One thing composite decking makers boast of is the beauty that composite decking will add to your backyard or wherever you install it. But one thing about composite decking’s beauty is that it can quickly be distorted when you don’t maintain your patio. Algae, moss, mould and mildew can quickly develop on your plastic wood decking. Let’s use green algae as an example. Algae can create an unpleasant situation when it grows on your composite decking. This write-up explains how to remove algae from your composite decking surface.

Composite Decking Maintenance

The key to making your composite decking stay beautiful is cleaning the surface texture regularly. When you do that, your plastic wood decking will last longer. Note that how long your composite decking last depends on whether you follow best practice when installing the decking boards. You should take care of your composite decking regularly. This you should do by making sure that dirt does not stay long on your composite decking surface.

 If you spot mud on your deck, you should first sweep it with a broom and then use a cloth that you soak in water to wipe the dirt off. If you spot oil or grease on your composite decking, you should look for a soft brush and thoroughly scrub the surface after you have poured soapy water on it. You don’t have to let oil spill on your plastic wood decking in the first place. This will save you the stress of scrubbing and scrubbing your decking. The same thing goes for mould and mildew. 

To prevent mould from growing on your decking surface, you have to clean it regularly. When you sweep the top of your outdoor patio, you will spot algae and quickly remove it before it becomes a threat to safety. What happens if green algae or moss have grown on your composite decking? Don’t lose hope yet; you can still remove the green algae.

Removing Algae from Your Composite Decking

how to remove algae from your outdoor decking

Algae growing on your composite decking can be detrimental to the durability and the lifespan of the decking. The wrong side of algae is that it spread quickly. That is why you have to take steps to remove algae from your decking surface. How do algae grow on your composite decking?  

Algae will thrive on your decking when leaves and pollen accumulate on top. If moisture should come in contact with the decaying leaves, it will create a perfect breeding ground for green algae to sprout. If you don’t remove the green algae, your composite decking surface will become slippery. This will make it unsafe for you to walk on your plastic wood decking.

Steps to Remove Algae from Your Composite Decking

Step One – Get Your Cleaning Kit

What you will need to remove algae from your composite decking include a soft brush, soap or deck cleaner, water, power washer or a water hose. Note that you can use any that is readily available. Also, please ensure that you use a soft brush when cleaning because a stiff brush will scratch the surface of your plastic wood decking.

Step Two – Mix the Soap and Water

Look for a bucket and fill it with one-gallon water. You should pour the soap into the water and mix thoroughly with your hand until it foam. Please ensure that you wear a glove when mixing the soap with the water. Some will recommend that you add ¾ cup of chlorine bleach to the solution. You can add it if you want to, but we don’t recommend bleach.

Step Three – Remove the Algae

Before applying the soapy water to the algae, we recommend that you try to remove it first. This you can do by scrubbing it with a brush. Although this will not remove all the algae, it will make your task easier.

Step Four – Apply the Solution

You can spray the soapy water on your composite decking if the algae are scattered all over your decking. If it is just in a spot, you can pour the water on the area. You should wait for 10-15 minutes so that it will soak into the algae that you want to remove.

Step Five – Scrub Your Composite Decking

After you have waited for about 15 minutes, you can scrub your plastic wood decking with your soft brush. You should scrub along the grain of your composite decking boards. Scrub thoroughly until every trace of algae is no more.

Step Six – Rinse Your Composite Decking

When you are confident that you have removed all the algae from your plastic wood decking surface, you can rinse it with water. You can do that manually by pouring water on the surface, or you can use a power washer. When you are using a power washer, it is best to use a fanning nozzle because it will not let the pressure of the rushing water damage the surface of your decking.


You can remove algae from your composite decking if you follow the steps we outlined in the write-up. Also, ensure that you clean your plastic wood decking regularly to prevent algae from growing on it.

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