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Asphalt Shingle Roof | Roofing Industry Knowledge

How Do You Remove Moss from a Roof?

December 9th, 2024 | 5 min. read

How Do You Remove Moss from a Roof?

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Does your roof have moss on it? Are you trying to figure out if removing the moss is possible without causing damage?

Not only does it look bad, but moss damages asphalt shingles and leads to quicker deterioration. The good thing is that removing it from your roof in a few different ways is possible.

However, it must be done right to avoid causing serious damage. So, how do you remove moss from a roof?

For over 30 years, Bill Ragan Roofing has guided homeowners through the complexities of the roofing industry. Now, I’ll put this experience to use to help you remove moss from your roof and much more.

By the end of this article, you’ll have the answers to the following questions:

  • How do you remove moss from a roof?
  • Can you use a pressure washer to remove moss from a roof?
  • Should you clean moss off your roof yourself?
  • Can you prevent moss from growing on your roof?
  • Does moss on your roof mean you need a roof replacement?

How do you remove moss from a roof?

There are a few different ways to remove moss from a roof. You can wet the moss with a low-pressure hose to remove it by hand, but this is extremely time-consuming and dangerous.

You can also buy solutions, mixes, and powders at Home Depot and other home improvement retailers to spread on the roof. However, results and opinions on these options are mixed. 

In my opinion, the best way to remove moss from a roof is to follow the advice of shingle manufacturers by using bleach and water mixture. 

According to the Asphalt Roofing Manufacturers Association

“The most effective method of cleaning algae and moss from a roof is with a 50:50 mix of laundry strength liquid chlorine bleach and water. Apply with a sprayer and allow the solution to dwell on the roof surface for 15 to 20 minutes, and then rinse thoroughly with low pressure water.”

Just know that a bleach solution that is too strong can discolor your shingles like it does clothing. So, it’s crucial to do it correctly to avoid unsightly streaks coming down your roof. 

Can you use a pressure washer to remove moss from a roof?

The most important piece of advice I can give you is not to pressure wash your roof to clean moss off the shingles. This will damage the asphalt shingles, blow their protective granules off, and void any warranties. 

This is a huge mistake that even some roofing companies make. The only way to avoid causing damage is to spray off the solution with low-pressure water or by soft washing. 

However, even this has to be done right. So, do more research about water pressures before diving into moss removal. 

Should you clean moss off a roof yourself?

As a roofer, I recommend hiring a professional. If you don’t have experience walking on a roof or being on a ladder, you shouldn’t risk your safety to clean moss off your roof. 

The fact that the roof will be wet makes it even more dangerous. You could also end up damaging your roof more, leading to costly problems and potentially voiding your warranties

However, I recommend hiring a roof cleaning company specializing in moss and other vegetation removal instead of a regular roofing company. This isn’t to say roofing companies can’t do it, but you just want to ensure it’s done right without causing unnecessary damage.

Can you prevent moss from growing on your roof?

While not guaranteed to fully stop moss growth, there are ways to be proactive against it. The easiest way is to get regular roof maintenance to clear debris.

debris sitting on an asphalt shingle roof

Sitting debris can become saturated, creating the perfect moss growth environment if left untouched. On top of maintenance, trimming overhanging tree limbs back and keeping your gutters clean will help prevent excess moisture buildup.

Another effective way is to install copper or zinc strips along your roof ridge. As rain goes over the ridge, small amounts of metal ions from the strips flow down with the water to act as a natural deterrent. 

This will be costly, but it’s a solid option for roofs that sit in the shade most of the day. 

Does moss on your roof mean you need a roof replacement?

Moss is a sign that it’s time for a new roof, but it doesn’t necessarily mean you need a replacement as soon as it starts growing. It could be growing from debris buildup, lack of sun hitting a damp roof, overhanging trees, etc.

But while it may not need replacing right away, it’s time to start thinking about a new roof. You can remove it to buy some time, but moss sitting on your roof damages the asphalt shingles. 

If it was able to sit for a long time, there’s no telling the damage waiting underneath. At the end of the day, you won’t know if you’ll need a new roof until after an inspection by a roofing contractor

However, an older roof with moss means you need to start budgeting for a new roof before leaks show up. 

What are other signs that you need a new roof?

After reading this article, you know how to remove moss from your roof, what to use, if you should do it yourself, and how to prevent it. I recommend hiring a professional for any roof cleaning project, but it’s completely up to you. 

Just remember that moss is a sign that it may be time for a new roof, so cleaning may be pointless. However, you can’t make a decision based on moss growth alone. 

Moss and other vegetation is just one sign, but there are others to be on the lookout for. That’s why I wrote another article with all the signs it’s time for a replacement. 

Check out 6 Signs Your Roof Needs to be Replaced to help determine if you need a new roof before contacting a roofing contractor.

roofing contractor questions checklist

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