Ultimate Guide to Maintaining & Cleaning Your Composite Decking

So, you’ve either just installed your new composite decking or you’re doing a bit of research into what it takes to look after it. We understand that keeping your deck in top condition is a priority. That’s why we’ve poured our years of hands-on experience and customer feedback into this ultimate guide.

We’ll cover everything from crucial post-installation checks and the best cleaning techniques, to insider tips for removing stubborn stains and a clear list of which household products to avoid. Most importantly, we’ll explain how the specific type of decking you own determines the care it needs.

We’ve packed a lot of practical advice into this guide, so to help you get straight to what you need, use the “Jump To” menu below. We’ve also included helpful videos in each section—perfect if you prefer a visual guide!

Identify Your Decking
Post Installation
A Proactive Guide
Basic Clean
A Long Waited Clean
Clean Stubborn Stains
Removing & Repairing
Conclusion
Customer FAQs

Identify Your Decking Type Before Maintenance

First, let’s identify which type and generation of composite decking you have. This is key because it determines how much cleaning is needed and what products you should use.

First Generation: What to Know

This is the classic and most common type of composite decking sold in the U.K. The top surface is produced using reclaimed wood fibres. Why does this matter? Well, with anything that has wood in its structure, regular cleaning is essential to stop the build-up of algae, mould, and mildew.

Yes, first-generation composite decking can get mould and mildew if dirt, debris, and water are left on the surface for long periods. If this has already happened to your deck, don’t worry! Just jump to our deep clean section to see our tips on how to remove it.

Grey first generation composite decking board

First generation composite decking board reversible wood grain and thin grooved

Second Generation: What to Know

Also known as capped, shielded, or protected boards, this type is the ultimate high-performance, low-maintenance option. As we’ve mentioned across this website, these boards are manufactured with a thin plastic layer that covers the entire board, acting as a protective shield.

This shield increases resistance to moisture, which is key when it comes to cleaning. Since the boards resist moisture, they aren’t a breeding ground for mould and mildew, although they can still get a build-up of algae. They are also more resistant to staining. Therefore, regular cleaning is all that’s required to prolong the enhanced appearance of your composite decking

Reversible Dual Colour Composite Decking Board In Graphite Grey & Silver Grey

Dual Colour Teak & Mocha With Circle Hollow Core

Reversible Dual Colour Mocha & Teak Composite Decking Boards

Post-Installation Maintenance Checks

It makes sense to start with maintenance, right? If you’re searching for advice or have just purchased your decking, following some of the tips we’ve learned over the years can decrease the level of cleaning required during the product’s service life. Let’s take a look.

Maintenance Starts Right After Installation

Once your composite decking is installed, we recommend checking the following key points:

Check the gradient	Check gaps	Check the flex
There should be no water pooling on your deck. Pour a bucket of water or use a garden hose to test it. All water should run off smoothly. If any water sits on the surface, discuss this with your fitter or re-check your installation guide	Checking the gaps is essential for drainage and expansion. Go around your deck and confirm that the end-to-end gap is 6mm and the side-to-side gap is 3mm. If the gaps are incorrect, contact your fitter immediately.	Walk across the entire decking and check for any noticeable flex or bounce. This is a clear sign that the joist centres are not at the recommended 300mm and needs to be investigated urgently.

Once these checks are complete, what else should you know to reduce the amount of cleaning required and keep your deck looking its best?

A Proactive Guide to Preventing Issues

Preventing Mould & Mildew

Despite the fact composite decking has resistant qualities to mould and mildew due to its composition, which ensures a reduction in moisture absorption; composite boards can still experience growth of mould and mildew when the accumulation of leaves and debris build up on the boards. When debris, such as leaves, fall onto the deck and pile up, this creates a barrier on the deck surface, which traps the moisture and heat in an insulating layer. Mould and bacteria thrive within these conditions and, in turn, are more likely to grow when left on your decking.

Therefore, the location of your decking is important to consider in the maintenance of your composite decking. For example, if you place your decking under trees and bushes, you will need to clean your decking more regularly. Mould is not only an eyesore but will also damage and weaken your composite boards, which can lead to the costly and time-consuming process of having to replace or reinstall boards.

As stated above, regular checking of the condition of your decking boards is important, as mould can spread and ultimately damage multiple boards if left untreated. In most cases, mould and mildew can be simply cleaned with hot soapy water and a soft bristle brush. For tougher stains, you can attempt to use a vinegar and baking soda solution, resorting to stronger products such as Compo Clean if all else fails.
Avoid water standing on my decking?

Composite decking is a water-resistant material, but this does not mean it won’t absorb moisture if fully submerged in water. Composite decking repels more water than wood but is not completely waterproof. To properly care for your composite decking, avoid any build up of water on the deck surface and ensure water drains off the deck easily.

Pro tip: Run a bucket of water or a hose along your deck to test the drainage. All water should run off smoothly.
Cleaning Food Spills Immediately

Most homeowners use their decking as an outdoor eating area, especially in the summer months. Food particles on your deck surface can make it look less attractive and cause staining. It can even cause stains and the growth of mould to grow on your deck. Whenever you have your meal on your deck, ensure you don’t leave food scraps on the deck. Check around and clean away any food scraps to prevent mould growth.

Pro tip: A quick wash with hot, soapy water immediately after any spills or grease drops will ensure your deck stays looking its best.
Avoid Scratches on the Decking

When there are scratches on your decking, it can distort the decking’s appearance. Scratches can also be difficult to fix on composite decking. Although composite decking is a quality material, it is still prone to scratches. Avoid dragging items such as furniture and BBQs over your decking or placing objects with sharp edges on your composite decking in order to protect the decking surface.
Remove Oil and Grease Stains

Another composite decking maintenance tip is to remove stains on the decking surface. Homeowners using their decking as a cooking and dining area should always check for grease stains. If you notice an oil or grease stain on the decking surface, clean it immediately. Remove the grease stain with vinegar and baking soda. Use the baking soda and vinegar mixture to gently scrub the affected area with a decking brush.
Get Rid of Leaves

A build-up of dead leaves and twigs on your composite decking traps moisture leading to mould and bacteria growth on the composite boards. It is important to remove leaves and twigs to avoid this from occurring, as mould can stain and damage your decking.

Pro tip: A simple sweep with a soft-bristled brush is the easiest way to remove dry leaves. For wet, stubborn leaves, hose the area down first to make them easier to brush away.
Warning: Avoid Using Bleach

When mould or tough stains appear, many homeowners are tempted to use bleach. Based on our experience, this is one of the most damaging things you can do to your deck. Chlorine bleach is far too harsh for composite materials and will cause significant problems.

Firstly, it will permanently fade and strip the colour from your boards. Secondly, it is corrosive to the metal clips and fasteners holding your deck together, which can compromise the structural integrity of the entire deck over time. Finally, bleach is surprisingly ineffective at killing mould on porous surfaces like composite decking, meaning the problem will likely return.

For a safe and effective clean, stick to a simple solution of ammonia-free washing-up liquid and water. For more stubborn stains, the targeted use of vinegar and baking soda is the correct approach.
Avoid Placing Hot Objects on Your Decking

Placing a hot object on decking can distort its appearance. If you plan to use your decking area as a kitchen, avoid placing hot objects directly on the deck’s surface. Grills and BBQs can damage or create dents on the decking surface. Remember that composite decking differs from wood, as it is made from recycled plastic and wood fibres. Hot objects placed directly on the surface will distort or dent your decking.

Please Note: Outdoor rugs are a great way to protect high-traffic areas and ensure hot objects don’t sit directly on your deck’s surface.
Using An Outdoor Rug From The Start

Ideally, you will not have to fix any markings from your decking surface if you prevent them from occurring in the first place. You can protect your decking from marks by using rugs or mats. Placing them on areas of your decking that experience the highest footfall can prevent scuff marks from shoes and high heels. Choosing lightweight furniture will also help to prevent scuff marks on your decking. Use rubber furniture pads on the legs of your furniture to protect the deck surface.

How to Perform a Basic Clean Of Your Composite Decking

Now that we understand the differences between board types, let’s look at the basic, regular cleaning needed to keep your composite decking looking its best.

Step 01:

Remove all furniture and other items from the surface.

Step 02:

Fill a bucket with lukewarm water and add a few squirts of ammonia-free washing-up liquid.

Step 03:

Take a soft brush (we recommend one you would use to clean a car), dip it in the bucket of hot soapy water, and simply scrub the deck clean.

Step 04:

Give the deck a good scrub, going over any tougher areas multiple times.

Step 05:

Once you’re happy, simply hose it down. You can use a power washer on a spray setting, but do not get too close or use high pressure.

Remember, with a pressure washer, do not get too close (hold it at least 12 inches away) and do not use a high-pressure setting.

If you do this regularly (around once a month), you likely won’t need a deep clean.

A long waited clean of your composite decking

If you have left your deck for some time without regular monthly cleaning, it will likely have built-up marks, dirt, and debris. Much like a car that is only cleaned once or twice a year, the process will be longer. However, in most cases, the deck can still be brought back to its best by following the steps above.

Seasonal Care: How to Handle Winter Snow & Ice

It is important not to leave snow on your composite decking during winter, as it can form ice and become slippery. Removing the snow will also ensure that moisture does not get trapped on your decking and become a breeding ground for mould and algae. When clearing snow, you want to do it carefully so that it won’t cause damage.

Ways To Remove Snow From Composite Decking

Sweep the Snow

An easy way to remove light snowfall from composite decking is with a soft bristle brush. This method will prevent the possibility of scratching the surface and won’t damage your boards.

Use a Plastic Shovel

A plastic shovel is a good tool to remove a large amount of snow. However, when using any shovel, you must do it with extra care to avoid scratches. It is important to always shovel parallel to the decking boards, not perpendicular. This will reduce the chances of the decking getting scraped.

Try a Snow or Leaf Blower

You can use a snow or leaf blower to remove light snow from the composite decking. These are excellent for clearing a thin layer, but you should use them with caution to avoid any damage.

Applying Ice Melt

You can also apply ice melt on the decking before the snow falls to prevent ice from forming, or directly on top of the ice to melt it. When choosing an ice melt, choose a kind that is not harsh.

Expert Tip: We recommend a calcium chloride-based ice melt for composite decking. Ensure that the ice melt you use does not contain added colourants. Avoid using rock salt.

How to Deep Clean Stubborn Stains & Mould

What can you do if you have followed the processes we’ve shared, but you are still left with marks or scratches? Here, we can share our experience from supporting customers and offer advice on tips we’ve learned. These are some of the successful methods we’ve seen over the years.

Using Vinegar

Adding water into bucket hot soapy water

Using Vinegar
Vinegar is an excellent degreaser, but its acidic nature means you need to be careful. From our own testing, we’ve found its effect depends heavily on your type of decking.

Important Note: On first-generation composite boards, vinegar can begin to affect the colour if left for over 30 minutes. On capped (second-generation) boards, the protective layer provides much higher stain resistance.

How to use it safely:

Apply a small amount of white vinegar directly onto the stain.
Let it soak for a few minutes to break down the mark.

Crucially, once the mark has lifted, wash the area thoroughly with warm, soapy water to neutralise the acid, and then rinse with clean water.

Scrub the area gently with a soft-bristle brush.

Using baking soda

Baking soda is a mild abrasive that is perfectly safe for composite decking and works especially well on surface mould and grime. The success we’ve seen with this method makes it, along with vinegar, our go-to solution for stubborn stains.

How to use it effectively:

Sprinkle a generous amount of baking soda over the stained area.
Use a soft-bristle brush and a little water to scrub the powder into a paste.
Let the paste sit for around 15-20 minutes.
Rinse the area thoroughly with clean water until all residue is gone.

Using Baking Soda & Vinegar Together

Grey picture frame composite decking with raised hot tub and bar

The combine method using vinegar and baking soda together must be done correctly, otherwise the two will neutralise each other.

For the most successful way use a baking soda paste, its safe and an effective option. Follow this two-step process:

Create a thick paste using baking soda and a small amount of water. Apply it to the stain and let it sit for 15-20 minutes.
After it has sat, lightly spray the paste with white vinegar. The fizzing reaction will help lift the stain.
Gently scrub the area with a soft-bristle brush and then rinse the deck thoroughly with clean water.

Pro tip: Start scrubbing with a soft brush as soon as the fizzing begins—this is when the combination is most effective. Remember, never pre-mix the ingredients in a bottle thinking it creates a “super-strength” cleaner; this actually neutralises them and makes them ineffective.

How to Repair Scratches, Scuffs, and Marks

When it comes to removing or repairing a composite decking board there are several ways in which you can do this but first its important to understand what type composite decking you have as this can make or break in the success or removing or repairing you boards.

First generation boards

Grooved finish

The first-generation grooved board is probably the easiest board from which to remove a scratch, scuff and marks. Try using stainless-steel wool or fine sandpaper to lightly go over the scratch in the direction of the grooves. Be careful not to press too hard when using this method, we recommend using light pressure only. This can lighten the colour of the board over time; however, the board will weather over time and the lighter colour may not be as apparent.

Pro tip: Always sand lightly in the direction of the grooves to avoid damaging the board texture.

Wood grain finish:

On a first-generation wood grain board, the above method can also be used. However, this can result in buffing away the wood grain texture and removal of colour. The colour can be brought back using a composite colour reviver. When using a colour reviver, use a small paint brush only on the affected area. This may not be a perfect fix and may require time for the board to weather for the area to blend with the rest of the board.

Second generation boards

Using heat Guns:

As capped boards aren’t a wood fibre based surface wire brush and other methods will only damage the surface further, your best way of removing or repairing scratches, scuffs, and marks is by using a heat gun. This is one of the most effective ways to eliminate the scratches on a second-generation composite decking board, however, this also requires a lot of practice.

Failing to do this properly, will result in permanently damaging your boards with burn marks. To begin removing the scratches, find the marks and heat them using the heat gun. Be careful not to hold the gun too close or hold this on the mark for too long. Once the area has been heated; this may leave some areas darker, these can disappear after a few weeks of natural fading.

If you feel more comfortable using an already made repair kit, these are available. The repair kits use wax fillers, applying the wax and rubbing into place. Remove any excess wax quickly.

To touch up scratches and marks, you can use a composite repair marker pen, use like a pen to go over the scratch, this method is less effective in creating a seamless finish.

Using Magic Eraser:

Another method that many suggest is using a Magic Eraser or melamine foam. Melamine foam sponges have micropores that trap even the most persistent stains. However, due to their abrasiveness, they can damage composite decking if used too harshly. It can remove the grain patterns and textures from your decking boards. They do work when used correctly, if you rub too hard and too much you will damage your board.

For best results simply rub softly and slowly and continue clean away as you do this. See the video for visually details.

Wood grain grey decking with dark edge under pergola

Decking Repair Kits:

Another option that you can try is to use decking repair kits. They are often composed of fillers, either wax or epoxy-based, applied directly to the cuts and scratches. Lastly, some suppliers advised using a wood stains that match the colour of your decking, to reduce or remove marks or scratches, however, from our testing, this does apply to first-generation composite boards, but after several months, it starts to flake..

Conclusion

In summary, proper care for your composite decking comes down to three key principles: performing crucial post-installation checks, committing to simple and regular cleaning (ideally once a month), and using targeted methods for any tough stains. Our years of experience have shown that this preventative approach is the easiest way to ensure a long and enhanced life span for your decking. Of course, the best way to guarantee low maintenance is to start with high-quality materials. If you’re planning a new project or considering an upgrade, explore our range of second-generation composite decking to find the perfect fit for your home.

Raised Anthracite Grey Composite Decking With Steps & Hot Tub

Anthracite Grey Wood Grain Composite Decking With Hot Tub

Customer FAQs

1Can you use Vinegar & Baking Soda?

Yes, these natural products can be used carefully for grease and oil stains that won’t come off with ordinary washing-up liquid.

Remember wait until the fizzy then clean, don’t pre mix as this will neutralise the effect
2Should I Brush Away Dirt and Debris?

Absolutely. Brushing your decking regularly removes the dirt and debris that can lead to mould. Remember to check the gaps.
3Can I remove bird droppings from my decking?

Yes. To remove them safely, first rinse the area thoroughly with a garden hose to soften the droppings. Then, apply a little washing-up liquid and use a soft-bristle brush to gently scrub the stain away. Never use a sharp object to scrape the surface, as this will cause scratches. Finish by rinsing the area completely.
4How often should I clean my decking?

We recommend a regular clean (around once a month) to maintain its appearance. If your deck is under trees, it will need more frequent attention.

Remember If you clean once a month this will ensure you deck stay looking its best
5Can I put a BBQ on my deck?

Avoid placing hot objects like BBQs or grills directly on the deck’s surface, as the heat can distort, dent, or damage the material. Use a protective mat.

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