- 1. Where Moss Comes From
- 2. How Damaging is Moss for Your Roof
- 3. Moss Removal Solutions
- 4. Preventing Moss Growth on the Roof
Some people find the look of moss on a roof quite charming. It’s understandable considering the lush green appearance that gives the house an old-world cottage vibe. Unfortunately, moss can cause decay to the roof so it’s best to clean that green upholstery using some high-performance methods. In this article, we’ll explore the most effective ways to get rid of that mossy foliage for maintaining the health of the roof.
1. Where Moss Comes From
Moss can start as fairly inconspicuous clumps of greenery in shaded areas of the roof. It’s not immediately noticeable but it’s able to take over the roof surprisingly fast when left unchecked. Although moss, lichen, and algae tend to prefer moist areas that are out of direct sunlight, you can easily have considerable growth even in less-than-ideal conditions. It’s not unheard of for homeowners living in fairly dry areas to face a moss problem on their roofs.
Moss can spread easily through spores transported by wind or bugs. Once the conditions for blooming seem right, the greenery starts to develop. In most cases, moss starts to grow on the side of your roof that faces North. A roof sunlight deficiency appears to be a very favorable condition for mossy foliage.
One of the most difficult aspects to deal with when it comes to moss growth is the way the greenery is distributed. Moss starts as a thin layer on the shingles but it becomes gradually thicker over time. It will eventually seep in the seams between the shingles where it grows more easily thanks to better-shaded conditions. Once the moss develops further, you can face extensive damage to the roof.
2. How Damaging is Moss For Your Roof
Moss can pose a serious danger to the health of your roof’s elements. Assessing the damage potential of mossy growth depends on the type of material used for your roof’s construction. Whereas sturdier materials such as asphalt, slate, and fiberglass come with some chemical protection against moss or algae growth, the same can’t be said about traditional old shingle roofs.
Mossy growth can hide in deep crevices in the shingles and its thickening will make raise the shingles. This process can easily ruin a roof made of wood because it features a porous surface that’s more susceptible to the effect of mossy growth. If the moss gets firmly established in the wood shingles, it’s safe to say that it will be extremely hard to remove compared to other materials like asphalt or composite.
The most damaging effect of moss involves its ability to retain moisture. That may not seem a huge problem in the initial stages of development but thick mats of moss can easily encourage root and decay of the shingles. All that accumulated water will slowly infiltrate through the structural elements of the roof causing a lot of damage.
Some roof materials such as metal should offer better resistance to issues caused by moss and fungus growth. However, the increased dampness of moss that’s left out of control can eat through the protective layer of a metal roof. Then you will notice that rust or corrosion problems start appearing. Even if you get rid of the damaging moss patches on the metal surface, you will most likely have to repaint the entire roof.
3. Moss Removal Solutions
Now that you understand the potential danger of leaving that mossy growth to develop further on the roof, it’s time to explore some reliable removal solutions. Regardless of the method or product chosen, make sure you act as fast as possible to minimize the damage created by moisture buildup. It’s not just the shingles that can be affected but you can also face gutter blockages or other structural weaknesses.
3.1 Use a Stiff Brush
The easiest way to get rid of clearly visible mossy growth on the roof is to use a stiff brush and apply some elbow grease. It’s an inexpensive moss removal solution that’s not particularly difficult as long as you can get access to the roof. Choose a dry day for the best results.
Consider getting a professional-grade scrub brush with stiff bristles as the Unger HydroPower found on Amazon. Combine it with a long handle from the same manufacturer to extend your reach while cleaning the roof.
Keep in mind that scrubbing the roof needs to be done carefully to avoid damaging the roof. Work slowly and try a gentler brush if the roof material can be easily scratched. Don’t lift the shingles during cleaning.
While manual work with a brush is a decent short-term solution, you will also need to incorporate more advanced moss-killing methods to fully get rid of the spores. Scrubbing with a brush is enough to clear the roof from the visible growth but moss can regrow from small leftover bits or hidden spores that are much harder to destroy.
3.2 Apply a Moss Killer
There are various products on the market that can be effective against moss growth and its spores. You can usually take your pick between liquid chemicals or dry powders. Moss can be killed with minimal effort with DIY vinegar or bleach solutions but these aren’t recommended because of the risk of accidentally landing in other areas. They should be avoided to protect plants in the garden that can be affected after rinsing the solution.
3.3 How to Remove Moss With a Dry Powder
A fairly effective removal method involves the use of specially formulated dry powder designed for moss treatment on the roof. Powders are usually based on zinc sulfate monohydrate that has lots of uses, including the elimination of moss spores. Check out this dry formula from Lilly Miller Moss Out, available on Amazon. Its granular texture can be sprinkled more effectively on the affected roof.
The powder acts as a strong moss deterrent and killer but it can be a bit challenging to apply correctly. You will need to be able to reach the roof properly because this is the kind of moss killer intended for hands-on application. The good news is that once you gain access to the roof, you will have a clearer picture of the moss problem and can remove the spores more effectively.
Try to disperse the killing powder as evenly as possible on the entire roof area affected by moss growth. Don’t worry too much about the white streaks left behind. They will be washed away eventually after a couple of heavy rains. That’s actually a key element that enables the full killing power of the dry powder because adding water to the mix will help to distribute the powder properly and clear the surface from the pesky mossy foliage.
While the dry powder method is fairly effective in terms of moss removal, it comes with some disadvantages. Aside from requiring you to climb to the level of the roof, the powder can sometimes not work as expected, depending on the environmental conditions. Strong winds, in particular, can potentially blow it off before it gets the chance to mix with water and kill the moss spores.
3.4 How to Remove Moss With a Liquid Product
A more popular option for controlling moss growth on the roof or other areas of the house is to use a liquid product. This type of moss killer is usually available in a more convenient spray form that can cover the surface of the roof in a fairly uniform manner. It’s recommended to climb on the ladder to get an adequate reach but the product can be applied from the ground if you have the right equipment.
Consider getting a special moss killer that uses a bleach-free formula and can reach long distances with ease. One solid example is the Wet & Forget outdoor cleaner that’s designed to eliminate moss and other growths that love moisture such as mold and algae. With a single bottle, you can destroy mold spores safely for an area up to 2,000 sq. ft. Intense scrubbing isn’t required as rainy conditions will assist to fully eliminate the moss spores.
Even if you use a gentle liquid chemical product, it’s still important to be mindful of any runoff landing on delicate plants in the garden. A solution to this problem is to ensure those plants are wet before rinsing the roof. Plastic sheeting can also be used in some areas to keep exposure to a minimum. Similar to the dry powder method, it’s recommended to avoid applying the liquid moss killer on a wet roof and wait until it’s properly dry.
3.5 Power-Washing the Roof
Both the dry powder or the liquid moss killers can achieve excellent results when used as instructed. While it may be tempting to cut some corners and try pressure washing the roof, it’s important to keep in mind some considerable downsides to this method. It’s generally a bad idea to make use of a power washer for moss removal.
The excessive force from pressure washing can cause more problems for the roof’s structural integrity. That’s especially the case if you already have chipped or broken shingles on the roof. You can actually make things worse through power-washing because more water will be directed through the cracks. There’s also the risk of removing the protective coating that’s already in place on your roof.
If you still consider pressure washing the roof against the moss, you can at least ensure that only the lowest power setting is used. To obtain any decent results, you will also need to somehow position yourself above the moss to avoid pointing the washer upward and damaging the shingles. This can make the whole process more dangerous because you have to stand on the roof.
4. Preventing Moss Growth on the Roof
Now that your roof is free of damaging moss, you should consider taking some additional measures to prevent this kind of problem from resurfacing. The following prevention methods are recommended so you can reduce the maintenance work required when it comes to moss removal from the roof.
4.1 Let the Sunshine in
Shaded areas are the perfect breeding spots for moss so it’s not surprising to find out that sunshine represents a great natural deterrent. Preventing shade isn’t always easy or convenient for many homeowners. One solution you can try is to trim the surrounding trees so that more sunlight can find its way to your roofing system. Move garden features that bring shade to the roof in another spot if possible.
4.2 Keep the Roof Clean
Spores can develop more effectively in a roof full of leaves, sticks, and other debris. Maintaining the roof clean can often be a strong measure on its own to prevent any moss problem. It’s also important to ensure that your gutters stay clear of organic materials as well. Without adequate drainage, the roof is exposed to increased moisture that encourages mossy foliage growth. This is particularly important for some types of roofs such as those that use wooden shingles.
4.3 Install Zinc and Copper Strips
This is a smart idea for the effective long-term prevention of moss on the roof. Place zinc or copper strips under the ridge or peak of the roof. They will oxidize over time so that metal particles are carried down the roof with the rain. This results in a poisonous barrier for the moss. It’s not strong enough to kill already established thick moss growths but the metal strips will make the area very inhospitable for new moss formation.
Check out this zinc strip roll made in the USA as well as this general-use copper flashing that can be found on Amazon. Copper is usually more expensive but it’s slightly more effective against moss compared to zinc. Installing these metal strips will usually require the services of a contractor but they also support DIY mounting. To get the best benefits of zinc or copper strips, it’s recommended to have them installed on a brand new roof. In that case, the chances of moss or algae growth will be severely reduced.