How To Make Composite Decking Less Slippery

Composite decking is a type of building product that is made from a mixture of wood, plastic, and bonding agents. While many are more slip-resistant than other decking materialsOpens in a new tab., they can still be pretty slippery when wet – so how can you stop this? 

If you have found your composite decking to be too slippery to use, then this is the guide for you.

How To Make Composite Decking Less Slippery

Here, we are going to be taking a look at how composite decking becomes slippery and what you can do to tackle this. This way, your composite decking will be much safer to use. 

So, let’s dive straight in! 

How Composite Decking Can Become Slippery

Before we start looking at all the ways you can make composite decking less slippery, we need first to understand what makes composite decking so slippery, to begin with. 

Most good quality composite decking comes with a traction-enhancing cap to help increase friction, but it doesn’t completely stop slips and slides.  This means that composite decking can become very slippery – to the point that it becomes a serious hazard!  

So, let’s take a look at all the things that can cause composite decking to become slippery. Take a look and keep this in mind so you know when your composite decking is likely to be slippery before you step outside. 


Moisture is one of the most common reasons why composite decking may become slippery. In truth, this is true for pretty much any type of surface – if it gets wet, it’s much more likely to become slippery. 

This is because of a lack of friction. Friction is the resistance between two surfaces that prevents sliding.

Water reduces friction, meaning that there’s less resistance between the two surfaces, and it’s easier for them to slide.

This means that the more water that’s on a surface, the less traction it has and the more slippery it becomes – and this is what happens when composite decking becomes wet. 

Composite decking can become wet due to rainfall or whenever you hose it down to clean it. Even if you spill a drink, your composite decking will become slippery where the liquid was.

Because composite decking is made of both natural wood fibres and plastic, it is highly water resistant but not completely. This means that puddles are likely to form during rainfall and remain for longer than compared to wood decking. 

Frost and Ice

If you live in colder climates, it’s likely that you’ll see your composite decking covered with frost, ice or even snow during the winter. Because frost, ice, and snow are all made from water, they also reduce the traction of your composite decking and make it very slippery. 

So, take great care when stepping outside on your composite decking during cold weather and the winter season! 


As it’s likely your composite decking is outdoors, it’s also likely that you will see plenty of outdoor debris fall and remain on your decking. This includes things like leaves, twigs, dirt, sand, and tiny rocks or gravel. 

All kinds of debris can cling to our shoes or pets’ hair, and they can be tracked all over your composite decking.

They reduce the traction of your decking and can become slip or trip hazards. So, if your composite decking is slippery, it may not be the decking itself, but what’s on it instead! 

Mould and Algae

One of the benefits of capped composite deckingOpens in a new tab. is that it is much more difficult for things like mould, moss, mildew, and algae to grow on its surfaces – but it’s not impossible.

The plastic materials used to help make composite decking make it much more difficult for organisms like mould and algae to grow and thrive, which is part of the reason why composite decking requires much less maintenance than wooden decking. 

However, exposure to high levels of moisture and the presence of plenty of debris like leaves means that your composite decking could become the ideal environment for mould and algae.

Specifically, uncapped composite can grow mould. My back steps in the shade are a good example of this. Without the protective polymer cap, the wood fibres our still exposed for the mould to grow on.

In this case, you may see mould and algae growth on your composite decking despite the low odds. 

These organisms can cause your composite decking to become slippery because they offer less friction. So, patches of your composite decking which feature mould or algae growth are going to be much more slippery than other parts of the decking. 

How To Make Composite Decking Less Slippery

So, now you know all the things that can make composite decking slippery. It should now be easier to work out what exactly is making your composite decking so slippery – and finding the right solution will now be a breeze! 

Here are some great methods to make composite decking less slippery. Some are more effective than others, depending on what is causing your composite decking to be so slippery in the first place.

So, find out what is causing your composite decking to be slippery, then use the recommended methods below! 

Solutions for Moisture Exposure

As most composite decking is outdoors, it’s very difficult to reduce the amount of exposure your decking has to moisture.

A great effective method is to somehow cover your decking by building a shelter above it – but this method is costly, time-consuming, and not always possible for all composite decking owners.

So, here are some tasks and products you can try out instead. 

Tasks You Can Do

If you can, it’s a great idea to improve any drainage around your composite decking. Make sure any drain pipes are working properly and that there are no breaks or blocks which can cause water to flow and puddle on your composite decking. 

There should be small gaps between the boards of your composite deckingOpens in a new tab. to allow for expansion or contraction when there’s a drastic change in temperature.

These gaps are also there to allow moisture and water to drain through the boards, but these gaps can become blocked by debris. So, regularly clean them out to prevent any build-up of water from forming on your composite decking. 

If there is any snowfall on your composite deckingOpens in a new tab., try to remove it as quickly as possible with a shovel. Ice forms underneath soft snow, and the longer the snow remains there, the more ice will build up. Removing it quickly prevents this. 

So, these are general tasks you can do to help prevent moisture and water from making your composite deck slippery – but there’s still more you can do. 

Products You Can Try

Moisture from rainfall or cleaning can cause composite decks to become slippery and these are unavoidable. Some solutions to this include using anti-slip tape, anti-slip coatings, anti-slip strips, and slip-resistant mats.

All of these things help increase the traction of your composite decking, so there’s more friction between your feet and the floor. However, each has its own advantages and disadvantages:

  • Anti-Slip Tape is extremely affordable and easy to lay down over your slippery composite deck. However, it’s difficult to remove, and you can only apply it to certain areas of the deck.
  • Anti-Slip Strips work in a very similar way but can only be installed around any steps. They also take a lot longer to install but are more durable and effective than anti-slip tape. 
  • Anti- Slip coatings refer to types of paint or sealer to give your decking more grip. They’re effective and help seal out moisture from your composite decking boards. However, they change the finish of your decking and can take forever to apply fully and dry. 
  • Slip-resistant mats are pretty affordable and don’t make any permanent changes to your deck, but they’re only effective for the parts they cover. If you want your whole deck to become less slippery, you will have to cover the whole deck with slip-resistant mats – and this can look pretty unappealing. 

All of these products can be easily found at retailers like AmazonOpens in a new tab., LowesOpens in a new tab., WayfairOpens in a new tab., Home DepotOpens in a new tab., and even WalmartOpens in a new tab.

Solutions for Mould and Algae

If you want to discourage mould and algae from growing on your composite decking, then there’s two main tasks you can do to achieve this – keep your decking dry and clean! 

How To Prevent Mold and Algae

Mould and algae love moist environments with plenty of food nearby. So, to stop them from growing on your composite decking and making it slippery, you need to protect your composite decking from moisture and clean it of debris regularly. 

Moisture, as we have already discussed, is a tricky one because not everyone can build a shelter over their decking.

Alternatively, you can use a waterproof coating to help prevent moisture from seeping into your boards. Unfortunately, this is time-consuming and will need reapplication every few years – but it certainly can help. 

Removing debris is very easy – just regularly sweep down your composite decking. In particular, you need to remove things that can decompose and become a food source for mould and algae, such as debris from plants and animals. 

You should also deep clean your deckingOpens in a new tab. once every two months to discourage mould and algae growth by using hot water and mild detergent. This will remove any smaller bits of debris as well as make the environment hostile for organisms like mould and algae. 

How To Kill Mold and Algae

If you already have mould and algae growing on your composite decking, then there are products out there you can use to kill them.

Most of the time, a deep clean using warm water and a mild detergent will kill the beginnings of any mould or algae infestations. However, if your case is too far gone, you will need a tougher mould cleaner to get rid of it. 

Mould and algae cleaners are very easy to source and generally affordable. They can be purchased from a range of retail stores (both online and offline), and all the equipment you need is a bucket and a mop (or a stiff broom).

Some you can apply directly to your composite decking, others require diluting with water – it all depends on the type of cleaner you purchase! 

Also, most mould cleaners are suitable for use on all kinds of surfaces, but we recommend you always check the instructions to make sure it won’t stain or damage your composite decking. 

Just follow the instructions on your mould cleaner, and soon, you will have mould and algae-free composite decking! 

Solutions for Debris

Removing debris from your composite decking is super easy. 

As we already mentioned, regular sweeping and a deep clean every two months will be enough to help lift all kinds of dirt from your composite decking.

Not only does this help prevent mould and algae growth, but it also makes your decking cleaner and more appealing. So, make sure you keep up this routine of cleaning your composite decking to reap the results. 

However, washing your decking down can make the surface slippery temporarily – so perhaps put down a slip-resistant mat or two to lower the risk of any slips or slides. 

Final Thoughts

A slippery composite decking can be dangerous but avoiding it is very tricky. 

There are easy tasks and products you can do to make your composite decking safer (such as installing anti-slip strips or regularly sweeping it off debris), but the biggest culprit behind slippery composite decking is moisture.

This makes fixing a slippery composite deck difficult because it’s almost impossible to stop rain from falling onto your deck! 

However, there are methods you can try – so check them out above! 

We hope this has helped you understand why your composite decking may be slippery and all the different methods you can try to fix it.

The important thing is to identify what is causing your composite deck to be so slippery and take steps to tackle it directly. Good luck! 

Ryan Nickel

A Red Seal carpenter, passionate about building decks to be enjoyed.

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