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Exterior Cleaning

Professional Roof Cleaning & Soft Wash — Safe for Every Shingle, Tile & Metal Roof

Black streaks, algae, moss, and lichen are slowly destroying your roof. NorTech’s professional roof cleaning and soft wash service eliminates biological growth at the root — without a drop of damaging pressure — protecting your roof, your shingles, and your warranty.

ARMA-Compliant Soft Wash Method
Warranty-Safe Cleaning
Biodegradable Solutions
Nationwide Service
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First-Time Customer Offer

New to NorTech? Save 15% off your first roof cleaning or soft wash service — any roof type, any size.

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Critical Warning

Why Pressure Washing a Roof Is a Costly Mistake — and What to Use Instead

This is the most important thing to understand about roof cleaning. The method matters more than anything else. Using the wrong one doesn’t just do a bad job — it actively damages your roof and can void your warranty.

Pressure Washing a Roof Voids Most Shingle Manufacturer Warranties

The Asphalt Roofing Manufacturers Association (ARMA) explicitly states that pressure washing is not an approved cleaning method for asphalt shingles. High-pressure water blasts away the protective granule layer, shortens roof lifespan, and gives warranty companies grounds to deny future claims. If a contractor recommends pressure washing your shingle roof — walk away.

Pressure Washing a Roof

  • Strips protective granules from asphalt shingles
  • Voids most shingle manufacturer warranties
  • Forces water under shingles and into the decking
  • Spreads algae spores across the roof surface
  • Only removes surface growth — organisms regrow fast
  • Can crack or lift tiles on clay and concrete roofs

Roof Soft Washing (NorTech’s Method)

  • ARMA-recommended low-pressure application
  • Complies with shingle manufacturer warranty requirements
  • Kills algae, moss, and lichen at the biological root
  • Results last 1–3 years vs. months with pressure washing
  • Safe for asphalt, tile, metal, and flat roofing systems
  • Biodegradable solutions safe for landscaping below
Roof Types We Clean

Roof Cleaning Services for Every Roofing Material

Every roof type has specific cleaning requirements. NorTech technicians are trained on the correct solution concentration and application method for each material.

Asphalt Shingle Roofs

The most common residential roof type and the most vulnerable to Gloeocapsa magma algae. Soft washing removes black streaks and kills the organism without touching the granule layer.

Clay & Concrete Tile Roofs

Tile roofs crack under high pressure. Soft washing safely removes algae, moss, and lichen from porous tile surfaces without risking structural damage to the tiles or mortar.

Metal Roofing Systems

Metal roofs develop algae streaking and surface oxidation. Low-pressure soft washing restores the appearance without scratching coatings or voiding metal roofing warranties.

Flat & Low-Slope Roofs

Flat roofs accumulate standing organic debris, algae, and mold more than pitched roofs. Soft washing clears biological growth from membrane and built-up roofing systems.

Cedar Shake & Wood Roofs

Wood shakes require the gentlest approach — low-pressure application with a precisely diluted solution that kills moss and mildew without drying out or splitting the wood fibers.

Slate Roofs

Slate is extremely durable but brittle under mechanical stress. Soft washing is the only appropriate cleaning method — it cleans without any risk of cracking or dislodging slates.

What’s Actually Growing Up There

The Organisms Behind Roof Staining & Damage — and Why They Require Professional Roof Cleaning

Those stains aren’t just cosmetic. Each organism that grows on a roof causes a different type of damage and requires a specific cleaning approach to fully eliminate.

Gloeocapsa Magma (Roof Algae)

Responsible for the black streaks seen on most residential roofs. This cyanobacteria feeds on the limestone filler in asphalt shingles, spreads via wind and rain, and retains moisture in the shingle surface — accelerating granule loss and UV damage over time.

Moss

Moss holds moisture against the roof surface 24/7, causing shingles to lift, curl, and deteriorate at a dramatically accelerated rate. It typically grows on north-facing and shaded slopes where moisture lingers longest. Left untreated, moss roots penetrate shingle layers and reach the decking below.

Lichen

The most destructive roof organism. Lichen is a symbiotic combination of algae and fungi that anchors itself directly into the shingle surface with root-like structures called rhizines. It cannot simply be washed off — it must be killed with soft wash solution and allowed to release naturally over several weeks.

Mold & Mildew

Common on flat, low-slope, and shaded roofs. Mold and mildew don’t damage shingles the same way algae and lichen do, but they indicate chronic moisture issues and create the conditions that allow more destructive organisms to take hold.

Pricing Transparency

Roof Cleaning & Soft Wash Cost Factors

Roof cleaning costs vary based on the size and pitch of the roof, the type of roofing material, and the extent of biological growth. Click any factor to learn more.

Larger roof area requires more solution and more labor time — this is the primary cost driver for most roof cleaning jobs.
Steeper roofs require additional safety equipment, slower movement, and more careful application — all adding to labor time and cost.
Cedar, slate, and tile require specialized solution concentrations and more careful application than standard asphalt shingles.
Heavy black streak coverage requires stronger solution and longer dwell time to fully eliminate the Gloeocapsa magma organism.
Dense moss and lichen infestations require pre-treatment and may need a follow-up rinse visit after the organism has died and dried.
Complex roofs with many angles, valleys, and planes take longer to fully treat than simple gable designs.
Preventive cleaning every 1–3 years is significantly less costly than treating a heavily infested roof.

Every roof cleaning job is quoted to your specific property. Request a free quote — no obligation. Request a free quote — no obligation.

Certified & Insured Every technician, every job
The NorTech Promise Our service guarantee
ARMA-Compliant Method Warranty-safe soft washing only
4.8-Star Rated 1,000+ verified reviews
Customer Reviews

What Customers Say About Our Roof Cleaning & Soft Wash Service

4.8

Based on 1000+ ratings

“My roof had black streaks running down both sides for at least four years. I kept putting it off thinking it would cost a fortune. The soft wash took two hours and the streaks are completely gone. Wish I’d done it sooner.”

— Raymond B.

“Our HOA sent us a letter about the moss on the north slope. NorTech came out within the week, treated the whole roof, and we passed inspection with no issues. Worth every penny to avoid the HOA fine.”

— Janet & Tom F.

“Results on the algae were excellent — streaks gone, roof looks clean. My only complaint is the lichen on the east side didn’t fall off right away. Technician explained it takes a few weeks to shed after treatment. Would’ve been helpful to know that before the appointment, not after.”

— Carol M.

“I specifically asked if they used soft wash and not pressure washing because I’d heard pressure washing voids warranties. They confirmed soft wash only and even explained why. That level of knowledge sold me immediately.”

— David L.

“Really happy with the result. Had a small area near the chimney that was still slightly dark after the first pass — they came back and retreated it at no charge. Good follow-through on their guarantee.”

— Brenda K.

“Three quotes from three companies. The other two wanted to pressure wash. NorTech was the only one that recommended soft wash and explained the ARMA standard. Instantly knew they were the right call.”

— Patrick O.
Got Questions?

Roof Cleaning & Soft Wash — Frequently Asked Questions

No. Pressure washing asphalt shingle roofs is not recommended and can void your roofing warranty. High-pressure water blasts away the granule coating on shingles, accelerating wear and reducing the roof’s lifespan. NorTech uses soft washing — a low-pressure, chemical-based method — which is the only approach recommended by the Asphalt Roofing Manufacturers Association (ARMA) for cleaning shingle roofs.
Black streaks on roofs are caused by Gloeocapsa magma, a cyanobacteria that feeds on the limestone filler in asphalt shingles. It spreads from the ridge downward via wind and water runoff, creating dark vertical streaking. Without treatment it continues to spread, traps moisture in shingles, and accelerates deterioration.
A professional roof soft wash typically prevents algae, moss, and lichen from returning for one to three years depending on local climate, tree coverage, and roof shading. Homes in humid or heavily wooded areas may see regrowth sooner. Most homeowners schedule a preventive wash every two years.
Soft washing does not damage shingles. The low-pressure application is gentle enough to avoid dislodging granules or cracking shingles. The biodegradable cleaning solution breaks down biological growth chemically — not mechanically. This is why soft washing is endorsed by ARMA as the correct method for asphalt shingle roof cleaning.
Roof cleaning costs vary based on roof size, pitch, material type, and the extent of algae, moss, or lichen growth. Steeper roofs and heavily covered surfaces require more time and solution. Contact NorTech for a free, no-obligation quote specific to your roof.
Most residential roof soft wash jobs take two to four hours. Larger roofs, complex multi-plane designs, or roofs with heavy moss or lichen coverage may take longer. The soft wash solution also requires dwell time to fully break down biological growth before rinsing.
Yes. Soft wash solution kills moss and lichen at the root. Heavy growth may not fall off immediately — it typically dries up and sheds over several weeks after treatment as rain and wind carry it off the surface. For heavy infestations, a follow-up rinse visit may be recommended.
Pressure washing can void many shingle manufacturer warranties. Soft washing does not. In fact, most roofing manufacturers specifically recommend low-pressure soft washing as the only acceptable cleaning method. NorTech’s roof cleaning process is designed to comply with standard roofing warranty requirements.
Service Coverage

Roof Cleaning & Soft Wash Services Near You

NorTech provides professional roof cleaning and soft wash services across the United States. We serve hundreds of cities including:

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Stop Letting Algae and Moss Shorten the Life of Your Roof

Get a free, no-obligation quote for professional roof cleaning and soft wash. NorTech’s certified technicians use only warranty-safe, ARMA-compliant methods — no pressure washing, no shortcuts.

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