & low-pressure methods that protect your surfaces
- Licensed, insured & background-checked
- Upfront pricing — same-week scheduling
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What neighbors say
5.0 · 880+ Google reviews“Gallo Bros did an amazing job power-washing my home and roof. They assured me that if I had any concerns they would avail themselves to resolve them. After the cleaning a few leaves blocked the gutter after a heavy rain. They responded quickly and courteously, removing the blockage touched up ,y skylights as well. Before leaving they made sure I was satisfied. Oscar and his team came a few weeks later and sanded and sealed my paver walkway. They were polite and professional, explaining what they were doing, how long it would take, and instructions to ensure the best possible result. What I loved most was the professionalism in their communication. There were several days that we were rescheduled due to heavy rains and storms. The first thing they assured us of was their intent to make sure the job was done correctly. They would not come out to do the work, only to have it washed away. They stayed in contact every step of the way and I felt more than comfortable that the job would get completed the right way. If they couldn’t reach h me by phone they always left a voicemail or sent a text. I just happened to call them first in my search for roof cleaning, but I will never have to look further for these services again. I was really so impressed. Thank you Gallo Bros!”
Kim Wells
“I wanted power wash my backyard deck for a long time but they said it cannot be done due to the equipment was not accessible however Gallo Brothers had very long 400feet hose and did the power wash which was not done for many years. I am very happy they did a very good job specially Mark was very helpful to do front porch and walkway. It is speck clean this is exactly what I wanted to do. I do highly recommend Gallo Bothers meticulous job.”
Chong Cho
“Awesome experience. I called and left a message over a weekend, they called me back quickly and schedule appointment. Lucas showed up on time dress in press shirt and paints with a iPad taking notes and pictures. Provided a very reasonable quote and scheduled appointment. The truck 3 team showed up earlier than scheduled and could not have been any nicer. The had a small problem with gear and let me know. Ther office also called and apologized to inform me of the problem. Truck 3 team came back and finished the job. The job they did was excellent. You can see on before pictures I had staining around window where shutters were installed. The after picture you can hardly tell. Super professional, kind and fair price. Wish all vendors were as professional and trustworthy as worthy as Gallo Bros is.”
james Flatt
Roof Cleaning in Mendham — FAQ
Will roof cleaning damage my asphalt shingles?
Not the way we do it. Pressure washing absolutely will — it blasts the protective granules off and voids most shingle warranties. We soft wash at low pressure with a solution that kills the black algae without touching the granules. On the shaded, north-facing slopes common in Mendham where the streaking is worst, this is the only safe method.
I have a cedar shake roof — can that be cleaned too?
Yes, and it needs it more than asphalt. Cedar shakes on the older colonials around here hold moisture, and under the tree canopy they grow green moss that keeps the wood wet and rotting. We clean cedar with an even gentler low-pressure approach and the right solution so we lift the moss and algae without splitting or feathering the shakes.
How long before the black streaks come back?
Because we kill the algae at the root rather than just rinsing the surface, you typically get several years before it returns. How fast depends on your lot — a heavily shaded roof near Brookside with oaks hanging over it will regrow sooner than an open, sunny lot. We'll give you an honest read when we look at your roof.
How much does roof cleaning cost in NJ?
It ranges widely — from a few hundred dollars for a small ranch to several thousand for a large, steep or complex roof. Size, pitch, material, access and how much algae has built up all factor in. You get a firm price up front, free.
Will roof cleaning damage my shingles?
No. We soft wash with low pressure and a cleaning solution — the method asphalt-shingle makers recommend. High-pressure washing is what damages roofs; we never do that on a roof.
What are the black streaks on my roof?
That's a hardy algae called Gloeocapsa magma. It feeds on the limestone in your shingles and spreads in New Jersey's humidity. Soft washing kills it at the root, not just the surface.
How long does a roof cleaning last?
Usually 2–4 years. Because soft washing kills the algae instead of just rinsing it, the clean lasts far longer than a quick power-rinse.
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- A real person comes out and prices the work in front of you
- Exact price before anything starts, in writing
- Free, and there's no obligation to book the job
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(973) 500-8155info@gallobrospw.com