How to Kill and Get Moss Off Roofs: A Complete Guide on Moss Removal and Preventation (2023)

Moss begins its life as tiny, airborne moss spores that connect to various surfaces based on their conditions — preferably, damp zones with little ventilation for complete dryness. Through spore dispersal — by insects and the wind — what was once a small patch of moss can cover a significant area, wreaking havoc on your roof.

With rain to enhance its growth, moss continues to expand and spread across all areas, including trees, lawns, and, most commonly, rooftops.

Continue reading to learn how to remove moss from roof tiles, the wide varieties of moss killers, and keep your roof in tiptop condition.

Why Moss Grows on Roofs

Moss prospers in damp conditions, and roofs are the perfect breeding ground for life. Rooftops are typically shaded by trees or are north-facing, exposing them to little direct sunlight. Clay or concrete tiles are more prone to moss growth due to their porous surfaces and regular rain exposure.

Once moss makes a roof its home, the growth will happen quickly, especially with regular downpours and if you neglect to remove it.

Why You Should Remove Moss From Roof Tiles

Preventing a buildup of moss growth is important to avoid destruction and even roof replacement. Here are two reasons to keep your roof in check:

Roof Rot

Gathered dead moss on rooftops doesn’t look aesthetically pleasing, but it has a more significant effect than just its inattentive appearance. Moss grows at significant rates, but it doesn’t absorb water. Instead, it sits on top of moisture, leaving your roof constantly wet.

If you fail to remove the moss, rain pour can’t dispel effectively, potentially resulting in wood rot. This creates a spiral effect of other problems, such as termites and tearing through shingles, resulting in you needing a new roof.

Loose Tiles

Mass moss growth can retain water against the roof’s surface. This water can then freeze and thaw in the winter months, ripping apart tiles. Not only does this create holes in your rooftop, but it’s also a huge safety issue should tiles fall off.

What to Use: Types of Roof Moss Killers

A store-bought roof moss killer stops moss growing in its tracks, and there are a couple of types to look out for.

Liquid Roof Moss Killers

A liquid algae killer includes a container that connects to a hose, mixing the solution with the water. Liquid roof moss killers engulf the entire roof evenly (more so than dry powders). They’re also a safer application, as your hose might reach the roof without you having to get up there. Or, worst-case scenario, you just need to stand on a ladder to reach.

The one disadvantage of this type of roof moss killer is keeping track of your application. To avoid repeating the same section, you’ll need to mentally monitor where you apply it. Starting with a dry roof is also a big help with this.

When looking for a liquid moss killer, opt for one that’s non-corrosive to metal and, ideally, has a spray nozzle for even application.

Dry Roof Moss Killers

These have a slower killing time (up to a week), and they require you to get onto the roof to sprinkle the powder in all the affected areas. However, once you’re in position, the application is less stressful. Simply leave the powder and allow the rain to mix the solution toward the eaves.

It’s also worth bearing in mind that if it doesn’t rain, you’ll need to direct your hose onto the roof. Plus, any gust of wind can blow away the powder, so you’ll have to repeat the application.

Homemade, Natural, & DIY Roof Moss Killers

Tackle moss without the expense and harsh chemicals by switching to a homemade alternative. Here are two DIY recipes to try:

Recipe 1

• 1 gallon warm water
• 1 tbsp vinegar
• 1 lb salt
• Dish soap

Instructions

• Combine all of the ingredients and add soap to absorb
• Pour the mixture into a spray bottle, and apply it to the moss to dampen it
• Leave for two-three days, and scrape away the moss with a scrub brush

Recipe 2

• 5 gallons water
• 3 oz iron sulfate

Instructions

• Mix the ingredients in a bucket, and pour it into a spray bottle
• Shower the moss with the solution and leave for three-four days
• Loosen the moss with a brush or rake
• Wash away with water

For any of these moss-killer methods, warmer weather is best, allowing the water to dry.

Safety and Restrictions

Regardless of the moss killer you purchase, you’ll need to get close to the roof, if not on top of it. Here’s how to stay safe:

• Don’t attempt to clean moss off of your roof in slippery weather
• Don’t wear loose clothing
• Consider a harness to secure you to the roof, giving you peace of mind that it’ll protect you if you fall
• Ask for assistance to support a ladder
• Wear shoes with a grip
• Avoid distractions (turn your phone on silent, don’t talk to neighbors, etc.)

How to Remove Moss from Roofs

It’s time to stop the never-ending cycle of moss with steps and applications that will kill it.

Project Duration

Depending on the amount of moss and its persistence, the entire removal process can take up to several hours.

Tools and Materials Required

You’ll need:

• Moss killer
• Ladder
• Garden hose
• Brush
• Scrub brush
• Safety goggles
• Rubber gloves

Moss Removal Steps

1. Get onto the roof

• Wear a harness and have an assistant hold a ladder and climb onto the roof.

2. Remove any debris from your roof

• Take a long-handled brush to wipe away any debris on the roof as well as any moss.

3. Hose the roof

• Take a hose (not a pressure washer), and spray your roof at a downward angle.

4. Scrub the moss

• Use a soft-bristle brush to remove any visible moss, scrubbing downward, so the moss doesn’t remain on the roof.
• Work in small sections and don’t press down on the roof tiles too hard to keep them intact.

5. Apply your commercial or homemade cleaner

• Douse the roof in your chosen moss killer, ensuring that you carefully read the instructions.
• Bear in mind that many solutions can damage plants, and pathways, so you may need to use plastic sheeting to protect such areas.

How to Clean Your Roof After Removing Moss

Once there’s no more moss present, there are several strategies to keeping your roof clean. This will help to keep moss at bay, reduce decay, improve your roof’s appearance, increase its lifespan, and, potentially, add value to your home.

Avoid Pressure Washing and Harsh Chemicals

Pressure washing can make tiles more porous, increasing dampness for moss to grow. Also, harsh chemicals — like chlorine bleach — can weaken tiles and even cause harm to the landscape and surrounding nature.

Instead, switch to a powerful setting on a hose to target moss areas. Ideally, use as little water as possible to prevent damp areas, and clean your roof on a sunny day for better moisture absorption.

Scrape Any Remaining Moss

Likely, there are still some moss particles present on your roof. So you might need to get up close and use a scraper to remove anything leftover. Take considerable care not to damage the tiles. Additionally, a brush can remove any remaining debris.

How to Prevent Moss Growth on Roofs

Prevention is better than cure, so here’s how to tame moss growth in the first place:

Trim Trees

The best way to stop moss from forming on your roof is to expose your roof to more sunlight. You can’t rotate your house or manipulate the Sun’s position, but cutting back trees and branches prevents them from overhanging onto your roof. Moss doesn’t like direct sunlight, so it won’t appear in the first place.

Regular Maintenance

It’s easy to forget about your roof’s condition and appearance. However, regularly remove branches, twigs, and debris to prevent any restrictions for rain pour to dissipate. You should also keep your gutters free from leaves and sticks to prevent dampness. A dry, sunlit rooftop won’t attract moss in the first place.

Final Thoughts

Remove moss from roof tiles to prevent damage to your home and potential roof repairs. This flowerless plant is notorious for taking over roofs, impacting your home’s structure.

Frequent roof cleaning can prevent mounds of moss from appearing, and invest in a trusty moss killer to inhibit growth. Alternatively, hire a professional to tackle the job for you.

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