Best Roof Cleaning Products for Moss, Algae & Stains

Jul 15, 2025

Roof cleaning products can help homeowners maintain a cleaner, longer-lasting roof by eliminating moss, algae, and stains that build up over time. A clean roof not only enhances your home’s curb appeal but also extends its life and prevents costly repairs.

Here’s what you’ll learn in this guide:

  • The best products for removing moss, algae, and tough roof stains
  • How to choose the right cleaner for your roof material and stain type
  • Why working with professionals like Walsh Roofing makes a difference

🌱 Understanding Roof Contaminants

  • Moss: Moss holds moisture against shingles, which can lead to rot, mold, and premature roof failure. It grows quickly in shaded or humid areas and needs to be removed without damaging your roofing material.
  • Algae: Algae usually appear as dark streaks across the roof. It’s often mistaken for dirt or mildew, but is a specific type of airborne cyanobacteria. It thrives in moist, shaded environments and can eat away at limestone fillers in shingles.
  • Stains: Stains come from a mix of causes: algae, moss, mildew, tree debris, and pollution. Each needs a targeted approach for effective removal.

Washing the roof with a soft bristle brush

✅ Top Roof Cleaning Products to Try

Roof-A-Cide Treatment

  • EPA-approved, professionally applied formula
  • Prevents algae and mold for up to 2 years
  • Safe for all roof types, including tile and shingles

Roof-A-Cide is the only product in the U.S. that’s approved by major roofing manufacturers to prevent algae growth without damaging materials. It’s applied exclusively by certified professionals, making it ideal for long-term protection.

Wet & Forget Moss, Mold, Mildew & Algae Stain Remover

  • Safe for all roofing types
  • Non-acidic, bleach-free formula
  • Spray and leave—no rinsing required

Ideal for homeowners looking for a low-maintenance product. It works gradually over time, with wind and rain doing most of the work.

Spray & Forget Revolutionary Roof Cleaner

  • Eco-friendly, biodegradable
  • Doesn’t require rinsing
  • Works on asphalt shingles, slate, tile, and more

A popular option for environmentally conscious homeowners. Effective against mold, mildew, moss, and algae.

RMR-86 Instant Mold & Mildew Stain Remover

  • Strong commercial-grade formula
  • Works in 15 seconds or less
  • Best for stubborn mold or mildew on roof edges or fascia boards

Not ideal for general roof application, but excellent for targeted spots.

Simple Green Oxy Solve Total Outdoor Cleaner

  • Hydrogen peroxide-based, safer than bleach
  • Safe for pressure washers and manual application
  • Versatile for other home exterior surfaces too

Great if you’re doing multiple cleaning jobs in one go.

💪 Choosing the Right Product for Your Roof

after and before Roof cleaning with high pressure water cleaner tile

Asphalt Shingle Roofs

Most cleaners work well on asphalt shingles. Look for products labeled safe for this material, and avoid high-pressure washing, which can strip granules.

  • Use: Wet & Forget or Spray & Forget
  • Avoid: Harsh bleach-based cleaners or anything requiring heavy scrubbing

Tile and Slate Roofs

These materials are more brittle. You need a product that requires minimal physical pressure.

  • Use: Simple Green Oxy Solve
  • Avoid: Pressure washing and acidic cleaners

Metal Roofs

Metal roofs can usually handle stronger solutions and pressure washing when done correctly. However, rust inhibitors may be necessary.

  • Use: RMR-86 for targeted mildew; Spray & Forget for routine cleaning
  • Avoid: Products with ammonia that can cause corrosion

🧽 Application Methods That Get Results

Manual Application

Best for small jobs or spot cleaning. Requires a pump sprayer or garden sprayer.

  • Pros: Precision, control
  • Cons: Labor-intensive, slower coverage

Hose-End Sprayer

Many products come with hose-end bottles that make application easy for large areas.

  • Pros: Fast, user-friendly
  • Cons: Less precise, higher product usage

Pressure Washer (with care)

Only use this method if the product is compatible and your roof type allows it.

  • Pros: Fast cleaning, effective on tough stains
  • Cons: Risk of damage, may void warranty if misused

✅ Best Practices for Roof Cleaning

Spraying roof and cleaning algae

Safety First

Always use a roof harness or work with a professional. Slippery surfaces and uneven footing make roof work dangerous.

  • Never climb on wet or moss-covered roofs
  • Use rubber-soled shoes for grip
  • Wear protective gloves and goggles

Weather Timing

Choose a dry, cloudy day. Sun can evaporate cleaners too quickly and reduce effectiveness. Rain too soon after application can wash away the solution.

Surface Prep

Clear away branches and debris before applying any cleaner. This ensures the product makes direct contact with the stain or growth.

📋 5-Step Roof Cleaning Routine

  1. Inspect the Roof: Look for damaged shingles or flashing that might need repair before cleaning.
  2. Choose the Right Cleaner: Match the product to your roof material and problem (moss, algae, or stains).
  3. Apply Cleaner Evenly: Use a sprayer to coat the roof evenly, starting from the bottom and moving upward to avoid streaking.
  4. Let It Sit: Allow the cleaner to work. This can range from 15 minutes to several days, depending on the product.
  5. Rinse or Wait: Some products need rinsing, others don’t. Follow label instructions carefully. If needed, use a garden hose, not a pressure washer.

🤝 Why Walsh Roofing is the Team You Can Trust

Cleaning your roof isn’t just about curb appeal—it’s about protecting your investment. At Walsh Roofing, we offer expert evaluations and effective roofing services that preserve the life of your roofing system.

Our team understands the materials, chemistry, and best techniques to clean your roof without causing harm. With decades of experience serving homeowners, we offer:

  • Roof-specific product knowledge
  • Damage-free application techniques
  • Preventive recommendations to reduce future buildup

Whether you want help choosing the right cleaner or need professional roof cleaning service, Walsh Roofing is here to help. Contact us today and let us protect your home from the top down.

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