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 · 854+ Google reviews“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
“Holiday Outdoor Lighting Gallo Brothers Experience I always wanted outdoor lighting - but, never felt comfortable with other roof lighting companies - people, creativity/passion, equipment safety, timing - ability to handle challenging roof layout …. and concerns regarding ability to deliver The Gallo Brothers checked all of the boxes: Incredibly professional Went above and beyond - the roof was a challenge - other companies wanted to do lights along gutter line only because the roof had too many steep peaks and Gallo Brothers created a custom lighting solution across the entire roof. They had complete confidence that they could deliver and they killed it.. The Gallo Brothers are bright, young and hungry …. Experience for me was totally stress free The Gallo Brothers offered Creative design options/solutions They have the appropriate equipment to perform work in a safe efficient manner The Gallo Brothers Team was not only friendly and kind but, highly skilled. They were focused and enjoyed doing their job. They were very careful with equipment and determining safest way to get around complex roof and lawn and landscape Efficiency and punctuality are hallmarks of Gallo Brothers service I just chose the bulb color ... and had them walk me through all of the options. The pricing was fair and reasonable compared to their competitors. The other competitors were more expensive and offering was a lower level product (example - boring gutter line lights vs entire roof lighting experience) The Gallo Brothers were very transparent throughout entire process They over delivered from the picture that they designed and I approved in the beginning The work and lighting product experience speaks for itself - family, neighbors and friends love it I was blown away when the lights came on the night that I was home with family. It was such an incredible experience. I didn’t want to leave home for family event that night. It brightened up the entire block and created many smiles My kids asked me why I didn’t do the home lighting many years ago …. I would strongly recommend the Gallo Brothers to anyone who wants to light up their home and neighborhood and who want a hungry team of skilled professionals - who love what they do - and will design and deliver a bright experience with no stress. *I would also recommend locking them in soon before their capacity is dedicated to my neighbors and friends who were very impressed with them”
Anthony Martucci
“Absolutely outstanding job by the Galo Brothers today power washing our house! Honestly the best power washing job we have ever had done. The house looks brand new again, every detail was handled with care, and the difference is unbelievable. They were professional, thorough, hardworking, and took real pride in their work. It’s rare these days to find a company that exceeds expectations, but they absolutely did. Highly, highly recommend the Galo Brothers to anyone looking for top notch service and incredible results!”
Bruce Bosland
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.
North Jersey · 854+ five-star reviews
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Choose a slot that actually suits you and it's confirmed on the spot — no phone tag, no waiting on a callback.
- 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
Rather talk it through?
(973) 500-8155info@gallobrospw.com