How to restore composite decking boards? A practical step-by-step guide.

Why is it worth renovating composite decking boards?

Although composite does not require annual treatment or painting like timber, regular care and renovation significantly extend its lifespan and improve its appearance.

What are the benefits of renovating composite decking?

• Restores the original colour and surface texture

• Removes stains, moss and streaks

• Protects against further fading and discolouration

• Improves safety – surfaces are less slippery

• Refreshes the look of the terrace without costly replacement

When should you renovate composite decking boards?

You don’t have to wait until the terrace looks terrible. Here are a few signs that it’s time to renovate:

• Faded colour and a dull surface

• Visible dirt that does not come off with ordinary washing

• The appearance of mould, moss or fungal growth

• Grease stains from barbecues or oil

• Scratches and minor surface damage

It is worth freshening up your terrace once a year – preferably in spring or autumn.

How to renovate composite decking boards: step by step

Get ready for a bit of physical work, but the end result will be worth it!

STEP 1: CHECK THE TECHNICAL CONDITION.

Before you start cleaning, inspect your terrace carefully:

• Are there any cracks or gaps?

• Are the fixings secure?

• Are there any signs of the material delaminating?

• Are all the boards securely screwed down?

If there is serious damage, consider replacing individual boards before renovation.

STEP 2: BASIC CLEANING.

For basic cleaning, you can use:

• A pressure washer (up to 100 bar – not too powerful!)

• A stiff-bristled brush

• A bucket of water and WPC cleaning solution

Recommended cleaners for composite decking boards:

• HG Taras Cleaner

• Osmo WPC & BPC Cleaner

• Bona Outdoor Cleaner

• Eco-friendly homemade solutions (e.g. water with vinegar and baking soda)

Warning: do not use strong detergents or bleach – they may permanently damage the surface structure.

STEP 3: REMOVING DEEP-SET DIRT AND MOULD.

If moss, algae or grease stains have appeared on the surface, you will need stronger products:

• Products such as anti-algae treatments 

• Special degreasing products

Apply the product according to the manufacturer's instructions, leave it for a few minutes, then rinse with water.

STEP 4: SANDING (optional).

If the boards have prominent scratches, discolouration or dull patches, you can sand them lightly with sandpaper (grit 150–180). But take care – only do this with solid composite decking boards, not hollow ones!

Do not sand too hard – the aim is just to smooth the surface slightly.

STEP 5: PROTECTION AND COLOUR REFRESHING.

After cleaning thoroughly, you can apply a protective treatment or colour refresher.

Application:

• Apply a thin coat to a clean, dry surface

• Spread with a brush or cloth

• Leave to dry according to the manufacturer's recommendations

• If necessary, repeat after a few hours

The result? The boards look like new again, and the colour gains depth.

What should you avoid when renovating?

• Do not use chlorine, bleach or strong acids – they can permanently damage the surface
• Do not paint composite decking with wood paint – it does not adhere well
• Do not use angle grinders – you could damage the board's texture
• Do not leave cleaning products on for longer than recommended – they may discolour the surface

How should you care for your deck after renovation?

• Wash the boards regularly – ideally every 1–2 months

• Clean gutters and drains to prevent water from pooling

• Clear away leaves and organic debris – this prevents mould growth

• Use pads under furniture to reduce the risk of scratches

• Avoid placing a barbecue directly on the board – grease is the enemy of composite decking!

How much does it cost to renovate a composite decking board?

Here are the estimated costs for 2025: