Best Spray for Moss on Roof: 10 Killers, Cleaners and Zinc Strips Compared

Before you pick a product, a word on the roof itself. Climbing a wet, mossy roof is risky, and scraping or blasting moss off with a pressure washer is something many roofers advise against. Most of the products below are made so you can treat moss from the ground with a hose or a pump sprayer.

Once you decide to spray, the choices split into three groups. Ready sprays like the Scotts MossEx 3-in-1 Ready Spray 32 oz and Moss Out for Roofs 27 oz attach to a hose. Concentrates like the Spray and Forget Roof Cleaner 1 Gallon and Wet and Forget Outdoor Concentrate 64 oz are mixed in a sprayer and clean slowly. Zinc strips like the LOSTRONAUT 55 ft Zinc Strip do not kill anything, they slow regrowth after a cleaning.

We compared 10 products by type, size, coverage and application, using only listing details. Wet down nearby plants, keep runoff away from ponds and streams, and read each label for roof types before you start.

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On this page

1. Compare Moss Sprays for Roofs by Type, Size and Coverage
2. Detailed Reviews: Best Spray for Moss on Roof
3. Do Not Expect Dead Moss to Vanish Overnight
4. Protect Plants, Gutters and Runoff Before You Spray
5. How to Choose a Roof Moss Spray
6. Which Roof Moss Spray Should You Choose?
7. Frequently Asked Questions
8. Final Verdict

Compare Moss Sprays for Roofs by Type, Size and Coverage

Detailed Reviews: Best Spray for Moss on Roof

1. Scotts MossEx 3-in-1 Ready Spray, 32 fl. oz., Hose-End Applicator (Best overall hose-end moss spray for roofs)

• 32 fl ozSize
• 500 sq ftCoverage
• Hose-endApplicator
• Non-stainingListed

Best for: roofs, patios and lawns where you want a spray you can reach from the ground

Why it ranks #1: It lists roofs, a coverage figure and a hose-end applicator that keeps you off the ladder.

Scotts lists a fast-acting liquid in a 32 fl oz container that you connect to a garden hose and spray. The listing says it kills moss, algae, lichens and liverworts within hours, does not stain concrete or other surfaces, and treats up to 500 sq ft.

It names roofs, patios, decks, sidewalks, lawns and ornamental gardens, and says you can use it any time of year. Read the label for roof types and rinse rules.

Skip it if you want a cleaner for black streaks; the Spray and Forget Roof Cleaner 1 Gallon lists those.

2. CENTRAL GARDEN BRANDS Moss Out Roofs, 27-Ounce, Hose End Sprayer (Best made-for-roofs moss killer)

• 27 ozSize
• 500 sq ftCoverage
• 25 ftSpray reach
• Non-stainingShingles

Best for: asphalt and other shingle roofs that you can reach with a hose

Why it ranks #2: It is the one listing built specifically for roofs, with a stated spray reach.

The listing says this product is specially made for roofs, does not stain or damage shingles and covers up to 500 sq ft. An included hose nozzle sprays up to 25 ft.

The listing gives no active ingredient. Check the label for roof types, weather and rinsing steps.

Skip it if you want a bigger volume; the Spray and Forget Roof Cleaner 1 Gallon makes 10 gallons.

3. BioAdvanced 2-in-1 Moss and Algae Killer and Cleaner, Ready-to-Spray, 32 oz, 500 SQ FT (Best for killing and protecting for months)

• 32 ozSize
• 500 sq ftCoverage
• MonthsProtection
• 2-in-1Killer and cleaner

Best for: roofs, decks and driveways where you want protection afterward

Why it ranks #3: It lists protection for months, though dead moss must still be removed.

BioAdvanced lists a ready-to-spray moss and algae killer and cleaner that kills moss, algae, lichen, mold and mildew within hours and protects for months. It names lawns, patios, roofs, buildings, decks, driveways and mulch.

The listing says moss turns yellow and then brown, but it must be physically removed once dead. It does not state how long exactly protection lasts.

Skip it if you want a roof-only product; the Moss Out for Roofs 27 oz is made for roofs.

4. Lilly Miller Moss Out! For Roofs and Structures Dry Formula 6 Pounds (Best dry moss killer for roofs and structures)

• 6 lbSize
• Micro-granuleForm
• Non-stainingListed
• Galvanized guttersNon-corrosive

Best for: roofs and structures where you want a dry product and gutter-safe wording

Why it ranks #4: It is the only dry formula here and notes it is non-corrosive to galvanized gutters.

Lilly Miller lists an exclusive micro-granule formula that kills moss quickly. It names roofs, patios, sidewalks, brick and unpainted cement, wet or dry.

The listing says it is non-staining and non-corrosive to galvanized gutters. It does not give a coverage figure, so check the label.

Skip it if you want a spray from the ground; the Scotts MossEx 3-in-1 Ready Spray 32 oz is a hose-end spray.

5. Wet and Forget Moss, Mold, Mildew and Algae Stain Remover Multi-Surface Outdoor Cleaner Concentrate, 64 Fluid Ounces (Best no-scrub, no-rinse cleaner concentrate)

• 64 fl ozSize
• 1 to 5Mix ratio
• 375 to 1,125 sq ftOne bottle
• Bleach freeListed

Best for: roofs, siding and decks where you can wait for rain to clean over time

Why it ranks #5: It cleans slowly with wind and rain and needs no rinsing, but results take weeks to months.

Wet and Forget lists a concentrate that you dilute 1 part product to 5 parts water and spray on a dry, debris-free surface. It says not to rinse and not to apply when rain is expected within 4 to 5 hours.

The listing says green stains clear in 1 to 2 weeks, black stains can take several months and long-established stains may take 6 to 12 months. It is bleach free and non-acidic and should be sprayed 100 ft from lakes and streams.

Skip it if you want quick color change; the Spray and Forget Roof Cleaner 1 Gallon lists minutes.

6. Spray and Forget 1-Gallon Concentrated Roof Cleaner (Best for black streaks across a larger roof)

• 1 galSize
• 10 galMakes up to
• 1000 to 2000 sq ftCoverage
• 1 to 9Mix ratio

Best for: larger roofs with black streaks, algae and mildew stains

Why it ranks #6: It makes the most solution per bottle and lists asphalt, wood, slate, clay and tile.

Spray and Forget lists a bleach and phosphate-free concentrate that makes up to 10 gallons, enough for 1000 to 2000 sq ft. The mix is 1 part product to 9 parts water. The listing says most stains turn orange after at least 10 minutes.

It is for shingles including asphalt, wood, slate, clay and tile, and visible results get better over time. It removes black streaks and stains from algae, mold and mildew. Follow label rinsing steps.

Skip it if you want a moss-named spray; the Scotts MossEx 3-in-1 Ready Spray 32 oz names moss.

7. Spray and Forget 1-Quart Hose End Concentrated Roof Cleaner (Best hose-end cleaner for a second story)

• 1 qtSize
• 400 to 600 sq ftCoverage
• 2nd storyReach
• Eye and skin irritantWarning

Best for: mid-size roofs where you want a hose attachment

Why it ranks #7: It reaches a second story with a hose, and the listing warns about eye and skin contact.

Spray and Forget lists a super concentrated hose-end roof cleaner that removes black streaks and stains from algae, mold and mildew. The listing says it reaches the second story and treats 400 to 600 sq ft.

It names asphalt, wood, slate, clay and tile shingles. The listing says to wet landscaping before and after, wear eye protection and chemical resistant gloves and wash after handling.

Skip it if you want a large mix batch; the Spray and Forget Roof Cleaner 1 Gallon makes 10 gallons.

8. ROOF CLEANER 1G, removes algae, mold, mildew, moss and lichen, no rinsing, makes up to 10 gal (Best no-rinse concentrate by title)

• 1 galSize
• 10 galMakes up to
• 1000 to 2000 sq ftCoverage
• No rinsePer title

Best for: a larger roof where a concentrate is more economical in volume

Why it ranks #8: Its listing has no feature text, so only the title can be confirmed.

The title says this roof cleaner removes algae, mold, mildew, moss and lichen, needs no rinsing, makes up to 10 gallons and covers 1000 to 2000 sq ft. It has no feature bullets.

Read the label for the mix ratio, roof types and safety steps.

Skip it if you want written details; the Spray and Forget Roof Cleaner 1 Gallon lists the mix ratio.

9. LOSTRONAUT 55 Ft Zinc Strip for Roof Moss Control 2.5 in Wide (Best zinc strip for prevention)

• 55 ftLength
• 2.5 inWidth
• ZincMetal
• 20+ yearsMaker claim

Best for: preventing moss on a roof that has been cleaned

Why it ranks #9: It is a prevention strip, not a spray, and works as rain washes zinc down the roof.

LOSTRONAUT lists a zinc metal roll that the listing says spreads zinc when it rains to halt growth on roof panels. Install with roofing nails with neoprene washers and construction adhesive.

The listing says to add more rows for shady spots, that it suits most roofing materials, and that it is designed to last over 20 years. That lifespan is the maker claim.

Skip it if you need to kill moss now; the Scotts MossEx 3-in-1 Ready Spray 32 oz is a spray.

10. Zinc Protect Roof Strip for Moss and Mildew Prevention, 2.5 in Wide and 50 ft Long (Best alternate zinc strip)

• 50 ftLength
• 2.5 inWidth
• ZincMetal
• PreventionUse

Best for: preventing moss and mildew after a cleaning

Why it ranks #10: Its listing has only a title, so little can be confirmed beyond size.

The title gives a 50 ft by 2.5 in zinc strip sold for roof moss and mildew prevention. The listing has no feature bullets.

Use the product page and roofing guidance for installation, nailing and spacing.

Skip it if you want a longer listed roll and install notes; the LOSTRONAUT 55 ft Zinc Strip lists 55 ft and nailing steps.

Do Not Expect Dead Moss to Vanish Overnight

A killer turns moss yellow and then brown, but the dead growth stays put. The BioAdvanced 2-in-1 Moss and Algae Killer 32 oz listing says it must be physically removed once dead, and the Scotts MossEx 3-in-1 Ready Spray 32 oz lists results within hours, not a clean roof. Plan on a gentle brush or on rain to clear it, and do not scrub hard on shingles.

Cleaners like the Wet and Forget Outdoor Concentrate 64 oz work the other way. They are sprayed on and left, and the listing says green stains clear in 1 to 2 weeks while black stains can take months. Choose by how long you can wait.

Protect Plants, Gutters and Runoff Before You Spray

Roof products run down into gutters and onto the beds below. The Spray and Forget Hose End 1 Quart listing says to wet landscaping before and after and to wear eye protection and chemical resistant gloves. The Wet and Forget Outdoor Concentrate 64 oz listing says to spray 100 ft from lakes and streams.

If your gutters are galvanized, note that the Lilly Miller Moss Out Dry 6 lb listing calls it non-corrosive to galvanized gutters. Check the label of any product for roof types, weather limits and rinse steps, and for local rules on runoff.

How to Choose a Roof Moss Spray

Type

Ready sprays like the Scotts MossEx 3-in-1 Ready Spray 32 oz and BioAdvanced 2-in-1 Moss and Algae Killer 32 oz need no mixing. Concentrates like the Spray and Forget Roof Cleaner 1 Gallon and Roof Cleaner 1 Gallon No-Rinse make up to 10 gallons. A dry formula like the Lilly Miller Moss Out Dry 6 lb is spread by hand.

Coverage

Ready sprays here list about 500 sq ft per bottle. Concentrates list 1000 to 2000 sq ft, like the Spray and Forget Roof Cleaner 1 Gallon. Measure your roof before you buy.

Application

A hose-end like the Moss Out for Roofs 27 oz sprays up to 25 ft. The Spray and Forget Hose End 1 Quart reaches a second story. Pump sprayers suit the concentrates.

Prevention

Zinc strips like the LOSTRONAUT 55 ft Zinc Strip and Zinc Protect 50 ft Roof Strip work as rain carries zinc down the roof. They go along the ridge and are best added after a cleaning.

Which Roof Moss Spray Should You Choose?

• If you want a hose-end spray that names roofs and lawns, choose the Scotts MossEx 3-in-1 Ready Spray 32 oz, because it covers 500 sq ft.
• If you want a product made for roofs, choose the Moss Out for Roofs 27 oz, because it sprays up to 25 ft.
• If you want protection afterward, choose the BioAdvanced 2-in-1 Moss and Algae Killer 32 oz, because it lists months of protection.
• If you prefer a dry product, choose the Lilly Miller Moss Out Dry 6 lb, because it is a micro-granule formula.
• If you can wait for rain, choose the Wet and Forget Outdoor Concentrate 64 oz, because it needs no scrubbing or rinsing.
• If you have black streaks on a large roof, choose the Spray and Forget Roof Cleaner 1 Gallon, because it makes up to 10 gallons.
• If you have a second story, choose the Spray and Forget Hose End 1 Quart, because it is a hose-end that reaches it.
• If you want a no-rinse concentrate, choose the Roof Cleaner 1 Gallon No-Rinse, because its title says so.
• If you want to prevent regrowth, choose the LOSTRONAUT 55 ft Zinc Strip, because it is a 55 ft zinc strip.
• If you want a second zinc option, choose the Zinc Protect 50 ft Roof Strip, because it is a 50 ft strip.

Frequently Asked Questions

What is the best spray for moss on a roof?

For most roofs, the Scotts MossEx 3-in-1 Ready Spray 32 oz is the best pick here, a 32 fl oz hose-end spray that covers 500 sq ft and names roofs. The Moss Out for Roofs 27 oz is the one made specifically for roofs.

Is it safe to spray moss killer on a roof?

Read the label first for roof types, weather and rinse steps. Wet nearby plants, wear gloves and eye protection as the Spray and Forget Hose End 1 Quart listing advises, and keep runoff away from water. This is general guidance, not a substitute for the label.

Do I need to remove dead moss?

Often yes. The BioAdvanced 2-in-1 Moss and Algae Killer 32 oz listing says dead moss must be physically removed. Rain may clear some of it over time.

How long do roof cleaners take to work?

It varies. The Scotts MossEx 3-in-1 Ready Spray 32 oz lists results within hours, while the Wet and Forget Outdoor Concentrate 64 oz lists 1 to 2 weeks for green stains and several months for black stains.

Do zinc strips kill moss?

No. The LOSTRONAUT 55 ft Zinc Strip listing describes zinc spreading down the roof when it rains to halt growth. It prevents regrowth rather than cleaning existing moss.

Should I use a pressure washer on a mossy roof?

Many roofers advise against it, so check with your roof maker or a roofer. The sprays here are designed to be applied from the ground with a hose or sprayer.

Final Verdict

The Scotts MossEx 3-in-1 Ready Spray 32 oz is the best spray for moss on a roof in this guide. It is a 32 fl oz hose-end spray that names roofs, covers 500 sq ft and keeps you off the ladder. If you want a roof-only product, the Moss Out for Roofs 27 oz is the alternative. Before you spray, protect nearby plants, read the label and plan to remove the dead moss afterward.

See the Scotts MossEx 3-in-1 Ready Spray 32 oz on Amazon