How And When Should You Remove Moss From Your Roof

How And When Should You Remove Moss From Your Roof?


February 17, 2022

When you see moss growing on your roof, you might think it looks pretty or charming, sort of like a fairytale. But the grim reality is that it’s not something you should ignore!

Why is moss on the roof bad?

Moss is wet and if you leave it to grow on your roof it will cause your roof to be damp all the time, which can cause damage to it.

There are other reasons why moss should not be allowed to take hold of your roof. Let’s explore everything you need to know about moss growth and how to go about removing it. 

Why Does Moss Grow On Your Roof? 

How And When Should You Remove Moss From Your Roof

You might have noticed that moss doesn’t form all over your roof, but rather only on certain parts of it. Why is this the case?

Moss is more likely to grow in cool, damp areas that aren’t in much sunlight. This is why north-facing roofs are prone to moss growth.

Moss also thrives when there’s organic debris. You have to ensure you clean your roof regularly so that you don’t give moss a chance to grow. 

If ignored, moss can quickly spread between and underneath your shingles, roof tiles, or slate roof. 

The Three Types Of Moss

There are three main types of moss that you’ll find growing on your roof. 

Roly-Poly Moss

This is moss that grows beneath the roof shingles and it can cause them to become raised. You’ll spot it growing at the ends of tile shingle, asphalt, or shake roofs. It’s bright green in color.

Spindly Moss

This is moss that’s a little more difficult to see on your roof, which is why you should inspect your roof regularly. It can become rooted into the shingle and cause it to deteriorate over time.

Furry Moss

This type of moss is seen on tile and wood roofs, but mostly on wood. It usually has leaves and loves to grow on rotting wood so it tends to appear when you already have damage. 

How Much Moss Is Problematic For Your Roof? 

How And When Should You Remove Moss From Your Roof

Although moss can be a problem, you don’t have to panic if you notice a tiny amount of it. It becomes a problem if you see it spreading. Then you need to do something to treat and remove it, otherwise your roof could experience problems. 

Moss absorbs moisture so whenever it rains the moss will take up that moisture and spread it across your roof shingles. It basically degrades the shingles’ protective layer in this way. Over time, the dampness will destroy your shingles and you’ll be in a position where you have to replace your roof! 

Moss also poses other dangers for your roof.

  • It can blanket parts of your roof, trapping moisture that can lead to mold, bacteria, and rot. This attracts pests while also causing your roof to deteriorate.
  • It slips underneath the roof shingles, slates, and tiles. This removes them from the roof and causes them to become damaged. It exposes the shingles to holes and leaks, which will have to be repaired. 

How To Remove Moss From Your Roof 

How And When Should You Remove Moss From Your Roof

While you can find products online that specifically target moss growth, you can make your own solution by mixing together water with chlorine bleach and spraying it onto the moss. With that in mind, here are the steps to follow to remove moss from your roof.

Step 1: Take Some Safety Precautions

To ensure you stay safe, make sure you place a secure ladder next to the area of moss. Wear slip-resistant shoes, rubber gloves, old clothes that you don’t mind getting ruined, and eye protection. Whenever you get up on the roof, you should consider wearing a safety harness to keep you secured in case you fall.

Step 2: Spray The Moss With Water

Use a low-pressure water setting to wet the moss. This will prevent you from damaging the roof shingles. A good tip is to spray the water at a downward angle.

Step 3: Scrape It With A Brush

You can start scrubbing away at the moss right away once you’ve wet it, but make sure you use a long-handled brush that has soft bristles so you won’t damage your roof. Scrub the moss from the top down – this is important so that you avoid lifting the roof shingles.

It’s also good to work on small areas of moss at a time as this will help you to have better control of the brush and not miss any spots. 

Step 4: Mix Together Bleach And Water

Mix together 1 ½ cups of chlorine bleach in 2 gallons of water. If you don’t want to use bleach there are other DIY solutions you can make. You can mix 1 ½ cup of distilled vinegar with 2 gallons of water, or 8 ounces of dish soap with 2 gallons of water. 

Once you’ve applied the moss-killing solution, let it sit for half an hour. 

Step 5: Scrub The Moss Again

After the solution has had a chance to set, you can scrub the moss again to eliminate it. 

Extra tips to bear in mind: 

  1. If you’re using a bleach solution to kill moss or you’ve purchased a product from the store, make sure you cover your nearby plants with plastic sheeting. It’s also a good idea to hose them down with water when you’ve completed your job as this will dilute any chemicals that could have fallen from the roof eaves and reached the ground.  
  2. If you want to use a power washer to remove moss from your roof, you can only do this if your roofing materials are in good condition. If your shingles or tiles are broken, damaged, or chipped in any way, the force of water can easily damage them and require you to replace your roof. Note that when you want to use a power washer on your roof, you will have to stand on the roof so you can direct the water in a downward direction. This is more dangerous, so don’t attempt it if you don’t feel confident on the roof. 

What About Powder Vs. Liquid Moss-Killing Products? 

How And When Should You Remove Moss From Your Roof

You can find a variety of products that kill moss, and these can come in the form of dry powder or liquid.

Powder: These products have to be sprinkled in lines that are parallel to the roof ridge and then when it rains the water will mix with the powder. The problem is that it’s difficult to evenly spread the powder on the roof and you have to go up on the roof to determine where the moss is and how extensive it is.

Windy conditions can also remove the powder before it has a chance to work.

Liquid: These products come in a convenient container you attach to a garden hose and then spray onto the moss. You can apply them from the ground, which is more convenient.

Moss products can turn the moss brown, which makes the moss easier to remove. To do this, you should use a long-handled brush with soft bristles.

How Do You Prevent Moss From Growing On Your Roof In Future? 

How And When Should You Remove Moss From Your Roof

To prevent moss from growing on your roof in future, you should install strips of sheet metal that’s been coated with zinc or copper below the top ridge of both sides of your roof. These metals are toxic to both algae and moss.

Purchase them in rolls and cut them into strips that are between two and four inches. With the use of screws or nails and rubber washers, secure the metal strips onto the roof. 

Other things you can do to prevent moss from growing on your roof include the following:

  • Prune your trees. If you have trees that are growing within close proximity to your roof, you need to ensure you prune them regularly. This will prevent them from producing shade over the roof which can cause moss to grow. 
  • Clear away tree debris. If there are some leaves or branches on the roof, you should remove them because these can be the perfect opportunity for moss to grow. 
  • Clean your gutters. If your gutters are clogged with debris, this can cause rainwater to overflow. By cleaning them regularly, they will drain properly and prevent dampness that attracts moss.

Is moss more common on asphalt shingles? 

Asphalt and wood roofs are more susceptible to moss because of how moss easily grips the material with its small roots. 

Does moss grow easier on a low-slope roof?

If the roof has a low-slope design, this can cause moisture and organic debris to accumulate, both of which are the perfect conditions for moss to grow. 


How and when should you remove moss from your roof? If you have noticed some green spots on your roof, you could be dealing with moss.

In this article, we’ve looked at why you have to remove moss as soon as it grows in order to protect your roof and keep it in good condition. We’ve also featured easy tips on how to remove moss from your roof without having to call the pros.

Reference Articles:


James Weldon is a professional roofing contractor with many years of experience on the job. He does not only handle large projects and provide excellent services for his company’s many clients; James Weldon also dedicates his spare time to teaching others useful tricks of the trade. Using BuildCampus as an avenue to reach many roofers and aspiring roofing contractors, James Weldon continues to provide high-quality educational posts and buying recommendations for anyone who visits the website.