Rising algae and moss on shingles and roofs is a common issue for American homeowners. The right cleaner can remove black algae stains and green growth without harsh scrubbing or pressure washing. Below you’ll find five proven roof cleaners that target black algae, mold, and mildew while being suitable for multiple exterior surfaces. Each product listing includes key features and practical application tips to help you choose the right formula for your roof and climate.
Summary of selected products:
| Product | Brand | Size | Key Benefit |
|---|---|---|---|
| Wet & Forget Moss, Mold, Mildew, & Algae Stain Remover Multi-Surface Outdoor Cleaner Concentrate | Wet & Forget | 128 Fl Oz | No scrubbing or rinsing; long-lasting cleanliness |
| Wet & Forget Outdoor Moss, Mold, Mildew, & Algae Stain Remover Multi-Surface Cleaner, Xtreme Reach | Wet & Forget | 48 Fl Oz | Extended reach; gradual cleaning with weather |
| Spray & Forget 1-Quart Hose End Concentrated Roof Cleaner | Spray & Forget | 1 Quart | Hose-end convenience; deep stain removal |
| RMR-86 Instant Mold and Mildew Stain Remover Spray | RMR Brands | 1 Gallon | Instant stain removal on multiple surfaces |
| Spray & Forget 1-Gallon Concentrated Roof Cleaner | Spray & Forget | 1 Gallon | Fast-acting concentrate for large areas |
Wet & Forget Moss, Mold, Mildew, & Algae Stain Remover (128 Oz)
Wet & Forget Concentrate Outdoor Cleaner is designed to remove green and black stains from moss, mold, mildew, and algae without scrubbing, rinsing, or pressure washing. It’s suitable for roofs, driveways, siding, and more. The product is mixed 1 part concentrate to 5 parts water and should be applied to a dry surface on a cool day. Do not rinse, and avoid applying within a forecast window of rain within roughly 4–5 hours. This low-effort approach can yield long-lasting results as wind and rain continue the cleaning process over time.
Wet & Forget Outdoor Moss, Mold, Mildew, & Algae Stain Remover (Xtreme Reach)
The Xtreme Reach Hose End version uses a garden hose for application and can spray up to 30 feet, enabling easier coverage of roofs and higher surfaces. It cleans green and black algae stains on roofs and siding with a fan tip for driveways and decks. As with other Wet & Forget products, there is no rinsing required, and application timing matters—spray on a cool day and avoid rain within 4–5 hours. Expect gradual improvement over 1–2 weeks for green stains and longer for black, stubborn stains.
Spray & Forget 1-Quart Hose End Concentrated Roof Cleaner
Spray & Forget’s Roof Cleaner is a concentrated formula designed for roof shingles—whether asphalt, wood, slate, clay, or tile. The hose-end bottle can reach the second story and treats approximately 400–600 square feet. The product aims to remove black streaks and other stains caused by algae, mold, and mildew, with visible improvements happening over time. It’s a convenient option for homeowners who prefer a spray-and-go approach without scrubbing.
RMR-86 Instant Mold and Mildew Stain Remover Spray (1 Gallon)
RMR-86 is a professional-strength spray formulated to eliminate mold and mildew stains on a variety of surfaces, including decks, wood, vinyl siding, drywall, concrete, brick, and kitchen surfaces. The product is designed for quick, scrub-free stain removal, but users should follow ventilation and PPE recommendations during application. RMR-86 provides strong effectiveness for deeply embedded stains, making it a popular choice for stubborn roof and outdoor surfaces.
Spray & Forget 1-Gallon Concentrated Roof Cleaner
This concentrated roof cleaner from Spray & Forget targets black streaks and other stains caused by algae, mold, and mildew. It’s designed to work fast, delivering noticeable results in minutes rather than weeks, and is suitable for use on shingles, including asphalt, wood, slate, clay, and tile. It’s a scalable option for larger roof areas given its gallon-size concentrate that can be mixed for broad coverage.
Buying Guide: Key Considerations For Choosing A Black Algae Roof Cleaner
When selecting a roof cleaner for black algae and related stains, consider the following factors to ensure a good match for your roof type, climate, and maintenance goals.
- Surface compatibility: Confirm the cleaner’s suitability for roof shingles and other exterior surfaces like wood, vinyl, concrete, and metal. Some products are multi-surface while others are rooftop-focused.
- Application method: Hose-end concentrates, concentrate sprays, and ready-to-use formulas have different labor and reach requirements. Consider your access to water, the height of your roof, and whether you prefer scrubbing-free solutions.
- Stain depth and type: Black stains from established mold or mildew can take longer to remove. Products labeled for “instant” stain removal may perform differently on persistent stains.
- Weather and timing: Most products require dry, cool conditions and advise avoiding rain within several hours of application. Consider your local climate and seasonal timing.
- Safety and PPE: Some cleaners require ventilation and personal protective equipment (PPE). Follow label instructions for safe use, especially in enclosed or windy areas.
- Long-term maintenance: Several cleaners claim long-lasting results that can keep roofs cleaner for months to a year. Evaluate whether a maintenance plan or repeat treatments fit your expectations and budget.
- Environmental impact: Check for phosphate-free or biodegradable formulations if environmental concerns are a priority.
- Coverage and cost efficiency: Compare coverage areas per gallon or per bottle, and assess how often reapplication is recommended for your roof size.
Across these options, homeowners typically weigh ease of use against speed of results. Hose-end and spray-applied formulas offer convenience for higher or hard-to-reach areas, while concentrate products can be cost-effective for large roofs when you’re comfortable mixing and applying manually. For stubborn or deeply embedded stains, pairing a strong cleaner with repeated applications over time often yields the best outcome. Always follow product-specific directions for safety, surface preparation, and timing to optimize results.