7 Best Roof Cleaning Chemicals 2026: Restore Your Shingles
Stop unsightly black streaks and damaging moss. We reviewed the top-rated cleaners, from “spray and forget” solutions to professional-grade concentrates.
Have you noticed ugly black streaks running down your roof? That isn’t just dirt—it’s a cyanobacteria called Gloeocapsa Magma. Left unchecked, along with moss and lichen, these organisms eat away at the limestone filler in asphalt shingles, potentially shortening the lifespan of your roof.
The solution isn’t high-pressure washing, which can blast away the protective granules on your shingles. The solution is soft washing using the right chemicals. In this guide, we break down the 7 best roof cleaning chemicals that kill the infestation at the root, restoring your home’s curb appeal and protecting your investment.
Understanding the Chemistry: Bleach vs. Non-Bleach
Before buying, you need to know what you are spraying.
- Sodium Hypochlorite (Bleach): The “nuclear option.” It works instantly on black streaks and algae. However, it can kill plants if not rinsed properly and requires careful handling.
- Sodium Percarbonate (Oxygen Bleach): A safer, bubbling cleaner that is effective on moss and lichen but works slower than chlorine bleach.
- Benzalkonium Chloride (Alkyl Dimethyl Benzyl Ammonium Chloride): The active ingredient in “leave-on” cleaners. It kills over time with the help of rain. Safest for the roof surface but requires patience.
If you are dealing with heavy moss growth, chemical treatment is only step one. You may need to manually remove dead moss later. See our guide on how to get rid of moss on a roof for the full process.
Wet & Forget Xtreme Reach Hose End
The “Lazy” Homeowner’s Dream. Wet & Forget is the industry leader for a reason. It uses a non-acidic, non-caustic formula that works over time. You simply spray it on and let the wind and rain do the scrubbing over the next few months.
The “Xtreme Reach” nozzle attaches directly to your garden hose and can shoot up to 30 feet, meaning you might not even need to climb a ladder for a single-story home.
Pros
- Zero scrubbing required.
- Safe for all roof types (Asphalt, Tile, Metal).
- Long-lasting residual effect prevents regrowth.
- No ladder needed for lower roofs.
Cons
- Results take weeks or months (not instant).
- Heavy moss requires physical removal first.
30 Seconds Outdoor Cleaner
Instant Gratification. If you are selling your house next week and need the roof to look new today, this is the product. It uses a bleach-based formula to dissolve algae stains and mold almost immediately upon contact.
Because it is potent, you must pre-wet all surrounding vegetation and rinse thoroughly afterwards to prevent plant damage. It’s excellent for asphalt shingles and works well as a general exterior cleaner.
Pros
- Visible results in minutes.
- Attaches to garden hose.
- Very effective on black streaks.
Cons
- Contains bleach (can harm plants).
- Requires rinsing.
Wash Safe Industries Roof Wash
The Organic Choice. If you have prize-winning roses or are worried about pets, Wash Safe is the solution. It uses hydrogen peroxide (oxygen bleach) rather than chlorine. When it breaks down, it turns into water and oxygen.
It is a powder concentrate that you mix with water. It is particularly effective on lichen and moss, causing them to turn white and detach from the roof. It is safe for asphalt and cedar shake roofs.
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Spray & Forget Revolutionary Roof Cleaner
Similar to Wet & Forget, this is a leave-on product. However, it is often sold as a super-concentrate that can make up to 10 gallons of cleaning solution. This makes it incredibly cost-effective for large roofs or multi-property owners.
It creates a barrier that prevents regrowth for up to 24 months in some climates. It is ideal for those who own a pump sprayer and want precise application control.
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Simple Green Oxy Solve Roof and Driveway
If you insist on using a pressure washer, use this chemical on a low-pressure setting. Simple Green uses the power of peroxide to lift grime without harsh chemicals. It is EPA Safer Choice certified.
It is designed to be fed through the detergent tank of a pressure washer. It foams up nicely, allowing the solution to cling to vertical surfaces or steep roof pitches. Afterward, you rinse it off at low pressure.
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BioAdvanced 2-in-1 Moss & Algae Killer
This is a fantastic alternative for those looking to both kill existing moss and prevent its return. It comes in a “Ready-to-Spray” bottle that attaches to your garden hose, making application incredibly easy for hard-to-reach peaks.
It uses a potassium soap of fatty acids formula which is non-staining and safe for most surfaces including roofs, decks, and siding. It excels at turning moss brown quickly, making it easier to brush off later.
Pros
- Hose-end sprayer included.
- Non-staining formula.
- Kills moss, algae, and lichen effectively.
- Bleach-free (safer for surfaces).
Cons
- Toxic to aquatic life (careful with runoff).
- Slower on black streaks than bleach.
Defy Wood Cleaner
Wood roofs are sensitive. Chlorine bleach can turn cedar shakes unnaturally white and damage the wood fibers (lignin), reducing the roof’s lifespan. Defy uses a gentle oxygen-based formula specifically designed to clean wood without bleaching the natural color.
It effectively lifts dirt, graying from UV exposure, and biological growth. It comes as a powder concentrate that you mix with water, making it a powerful solution for restoring the natural beauty of cedar shakes and shingles.
Pros
- Oxygen-based (Chlorine-free).
- Restores natural wood color (doesn’t bleach white).
- Biodegradable and safe for vegetation.
- Excellent for cedar shakes and decks.
Cons
- Requires scrubbing and rinsing.
- Powder must be mixed thoroughly.
Safety & Application Guide
Applying chemicals to a roof carries risks. Here is your checklist:
- Protect Plants: Even “safe” chemicals can stress plants. Water your garden thoroughly before and after cleaning to dilute any runoff.
- Walk Safely: Wet roofs are ice-rinks. Wear non-slip shoes. Check our guide on best roofing shoes for traction advice.
- Don’t Pressure Wash: Never use high pressure on asphalt shingles. It knocks the granules off. Use a garden hose or a soft-wash pump system.
- Check Leaks: Before spraying tons of water, ensure your roof is watertight. If you suspect issues, read how to find a roof leak first.
Once your roof is clean, consider maintaining it. Inspect your sealants and flashings. For product recommendations, see our review of the best roof sealants.
Frequently Asked Questions
Used correctly (diluted) and rinsed properly, chlorine bleach is safe for asphalt shingles and is the standard chemical used by professionals. However, leaving it on too long or using it repeatedly without rinsing can dry out the shingles and cause curling.
It depends on your climate. In humid or shaded areas, you might need to treat black streaks every 2-3 years. If you use a preventative spray like Wet & Forget, you can extend this to 3-5 years.
Yes, vinegar (acetic acid) kills moss, but it is often not strong enough to remove deep stains or heavy infestations without significant scrubbing. Commercial cleaners are generally more effective for long-term results.
No. Painting over algae or moss will trap moisture and accelerate the rot of your shingles. You must clean and kill the growth first. Some metal roofs can be painted; see can you paint a metal roof for details.