Composite Decking: The Complete UK Buyer's Guide

Composite decking has become an increasingly popular alternative to traditional timber decking for UK gardens, patios and outdoor living spaces.

It offers the appearance and texture of timber without many of the ongoing maintenance requirements associated with wooden decking. There's no annual staining or painting, and good-quality composite boards can create a smart, contemporary outdoor surface that works particularly well with modern garden designs and aluminium pergolas.

But not all composite decking is the same.

You'll encounter different board constructions, capped and uncapped boards, hollow and solid profiles, different lengths, colours, fixing systems and price points.

This guide explains what to look for before buying composite decking and helps you decide which type is right for your garden.

What is composite decking?

Composite decking is an engineered decking material generally manufactured using a combination of wood fibres and polymer materials.

The aim is to combine some of the natural appearance of timber with the durability and lower maintenance requirements of modern composite materials.

Unlike traditional timber decking, composite boards don't normally require routine painting, staining or sealing.

Modern boards can also feature embossed woodgrain surfaces that give the decking a much more natural appearance than earlier generations of composite decking.

What are the advantages of composite decking?

For many UK homeowners, the biggest attraction is reduced maintenance.

Traditional timber decking can require regular cleaning, staining, painting or sealing to keep it looking its best.

Composite decking generally requires considerably less ongoing treatment.

Some of the main advantages include:

• No routine painting or staining
• Low ongoing maintenance
• Woodgrain appearance
• Resistance to moisture and decay
• Consistent appearance
• Choice of contemporary colours
• Hidden fixing systems available
• Suitable for modern outdoor living areas

Composite decking can therefore be particularly attractive when creating an outdoor space that you want to enjoy rather than continually maintain.

Composite decking vs timber decking

Both materials have advantages.

Natural timber has an authentic appearance and can be relatively inexpensive initially, depending on the species and grade selected.

Composite decking generally costs more than basic timber decking but requires less ongoing treatment.

One of the biggest differences is maintenance.

Wooden decking may need to be stained, painted or sealed periodically. Composite decking doesn't normally require these treatments.

For homeowners creating a long-term outdoor living area, the reduced maintenance can make composite particularly attractive.

We'll be covering this in much greater detail in our Composite Decking vs Wood Decking guide.

What is capped composite decking?

Capped composite decking has an additional protective polymer layer around some or all of the composite core.

This outer layer can provide additional protection against staining, moisture and fading.

Premium capped decking is therefore often positioned at the higher end of the composite decking market.

What is uncapped composite decking?

Uncapped composite decking doesn't have the additional protective polymer shell found on capped boards.

Instead, the composite material itself forms the exposed surface of the decking.

Good uncapped composite decking can provide an attractive and cost-effective alternative to timber while retaining many of the advantages associated with composite materials.

It can therefore be a particularly attractive option for homeowners looking for the appearance and convenience of composite decking without moving into the price bracket of premium capped products.

At PergoLIFE, our initial composite decking range uses an uncapped woodgrain composite board designed to provide excellent value for UK garden projects.

Hollow vs solid composite decking

You'll also come across hollow and solid composite decking boards.

Hollow composite decking

Hollow boards contain engineered cavities running through the profile.

This reduces the amount of material required and can make boards lighter and easier to handle.

For many domestic garden decking installations, a properly engineered hollow board provides an excellent balance between strength, weight and cost.

Solid composite decking

Solid boards contain considerably more material and can therefore be heavier.

They may be preferred for certain applications, but this doesn't automatically mean that every solid board is superior to every hollow board.

Board design, material composition, joist spacing and correct installation all contribute to the performance of a finished deck.

What colour composite decking should I choose?

Colour can completely change the appearance of an outdoor space.

Two of the most versatile choices for contemporary UK gardens are natural oak and grey.

Natural Oak composite decking

Natural Oak creates a warmer appearance that works particularly well with planting, timber-effect finishes and gardens where you want to retain a natural feel.

It can also create an attractive contrast against anthracite aluminium pergolas and darker garden furniture.

Grey composite decking

Grey decking produces a more contemporary architectural appearance.

It works particularly well alongside modern homes, grey aluminium pergolas, rendered walls and contemporary garden furniture.

There isn't necessarily a right or wrong answer — much depends on the property and garden design.

That's one reason we've chosen a different approach for our own decking.

One board. Two colours.

Our PergoLIFE 2.4m dual-colour composite decking board features two different finishes on the same board.

One face features our warm Natural Oak finish.

Flip the board over and the reverse features our contemporary Stone Grey finish.

That means you don't have to commit to the colour when ordering your decking.

Simply choose which side you want facing upwards during installation.

The two colours can also open up interesting possibilities for contrasting borders and different areas within a larger decking design.

What length composite decking should I buy?

Composite decking is available in several lengths.

Longer isn't automatically better.

Long boards can reduce the number of joins required on certain installations, but they can also be more difficult to transport, store and handle.

Shorter boards can be particularly convenient for typical domestic gardens and DIY installations.

PergoLIFE's initial composite decking boards are supplied in 2.4m lengths, providing a manageable board size for transportation and installation.

The best length ultimately depends upon the dimensions and layout of your deck.

How much composite decking do I need?

Start by calculating the area of your proposed deck.

For a rectangular area:

Length × Width = Deck Area

For example:

A 4m × 3m deck has an area of:

4m × 3m = 12m²

The actual number of boards required will then depend on the width of the decking board, spacing between boards, orientation and your intended layout.

You should also allow additional material for cuts and wastage.

We'll shortly publish a dedicated How Much Composite Decking Do I Need? guide with example calculations for common UK decking sizes.

Does composite decking require maintenance?

Composite decking is low maintenance, but that doesn't mean no maintenance.

Leaves, dirt and other debris should be removed periodically.

Occasional cleaning can help prevent dirt and organic material accumulating on the surface.

Particular attention should be paid to shaded or damp areas where algae and other organic growth can develop.

The advantage over timber is that routine painting, staining and sealing isn't normally required.

Is composite decking slippery?

Any outdoor surface can become slippery when contaminated with water, algae, leaves or other organic material.

Composite decking should therefore be kept clean and installed with appropriate drainage.

Woodgrain textures can also provide additional surface texture, although you should always look for independently tested slip-resistance figures if a manufacturer makes a specific anti-slip performance claim.

Is composite decking suitable for UK weather?

Composite decking is particularly well suited to outdoor applications where homeowners want to reduce the maintenance associated with natural timber.

However, the performance of the finished deck isn't determined by the decking board alone.

Correct installation is extremely important.

Suitable drainage, ventilation, board spacing and an appropriately constructed subframe all contribute to a successful installation.

This is particularly relevant in the UK's wet climate.

Can composite decking go under a pergola?

Absolutely.

In fact, composite decking and aluminium pergolas complement each other particularly well.

Decking helps define the floor of an outdoor living area while a pergola creates the structure above it.

Together they can create a dedicated space for:

• Outdoor dining
• Garden furniture
• Entertaining
• Outdoor kitchens
• Lounging
• BBQ areas

Composite decking is also a particularly attractive choice beneath a low-maintenance aluminium pergola because both products are designed to reduce the ongoing maintenance associated with traditional timber alternatives.

Can you install a pergola onto composite decking?

This requires some planning.

A pergola shouldn't normally be secured solely to the composite decking boards.

The pergola needs to be anchored securely to an appropriate structural base beneath the decking.

If you're building a new deck specifically for a pergola, we recommend determining the location of the pergola legs before constructing the decking subframe.

Suitable structural fixing points can then be incorporated into the design.

This is considerably easier than trying to modify a completed deck afterwards.

Which composite decking is right for me?

Consider five things:

1. Budget

Decide whether you're looking for an affordable alternative to timber or a premium capped composite product.

2. Appearance

Look closely at the surface texture and woodgrain rather than choosing purely from a small colour sample.

3. Board construction

Understand whether you're purchasing hollow or solid boards and make sure they're appropriate for the intended application.

4. Installation system

Consider the subframe, fixings, board spacing and trims required to complete the installation — not just the price of the decking boards.

5. The complete outdoor space

Think about how the decking will work with your house, garden furniture, fencing and pergola.

The best decking isn't necessarily the board viewed in isolation. It's the one that helps create the finished outdoor space you want.

Discover PergoLIFE Composite Decking

Our new 2.4m dual-colour composite decking has been selected specifically for contemporary UK outdoor living spaces.

Each board combines a realistic woodgrain appearance with the convenience of two colour choices:

Natural Oak for a warm, natural appearance.

Stone Grey for a contemporary architectural finish.

And because they're opposite faces of the same board, you can make the final colour decision when the decking is installed.

Two colours. One board. Your choice.