I guess the first question is: Is it really all that bad to have moss on your roof?  And a quick follow up of: Why?Well the short answer is Yes, it is bad to have moss on your roof. Moss will shorten the life of your roof and cause the roof to rot.  The moss can lift up shingles and constant moisture can lead to bacteria and mold growth. This eventually can lead to holes in your roof and leaks into your home. It is also dangerous to walk on a moss covered roof because it makes surfaces very slippery when wet.Moss is a plant species that grows really well in moist cool areas. There are many different species of moss. Some common characteristics among these species are that moss does not have flowers or seeds, they must have a damp environment to grow in because they do not have any root system to secure water, and they are usually extremely green with tiny leafs.Moss likes:
  1. A shady climate. The climate doesn’t need to be too shady but shade is optimal.
  2. Acidic environments. More specifically moss grows optimally at a pH level of 5.0 to 5.5.
  3. Moss grows well on hard surfaces.
  4. Moss needs a moist/humid environment to grow.
Some good prevention methods are:
How to remove moss from the roof?Wondering how to remove moss from your roof? This page has been created to share the various ways to remove moss on shingle roofs. Not only does this page share the methods to remove moss but it also helps you understand the problems that arise from a mossy roof, how to prevent a mossy roof, and overall gives you a better understanding in order to properly deal with moss on rooftops.*Please refer to the table of contents to skip to any section of this page you are most interested in.*We also just published an article on how to clean vinyl siding if that interests you as well.New Article: Do Gutter Guards Work?
Available Roof Cleaners Online
You can order high quality roof cleaners online that actually work. What are some of the most popular and effective roof cleaners on the market? (These are DIY roof cleaning products for consumers primarily)Spray & ForgetSpray & Forget is a DIY cleaning product that is used for cleaning moss, mold, and mildew off roofs and other surfaces. The product was invented by Scott Dudjak who is the current owner of the company. Their company is located in Sugar Land, Texas.spray-and-forget-roof-cleanerProduct Reviews“I originally wrote a bad review for the product, but I’m now amending my comments and rating. I tried everything to clear the green algae from my roof, but nothing worked until I applied this product late last summer / early fall. My roof cleared up in the spring and early summer this year. I’m happy to say that it’s now clean! I’ll be spraying the other side of the roof this weekend where I hadn’t sprayed before to see if it will clear the black looking algae stain on the other side of the roof.” ~ Lisa S.– Read More Reviews HereWet & ForgetWet & Forget is another roof cleaner that can be purchased online and applied by the consumer. This product is for cleaning moss, mold, and mildew.wet-and-forgetProduct Reviews“I only ordered a half gallon of this product because I was skeptical that it would work as advertised. After applying it according to the directions I am now convinced that it actually does what it claims – i.e. removes moss, mold, mildew and stains from outdoor surfaces.I have a wooden deck and stairs on my house that I applied this product to about a month ago. Just as they claim, each time it rains the product reactivates and goes to work. All of the green crud has disappeared. It does work better on horizontal surfaces than vertical as the instructions suggest but even on vertical surfaces where the rain does not reach the moss has almost vanished.I plan to observe how it does for about 6 months and then reapply it if needed, although they claim that it will continue to work for up to a year. So far so good – it appears to be a good product.” ~ J. Ferris Roof WashRoof Wash is specifically designed for cleaning roofs. The product was made with the help of a professional roof cleaner who had been in the industry for years. The product is mixed with water and then spray onto the roof.Roof WashProduct Reviews“I asked numerous people if it was possible to clean my roof and no one seemed to know. So I searched the internet and found this product. I had 2 unsightly areas on my roof covered with mildew and moss. I used this product as directed and gently brushed off the growth. The areas now look like new. I plan to clean my entire roof this spring. I also like that this product contains hydrogen peroxide and can be safely rinsed down the gutters.” ~ Steven P. 
What is Moss?
How to remove moss on roofsMoss is a plant species that grows really well in moist cool areas. There are many different species of moss. Some common characteristics among these species are that moss does not have flowers or seeds, they must have a damp environment to grow in because they do not have any root system to secure water, and they are usually extremely green with tiny leafs.
What Promotes Moss Growth?
  1. A shady climate. The climate doesn’t need to be too shady but shade is optimal.
  2. Acidic environments. More specifically moss grows optimally at a pH level of 5.0 to 5.5.
  3. Moss grows well on hard surfaces.
  4. Moss needs a moist/humid environment to grow.
How to Kill Moss?
  1. Take away the shade that the moss is growing in.
  2. Turn its environment extremely acidic or turn it into a base environment (above 7 pH levels).
  3. Take away the moisture or water from the moss.
About Method #1 & Method #3#1 & #3 can be a little tricky to do for people whose roofs are in a naturally shaded/humid environment. Some options would be to remove trees around the home in order allow extra sunlight in. This could be a fairly expensive solution but would be a solution that would last for years to come.Roof Cleaner SprayFor those people who have moss or algae growing on their roofs and do not want to remove their trees around their home the solution that would work best for them would be #2. This is most commonly done with roofing cleaning products. (We have shared 3 with you above & included links to reviews left by unhappy and happy customers.)
 
Remove The ShadeBecause moss grows well in shaded areas one way to control moss/remove it from roofs or other areas is to remove its shade. This can be done by removing trees, trimming tree branches to allow more sun to penetrate, or remove bushes and other type of plant life that may be blocking the sun.This method of moss prevention and removal is highly effective but remember that it may be ineffective if the weather is often overcast and cloudy.Make its Environment Acidic (below pH 4)There are many common household items that have a pH level at or below 4. These products are highly effective at killing moss. Using these products with a mixture of water or directly to the moss can kill the plant. Be aware that acid products erode certain types of surfaces. By diluting the mixture you can prevent unwanted corrosion.
  1. White Distilled Vinegar (Apple Cider Vinegar As Well)
  2. Orange Juice
  3. Lemon Juice
  4. Tomato Juice
Make its Environment a Base (Above pH 7)Since moss grows in a pH environment of 5.0 – 5.5 or 6.0, by changing the environment to a base level it will effectively kill the moss. Below is a list of some common household items that are bases. By mixing these products with water or by applying them directly they can kill moss in yards, off of roofs, siding, decks, or other unwanted areas.
  1. Baking Soda
  2. Baking Powder
  3. Salt
  4. Ammonia
  5. Soap
  6. Bleach (Do not mix bleach and ammonia)
Warning: How Not To Kill Moss on Roofs
damage-to-roofs-casued-by-roof-cleaningRoofs are an investment that must be safe guarded. That being said, we want to give you some “what not to do” tips when trying to remove moss off of your roof.1. Do not pressure wash the moss offBy using a pressure washer to remove the moss you are going to dramatically reduce the life of your roof. How? The high powered water will remove the asphalt shingle granules which help protect the shingles and ensure a longer life span.2. Be careful with using acids to remove moss. If your acidic mixture is too strong or stays on the roof too long, it can eat away at the shingles. If your roof cleaning solution has not been tested previously, make sure you test it on some spare shingles before applying it to your roof.
3. Do not scrape the moss off of the roof. This can rip, crack, and break the asphalt shingles themselves.
4. If any water is used to remove the moss, do not spray the water at an upward angle. If you do, this can cause water to go under the shingles and leak into the house or rot the wood decking of the roof.
Why is Moss on The Roof Bad?
Although the reasons are some what debated in the roof cleaning industry there is definitely one common conclusion and it is that moss is not good for roofs. We have posted a few of the reasons commonly accepted within the industry for why moss is bad for shingle asphalt roofs.
  1. As the moss thickens and grows on an asphalt shingle roof it can raise the shingles up (much like a jack under a car). When the shingles get risen it allows water to go under the shingles causing the decking to rot and causing the roof to leak. The raised shingles also pose problems when heavy winds are present because they will catch the wind like a sail and this can cause shingles to be torn/blown off the roof.
  2. A moss buildup on the roof causes more debris to get trapped on the roof. This debris promotes water buildup which makes the roof at risk of much more rotting and leaking.
  3. Moss can actually damage the asphalt shingle components leaving it to break down faster.
Roof Cleaning Recipe Solutions
We make no claims or promises regarding these homemade cleaning solutions. Please be sure to test the solutions on a shingle that is not located on your roof before applying the moss killer soltution to your entire roof.
Dish Soap Recipe4 ounces of Ultra Dawn Dish Soap
1 Gallon off WaterChlorine Bleach Moss Killer Recipe5% – 10% Chlorine Bleach
90% – 95% WaterVinegar Moss Killer Recipe5% – 10% White Distilled Vinegar or Apple Sider Vinegar (100% Vinegar Solution)
90% – 95% WaterOther ingredients that you can experiment with are:
  1. Salt
  2. Baking Soda
  3. Baking Powder
  4. Ammonia
  5. Lemon Juice
  6. Sodium Hydroxide