How to Clean and Seal Composite Decking – 2024 Guide

Due to its features and minimal maintenance required, composite decking has become a popular option lately. After all, when it comes to investing and redecorating any part of their home, people want to get a top-quality product, something that they will be able to enjoy, and more importantly, that will last them for many years to come.

Nevertheless, even though one of the main advantages, and therefore, why people decide on composite decking is that it is low maintenance, it doesn’t mean that it doesn’t need to be cleaned every once in a while. So, in this article, we are going to provide you with some cleaning tips, but firstly, you have to learn as much as possible about this type of decking.

What is it made of?


Since this is a fairly new product on the market, a lot of people aren’t sure about its composition. After all, you have to know these details because it is the only way to find the best cleaning method and supplies.

Basically, it is made of a combination of wood and plastic, as well as other materials. When it comes to the former it usually includes wood fiber, chips, and sawdust, but just like plastic, it can be made from recycled materials. In addition, during the manufacturing process, other compounds are added to it, so this type of decking is resistant to rot, which is what makes it so durable.

As you can assume, nowadays, there are multiple types of composite decking, and each of them has a unique design. Since we are going to discuss only cleaning tips, you can learn more about these on

Remove the debris, dirt, and stains


The first step you should take in this cleaning process is to remove all the debris from the decking. All you need for this task is water and a brush. Most people opt for using a garden hose and a scrub brush, which is okay, but keep in mind that cleaning everything thoroughly can take some time.

Instead, you can try using a power washer because it will not only facilitate this task and enable you to conclude it quickly, but it will also clean everything better. After all, it is crucial to be thorough, so take your time with this step, think about the tools you have at your disposal, and choose the best ones.

Avoid the bleach


A lot of people opt for using traditional bleach when they clean composite decking. Yes, it will kill the mildew, but keep in mind that it might not be quite effective when it comes to removing it from the boards.

To ensure that everything is perfectly cleaned, our advice is to use a so-called “safe cleaner.” These products are created specifically for this purpose, so they will remove all the mildew spores and dirt and ensure that the decking is spotless.

All you have to do is apply this solution, leave it for at least 20 minutes, scrub the entire area, and finally rinse it with clean water. As you surely know, mildew can cause numerous health issues over time, so this step is crucial.

Seal the deck


When it comes to this following step, it is completely up to you, but we still recommend that you seal the deck. Why? Well, by cleaning and sealing it properly, you won’t have to worry about the maintenance tasks for quite some time.

If, however, you don’t want to do this, keep in mind that you will have to thoroughly clean the composite decking more often, probably at least once a year. So if you want to enjoy all of its benefits, you should go with this step.

Choose the right sealer


Obviously, the first thing you have to do is choose the sealer, and finding the best one is of crucial importance. First things first, our advice is to opt for a water-based product, and there are two reasons for this. Firstly, these products are crystal clear, meaning that they won’t, in any way, alter the color and appearance of the decking. Secondly, some of these use synthetic resins, which will prevent the mildew from developing. Finally, you should also choose the one that contains zinc, which is another powerful weapon in the battle against decay.

Read the instructions

For some reason, many people do not read the label on the product they are about the use. This is true for any kind of merchandise, but you must do it when it comes to sealing composite decking. After all, it is the only way to ensure that this project turns out perfectly.

Plus, just by reading this label, you will get the answers to all the questions you have – How many coats should you apply? What should be the time between applying them? How much time does it need to dry completely?

Don’t forget to brush


When it comes to applying the sealer, you can either go with the rolling or spraying method. Nevertheless, regardless of this, you cannot skip the brushing part. You have to do this while the surface is still wet. Why? Well, simply because it is the only way to ensure that the sealer has penetrated every pore of the wood. This absorption process is crucial because by doing this, you can rest assured that the decking will last you for a long time.

Wipe off the excess

One of the most common mistakes that people make isn’t that they apply too much sealer in some areas, but it is that they do not remove it. If you were to leave it just like, not only would it disturb the appearance of the decking, leaving shiny stains, but also, those spots are likely to peel in the future, and therefore, creating another problem that you would have to deal with.

Let it dry and enjoy


Upon completing the previous step, your job is done. Now, all you have to do is give it some time to completely dry, and that’s it. You have completed your project successfully and prolonged the lifespan of your composite decking. Naturally, you should still clean it to remove the dust and debris every once in a while, just to ensure its aesthetics.