How To Deal With Moss On Roofing Shingles

If you have moss on your roof shingles, be thankful and do not panic. The moss is one of nature’s plants and a natural part of our environment. Moss can grow back if removed in the right way. However, green moss on roof shingles is not a natural occurrence but an unwanted image. The green moss is caused by the growth of algae that has found its way onto your roof through rainwater and leaks from the gutters or board siding around your home’s exterior (you can avoid this by installing gutter guards). You may have to do some “gardening” to eliminate it without damaging your home or making it look worse than before you started the process. If you attempt to remove the green moss yourself, make sure that you take the following steps:

Major Causes of Moss Growth on Roofing Shingles

Replacing Your Roof Decks or Shingles

The first and most apparent cause of moss growth on roofing shingles is simply having an old roof deck or shingles in place. If your roof has been installed for several years, most likely, it will be dirty, dry, and mossy. Without the proper maintenance, this will promote moss growth quickly.

If your home’s roof is still in good shape but requires a fresh coat of paint or a new deck or shingle layer to take care of the problem, it is crucial that you not go out and replace them both at the same time. While your roof’s foundation is being worked on, the moss will get cleaned off. However, it will quickly return when the new shingles or deck are installed, and the water is allowed to pool again, providing less need for regular cleaning.

A Lack of Good Drainage

Another common cause of moss growth on roofing shingles is poor drainage of the rainwater that hits your roof. When water is allowed to pool on your roof, it will inevitably start building up algae and moss from the spores in the air or on the ground nearby.

To prevent this, you must ensure that the gutters are in good repair and not blocked by leaves or other debris. Otherwise, water will not drain off your roof freely. If your gutters are blocked, you can fix this by cleaning out the debris and other obstructions, which will unblock them.

If a constant flow of water comes off your roof, draining it into your gutters as they should be, then you will want to clean off the moss that has already begun growing on your roofing shingles. That can be done by washing them with a solution of soap and water or scrubbing them with a commercial detergent-powered cleaner and a stiff brush.


Your roof placed on your home can affect how much moss grows on your roof. If you have a roof closer to the ground than others, it will naturally collect more dirt and debris when it rains, promoting moss growth.

How to deal with moss on roofing shingles

Using bitumen membranes

Bitumen membranes are always an essential part of a roofing system, as they are waterproofing and weatherproofing. Roof membranes are made of synthetic materials based on either polymer-modified or unmodified bitumen. They can be found in 2, 3or 4 inches thick and come with either a one- or two-sided application. Bitumen membranes are impervious to water, wind-driven rain, insects, and other outdoor elements such as corrosion caused by freezing/thawing cycles. The best quality bitumen membrane is flexible yet tough enough to stand up to high winds without tearing away from the roof deck beneath it. Surprisingly, bitumen membranes last longer than any other roofing material, including shingles.

The primary purpose of a bitumen membrane is the prevention of water infiltration into the building, which is especially helpful for commercial buildings. If a roof membrane is appropriately installed, waterproofing will not be an issue for many years, preventing leaks from causing significant damage to ceilings, walls, and furniture within a structure and expensive repairs or replacements.

Apply Sandpaper

If your roof shingles are made from cedar, applying some sandpaper can help remove green moss from them. If your shingles are made from some other kind of wood, or if they are asphalt, you will need to use special sandpaper that can be purchased in a hardware store. After sanding the moss off, take some more time to clean up the debris and remove any bits of moss that might still be on the shingles. Remember to wear protective gloves to avoid damaging your roof.

 Apply Vinegar

If possible, try to water down the vinegar before applying it. That can help to make it easier for you to spread a thin layer over your entire roof and into every nook and cranny between the shingles. Keep in mind that you want to ensure the vinegar is completely dry before it can adhere to the shingles because if there is moisture at all, this might cause some issues later on. Wait a couple of days and then go back over the area with a rag and try to wipe away as much of the green moss as possible.

Spread Salt

Many people have successfully spread table salt over their roofs to kill off green moss. Do not do it if it is going to rain or otherwise wet because it will not work nearly as well in this scenario. After you have spread all the salt, leave it on overnight, preferably with a fan blowing on it to dry and finish off any remaining moisture. Remember that there are many different salt brands, so test them out in your area to see which ones work best.

Use a Moss Killer

Using a moss killer is a simple way to remove moss on your roof permanently. Of course, you do not want to use this method unless you are certain that the roof will be susceptible to continued growth if you only use water. If the solution penetrates through your shingles and treatment is not thorough enough, new moss can grow from places where the chemical previously killed it. You should always use caution when using chemicals around your home because many of them are toxic and can cause serious bodily harm if misused.

Using an Electric Fan

If you are interested in keeping green roof moss from returning, you might want to try using an electric fan to help speed up the process. The air is a bit of a vacuum, and if you can get your hair dryer pointed right at all of the moss, this might help. You will want to start by blocking off your bedroom windows so that you can try this method first and see how it works for you before proceeding any further. Give your electric fan about 5 minutes to get things started, then turn it off until it’s all finished.

Moss can be highly problematic for many reasons. For starters, moss can make the roofing shingle appealing during the early stages of growth. However, it is imperative to remove moss as soon as it appears. It prevents heat from escaping through your home’s roof and onto its ceilings, making your house more susceptible to mold and mildew. Moss also exacerbates ice damming on roofs and creates an environment in which it is challenging for insulation to do its job correctly.