Does your roof look far too green for your liking? Use the following methods, tools, and materials to eradicate moss from your roof.
The only greenery you should be able to see near your rooftop is the leaves growing off branches from surrounding trees. If you have moss growing on your roof, then it’s time to do something about it.
If you have moss growing on your roof, there’s a high chance you have a north facing roof. A north facing roof usually has little sunlight, which enables moss to buildup on the roof. Moss can grow quite quickly, and it will grow in between roof tiles, filling in the voids and lifting up roof tiles and slates.
Moss growing under roof slate and tiles can push the slate out of position allowing rainwater to seep into the roof structure. When rain finds its way into the roofing structure that’s when decay and rot sets in.
If you want to clean moss off a roof yourself, you will have to plan how you are going to kill the moss and remove it effectively. You will need to treat the roof to stop the moss from growing back.
Its recommended anyone cleaning moss off a roof should do it on a cloudy day. When applying roof cleaning products onto a roof on a hot sunny day, it will quickly evaporate, and you won’t get the desired result.
Most roof cleaning products require at least 20 minutes for it to absorb into the moss. However, there is more than one way to remove moss from your roof tiles.
Moss can also be removed by using a stiff brush and some water to aid it. You can also attach a soft bristle brush to a long extendable pole if you have one so you can reach a lot further. You could even combine using a stiff brush on an extendable pole and using environmentally safe chemicals to kill the moss.
It’s important to note if you use any chemical on the roof to kill the moss make sure it's environmentally safe. If it’s not safe for the environment, it can find its way into flowerbeds and lawns below and kill everything in it.
When applying moss killer onto roof tiles be sure to protect any nearby plants. Plastic sheeting is the best way to protect your garden from any chemical overspill. It would also be a good idea to hose down any small trees, plants, and shrubs with water. The water sprayed onto these will dilute any chemicals that might spill down and land on them.
I always recommend using Smartseal Moss Remover because its the most effective at killing roof moss.
Roof Moss Treatments
Some roof moss killer products like Smartseal Moss Remover can be applied to the moss-covered roof tiles without having to rinse it afterward. It’s always important to read the manufacturers instructions because not all roof moss killer products work the same.
Other products such as Wet & Forget are available to buy to put in spray bottles that attach to your hose. Make sure you read the instructions carefully to get the right balance of chemicals and water together before spraying on your roof tiles. The last thing you want is a chemical reaction on your roof tiles because the concentration of the moss killing chemical is too high.
It’s also possible to make homemade moss killer for roofs if you like to experiment and save some money. Homemade moss killers are generally less toxic than the ready-made chemical products you buy from the shop.
You can use chlorine bleach to remove fungi, mildew, and moss. You have to make sure that it is diluted before spraying the mixture onto the roof or it may damage any nearby plants and shrubs.
A good rule of thumb is to add one-quarter bleach to 1 gallon of water. Add a quarter cup of heavy duty cleaner such as trisodium phosphate. A word of caution – be sure not to use any ammonia-based cleaning products because when the extra bleach they create toxic fumes.
Alternatively, you could make a solution which is friendlier to plants by adding 1 cup of oxygen bleach to 1 gallon of water. Another cheap home remedy is to mix 3 ½ cups of white distilled vinegar to 2 gallons of water. Pour the vinegar & water solution into a garden sprayer and spray into the problem area.
If you plan on going up the ladder to spray the roof, then it will be much safer to use a backpack sprayer which will leave your hands free to hold the ladder while you’re on it.
When you have decided on which roof moss removal solution you would like to use, it’s time to put what you’ve learned into practice. Below is a step-by-step guide showing you how to remove moss from your roof tiles.
How to Clean Moss from the Roof
Here’s what you will need to clean moss from the roof yourself.
- A long soft bristle brush
- a ladder
- rubber gloves
- protective goggles or safety glasses
- a safety rope
- your chosen roof moss killer/cleaner
- a scrubbing brush
- a garden hose with an attachment for a spray nozzle
- old work clothes, non-slip footwear, and a hat to protect your hair
- a backpack sprayer or garden pump sprayer
- power washer (optional seat notes)
- Make sure you have dressed appropriately for the job. It doesn’t matter which cleaning solution you choose you will get dirt on your clothes. It is essential that you have on your safety glasses, rubber gloves, old clothes, and nonslip footwear. If you are going up ladders onto the roof, it is essential you have a safety rope or harness with you.
- Be sure that you cover any nearby flowerbeds and plants with plastic sheeting. Position your ladder in place. Pick up the garden hose and slowly make your way up the ladder.
- Spray the moss covered roof with the water from the hose. It’s important to make sure you work from the top of the roof downwards. The water will run down the roof tiles naturally, just like rainwater would.
- The next step is to take hold of your soft bristle brush and brush away as much of the moss from the tiles as you can. Try to imagine a square roughly the size of 1-meter x 1 meter and work in that part on the roof until it is clear of moss. By working one small section at a time, it will give you better control of the brush, and you will conserve energy.
- Once the area is as clean as you can get it with the soft bristle brush, it is now time to spray the roof with your chosen moss killing solution. Use a large spray bottle or the backpack sprayer to spray the roof with the moss remover cleaner. If you used a homemade solution, be sure to let it soak for at least 20 minutes before rinsing.
- Pick up the hose again and slowly work your way up the ladder. Point the hose towards the top of the roof and rinse off the moss killing solution along with the dead moss. Take hold of the soft bristle brush and scrub away any remaining moss. Rinse the roof again with the hose to remove any remaining loose moss sitting on the roof.
- You also have the option of using a power wash to blast away the moss, but it’s not without its own set of problems. Before you even consider using a power wash on your roof, it is vital to inspect the roof tiles and make sure none are missing or broken. If high-pressure water is aimed near any damaged or missing roof tiles, you will end up causing more damage than the moss ever did. If you are to use a power washer you have to make sure you are standing on top of the roof and pointing the power washer downwards. If you do decide to use a power washer to clean the moss off your roof make sure the pressure washer is set on the lowest pressure setting to avoid damaging your roof. Using a power washer on a roof is a personal choice however you can read my guide called should I use a power washer on my roof to learn about any potential problems caused by using a power washer to clean a roof.
Prevent Moss from Returning
Once you have removed the moss from your roof the next step is to think about preventative measures how to keep moss from growing back on your roof. One of the best things you can do to prevent moss from re-growing on your roof is to allow sunlight on it if possible. If your home has trees around it with long branches blocking the sunlight from your roof, it would be a good idea to trim them down. Be sure to keep your gutters clean by removing any moisture collectors such as mud, leaves, and twigs. Remember moss loves moisture and absorbs it like a sponge. If the gutters are full of debris, it will pile up and will encourage moss to grow back on the roof.
Is there a long-term solution to stop moss growing back on the roof?
Fix a length of copper (or zinc) wire all the way across the top of your ridge tiles. When it rains, the rainwater hits the copper wire and leeches out moss killing particles which run down your roof tiles and kills off any moss trying to regrow.
By following the instructions of this roof moss removal guide carefully, you will ensure you won’t have to get the ladders and spray bottle out again for a long time (possibly years.) It will look like you have a new roof again.
If cleaning moss off your roof seems like a daunting task, you can always get a FREE NO OBLIGATION quote for roof cleaning. Simply pop your details into the form below and let the professionals take care of it while you relax!
You'll have a sparkling roof in no time!
Jim Ardale (Roof Advisor)