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Is Composite Decking Slippery When Wet?

Like most surfaces, composite decking can become slippery, especially when wet. That said, good-quality composite decking produced to high standards are specifically developed with anti-slip properties built-in (not slip-proof). Nevertheless, care should always be taken with any wet surface underfoot. Nobody wants to slip on their deck and injure themselves, as these accidents can become painful and expensive. So, to prevent this, we will discuss how you can minimise the slipperiness of your decking. Moreover, we will cover why decking becomes slippery and how the generation of a board impacts the slipperiness of composite decking.

Reasons Why Your Composite Deck Might Be Slippery

Knowing the reasons why they may be accident-prone can help you prevent any injuries. If you know why decking becomes slippery, you can take countermeasures to make it safer for you and your family. Here are the top reasons why composite decking becomes slippery over time.

Dirt and debris 

As time passes, fallen leaves and dirt can accumulate on your decking. Leaving them for long periods can pose a safety problem for you and your family. Not only does this look unclean, but it also promotes the growth of mould and algae. The main reason decking becomes slippery is the growth of mould and fungus. While these can’t naturally grow on your capped composite decking, they can grow on uncapped composite boards, fallen leaves, dirt, and debris. When left on your decking, the mould that forms on dirt and debris can transfer onto your decking, creating a more slippery surface.

Winter season 

During winter, all decks will become slippery, no matter what material is used. When there is an accumulation of both ice and water on your composite decking, it will become slippery. Attempting to remove ice from your decking can be difficult, resulting in your boards becoming damaged if done incorrectly. To prevent this from happening, we advise you to use non-abrasive cleaning methods like a plastic shovel to remove the ice or do not attempt to remove it; instead, let it evaporate in its own time.

Non-anti-slip composite decking

If your composite decking is quite old, the chances are that it gets more slippery than the newer generations of composite. Older generations of composite decking tend to absorb moisture faster, leading to the development of moulds and moss, which are slippery.

Generations of composite boards

The slip resistance of your composite decking boards is dependent on the generation of the board. Please read on to find more information on how the slipperiness of your deck is affected by the generation of your board.

Early Generation

The early generations of composite decking were undeniably slick, but the material has been modified and upgraded into the slip-resistant options we have today. The early generations of composite decking brought about its reputation for being slippery. So, if you have an early-generation composite deck, then this will result in your decking becoming more slippery.

First Generation

First-generation composite decking boards are made from shredded wood fibres and recycled plastics. The slip resistance of a first-generation board varies depending on the quality of the board, the surface finish etc. However, it is important to note that our first-generation boards have been rated low or medium risk of slip. Some boards in our exclusive range of composite decking boards are more slip resistant than boards in our home choice premiere range. 

All of our first-generation composite decking boards have been tested for their slip resistance, allowing us to determine a value for their slipperiness using the equivalent pendulum test value (PTV). These tests have been carried out to ensure our composite decking boards are safe for commercial projects such as motorway services that have decking outside. These tests ensure that the boards are safe and can withstand heavy footfall. If a board scores higher than 36+ PTV, then it is classed as a excellent resistance to risk of slip. If a board score is between 25 and 36 PTV, it is classified as a good resistance in risk of slip. If a board scores anything below 25, it is classified as having a high risk of slipping. All of our first-generation boards score 27 or above, highest being our grooved finish with a PTV of 45, meaning our boards offer excellent to good resistance of slipping.

Please note our test was carried in very wet conditions not wet conditions, our choosing for very wet is to provide a true reflection in very wet British weather conditions.

Second Generation

There is little difference in slip resistance between first-generation and second-generation boards. All of our second-generation boards have met EN standards. Intertek conducted this test to determine whether the composite decking boards are safe. All of our composite decking boards met the standard, meaning they are safe for your project.

To sum up, there is little difference in slip resistance between our first-generation and second-generation boards. The important thing to take away from this is that all of our boards have met the minimum slip resistance requirements on PTV and EN standards. This means you do not have to worry about your safety on the decking compared to if you had a wooden decking laid down. It is a common misconception that composite decking is as slippery as wooden decking; however, this is not the case. Composite decking is a lot less slippery than wooden decking.

Ways to help prevent your deck from becoming slippery

Fortunately, there are multiple ways you can prevent your deck from becoming slippery. One way to keep your decking slip-resistant is to clean it regularly.

Keep your composite decking clean by removing fallen leaves, pollen, dirt, and debris as soon as possible. You can do this by sweeping your deck with a brush. We recommend that everybody does this as a minimum to maintain your deck’s appearance and to ensure it is safe.

Take a look at how you can prevent your deck from becoming slippery.

Keep your composite decking dry.

Although composite decking absorbs minimal moisture, any surface water can still be a breeding ground for mould and algae. Moisture can accelerate mould growth. Therefore, we advise you gently sweep any surface water off your deck immediately. If you have ice or snow accumulating on your deck, make sure to use non-abrasive removal methods.

Ensure proper drainage of the decking

When installed correctly, composite decking should allow for the proper drainage of rainfall. Make sure to keep the spaces between the decking boards clean to allow water to flow to the ground easily. This will prevent any water from pooling on your decking. Water on the surface of your deck will promote the growth of mould, which will result in your decking becoming more slippery.

Consider using grooved/textured decking boards.

If you plan to build a new deck or replace old decking, consider purchasing grooved or textured composite decking boards. Embossed and grooved composite decking boards offer better friction, helping to improve slip resistance.


In conclusion, composite decking will become slippery, especially when wet. Make sure to keep your composite decking clean to reduce slipping. Do a thorough deep clean of your decking at least four times a year. Although it is a low-maintenance type of decking, it still requires some maintenance. Ensure the correct installation of your composite decking has been performed to the manufacturer’s guidelines so there is no water pooling. Also, pay close attention to drainage and keep the decking area dry. If you follow this guidance, your decking will be as safe as possible.

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