Moss must have a damp environment, which is why it is so often found in wet areas, such as swamps, and in forests where moisture is held for longer. There are many species of moss, and all of them are lovely – but not when they begin to grow on your roof!

When you see moss on the roof, you must get rid of it immediately. The instructions on how to remove moss on roof is pretty straightforward: First you kill the plant, then you carefully remove it, and then you take steps to prevent it in the future. Here’s how to make all three of those things happen. 

Understand Why You Need to Remove Moss from Your Roof

When moss begins to grow on the roof, it can cause serious problems. As the moss grows and thickens, it begins to creep underneath the shingles, lifting them up the slightest bit. Once that happens, water can get underneath your shingles when it rains, or high winds can pick the shingles up and pull them off. Either way, it allows water to get in, and that leads to eventual rot of the wood underneath the shingles. Pretty soon, you have a roof leak that can be expensive to fix.

But moss does even more than this. Moss on roof can catch various types of debris and insects, which can also lead to water problems. And besides that, the moss can damage the shingles themselves by breaking them down. 

How to Kill Moss on Roof

Moss can be lovely, but once it decides to invade your roof, you must be ruthless and kill it immediately. There are a few ways to do this.
1

Brush it away

A long-handled brush can make easy work of a simple moss problem. Use the brush to dislodge the moss and knock it down. Don’t use the brush too forcefully, because you don’t want to damage the roof. Once you have done this, use specialty moss remover soap, taking care to use it exactly as directed on the package. 

2

Try Moss Out Liquid Concentrate

This concentrate works very quickly to kill moss, not only on the roof, but on other areas as well, such as the deck or your siding. Made of ammoniated soap of fatty acids, this concentrate application can work for up to one year. Once the moss is dead, use a long-handled brush to remove it from the shingles. 

3

Spray with salt and hot water

For those who want a more natural approach, simple sea salt and very hot water can be sprayed onto the moss. Use a household pump spray bottle to apply it, let it soak for twenty minutes, then scrub away the moss. You might have to repeat this several times to get the roof completely clean. 

4

Use a zinc strip

This is one of the easiest ways to get rid of the moss. Simply attach a strip of zinc to the top of the roof. As rainwater runs over the zinc strip, it creates an alkaline condition on the roof, and this kills the moss very quickly. If you don’t want to add the strip to your roof, you can use products that include zinc sulphate. These are available in both granular and liquid form. 

5

Zinc chloride

Just like zinc sulphate, this works well to kill the moss immediately. Zinc chloride can be used safely on larger areas without causing any problems for animals or vegetation that you want to keep. This often works well for large areas where moss has been an ongoing problem. 

6

Commercial weed killer

It might sound strange to put something meant for your yard on your roof, but you’re trying to kill a plant – and that’s exactly what these weed killers do. Look for one that is environmentally friendly, because it will be carried off with rainwater, and you don’t want to put toxic weed killer on your house anyway. 

7

Preservatives

A good preservative solution on your roof can prevent the buildup of moss and almost anything else, for that matter. Look for a preservative that is specifically meant for roofs, and keep in mind that it will likely need to be applied every five years to have the maximum protection. 

8

Bleach

Look for products that contain bleach, and use them according to the manufacturer’s directions. These are not corrosive to metals, so they can be used on a roof where part of the structure is made of metal. Just remember that some of these solutions might discolor painted areas. You might have to use the bleach solution once a year to maintain results. 

Warning: There are some things you should never try when it come to moss removal. Avoid pressure-washing, as this can force water under your shingles and lead to even worse problems. Never use an acidic mixture, as it can eat away at the shingles. Don’t scrape at the moss, and when you apply any mixture or water, do it from the top down to avoid damage to the shingles.  

How to Remove Moss on Roof

Killing the moss is great, but what about removing it? You must remove it, as even when the moss is dead, it can still retain water. Moss can also grow back very easily, which means that even dead moss can be a great breeding ground for new moss.
1

Let nature take its course

In some climates, the moss will dry up very quickly and be blown away by high winds. This is a situation that might or might not happen, though, so you must pay close attention to the roof during this time. Some cleaners will claim to help the moss loosen from the roof, so you can simply put these on and then wait to see what happens. Keep in mind that if the moss doesn’t go away, you will have to work on it with some other method to make sure it does. 

2

Brush and wash

This method means that you get up on the roof with a long-handled brush and water, or whatever cleaning solution you are using, and put some elbow grease into removing the moss. Soak the area of moss about a week before you plan to do this, to help kill it and loosen it up a bit. Then simply wet down the area and brush it with circular motions. Always do this when the roof is wet, or you risk damaging the shingles. 

3

Pressure washing

This method is not typically recommended, as it can cause serious problems with your shingles; however, if you do choose to try this, make certain that you are using the washer on the lowest setting and that it is aiming downward across the shingles, never upward or even to the side. Before using this method, use a heavy-duty cleanser that will kill the moss quickly and thoroughly. 

How to Prevent Moss on Roof

Now that it is clear how to remove moss on roof, the important question becomes: How can I avoid moss on the roof in the first place? Fortunately, there are many ways to do this.
1

Zinc strips

Begin by installing zinc flashing on the top of your roof. These strips can create an environment that moss simply can’t grow in, and thus that means they will not invade your roof. 

2

Avoid overhanging tree branches

To make doubly sure it doesn’t happen, make sure there are no tree branches that overhang your house. The moisture from the trees can make your roof more hospitable to mold, mildew and moss, none of which are things you want! 

3

Nip it in the bud

If you see any moss in the surrounding area, get rid of it immediately. Mold spores can travel a great distance to settle on your roof. To that end, also keep your gutters as clean as possible, especially during the fall months when the leaves begin to clog them up. 

4

Switch shingles

Apply a preventative treatment to your roof, or a sealant that will help ensure moss doesn’t grow. When it is time for a new roof, make sure to get the kind of shingles that are resistant to moss and any other type of problem that might grow on them. If you’re not sure about what shingles to use, speak to a qualified roofer who can tell you what the options are. 

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  • Anna PicketFeb.12 02:05
    That's scary that mold spores can spread so easily. I can see why it would be important to act fast if we saw any moss on the roof to prevent anything like that from spreading. Maybe next time we get our roof repaired, we will switch to shingles that won't let moss grow on them.
  • Daelin Jun.17 17:05
    It's pretty fascinating that a zinc strip can so easily avoid moth growth. As you said, moss can cause very serious problems for the roof and the structure underneath. Water damage can greatly weaken the integrity of the wood. When we lived in Washington we had to keep a careful eye on our roofs because of the extra moist environment. Any sign of mold or moss required immediate attention.
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