7 Best Chemical Roof Cleaners 2025 in the United States

The Wet & Forget Outdoor Moss, Mold, Mildew, & Algae Stain Remover is a versatile chemical cleaner designed for a wide range of outdoor surfaces, including roofs. One of its main strengths is the new & improved nozzle that attaches to a garden hose, allowing you to spray up to 30 feet high, which is particularly useful for hard-to-reach areas.

The product's application is straightforward: spray on a dry, cool day and let it work over time with natural elements like wind and rain – no rinsing required. However, the time it takes to see results can vary significantly. While green stains may disappear within a couple of weeks, more stubborn black stains could take several months, and long-established stains might need up to a year to fully clean. This extended timeline might be a drawback for those looking for quick results.

Safety-wise, the cleaner is bleach-free and non-acidic, making it safer for use around plants and animals if proper precautions are taken. However, it’s advised to keep it away from bodies of water and to flush plants with water before and after application. With a coverage of up to 2,000 square feet per bottle, it offers good value, but heavily stained or porous surfaces may absorb more product, reducing its effective coverage.

The cleaner is ideal for homeowners looking for a long-term solution to moss, mold, mildew, and algae stains on various surfaces, including roofs, driveways, and decks. It is not suitable for those needing an immediate cleaning solution.

The Wet & Forget Moss, Mold, Mildew, & Algae Stain Remover is a versatile concentrate outdoor cleaner designed to tackle stains on various hard, sealed non-porous surfaces, including roofs, driveways, patios, and more. One of its major strengths is the ease of use, as it requires no scrubbing or rinsing—just apply it and wait for nature to do the rest. This can be a big time-saver for users who have large areas to clean.

The product is also bleach-free and non-acidic, making it safer for use around plants when proper precautions are taken, such as flushing plants with water before and after application. However, it is essential to use it away from bodies of water to minimize environmental impact. The mixture ratio is straightforward: dilute one part of the concentrate with five parts water and apply using a garden sprayer.

It is effective over time, with green stains typically clearing up within 1-2 weeks, while more stubborn black stains can take several months to disappear, which may require patience from the user. Long-established stains may take up to a year, so it might not be suitable for those seeking immediate results. Coverage is another strong point, as one bottle can treat between 375 to 1,125 square feet, though heavily stained or porous surfaces will require more product. This product is excellent for those looking for a low-effort cleaning solution with long-term effectiveness, but it may not be ideal for users needing rapid results.

Wet & Forget Outdoor Moss Mold Mildew & Algae Stain Remover is a liquid concentrate designed for removing a range of common outdoor stains including moss, mold, algae, and mildew from roofs and other surfaces. Its biggest strength lies in its easy application method: you dilute it with water, spray it on dry surfaces, and then simply wait without scrubbing or rinsing. This makes it very convenient for homeowners who prefer a low-maintenance approach.

The cleaner works gradually, with lighter green stains fading within a couple of weeks, while tougher black or old stains can take several months to disappear. This slow but steady action means it’s not a quick fix, but it helps keep surfaces cleaner for up to a year. Safety-wise, the product is bleach-free and non-acidic, reducing risk to roofing materials like vinyl, wood, aluminum, and sealed concrete. It’s important to apply it away from water sources and protect plants by rinsing them before and after treatment, showing some environmental caution. It covers a wide area per container, which is good value for larger roofs or multiple surfaces.

The need to avoid rain for several hours after application and the long wait for results might not suit those looking for immediate cleaning effects. Additionally, since it relies on rain and wind for rinsing, its performance depends on weather conditions, which can be unpredictable. This product is ideal for users seeking a gentle, no-scrub solution for maintaining roofs and outdoor surfaces over time without harsh chemicals. It suits those patient enough for gradual results and careful about protecting nearby plants and water sources during application.