If you're planning a new outdoor space in Ireland, composite decking boards deserve serious consideration. This guide covers everything from colour selection and board profiles to subframe options and installation essentials, so you can make a confident, informed purchase.

Key Takeaways

Composite decking is a manufactured board made from recycled wood fibres and high-density polyethylene (HDPE). We stock 14 products in the Double L composite decking collection, available in a wide range of colours and profiles.

Our decking boards - available in a range of colours including silver-grey, desert sand, stone grey, mocha brown, charcoal and black - are low maintenance, fade-resistant and engineered for Irish weather conditions.

A complete system is available from one source: composite cladding, bullnosed end boards, composite decking fittings and aluminium joists for decking, covering everything from structure to finishing details.

Below you'll find guidance on how to choose the right colour and profile, how to calculate how many boards you need, and how to install them correctly so they last decades.

What Is Composite Decking and Why It's Ideal for Irish Gardens

Composite decking is a board manufactured from a blend of recycled wood fibres and thermoplastics, typically HDPE. Most quality composite decking contains 60% recycled wood materials and around 30% recycled high density polyethylene, with the remainder being UV stabilisers, pigments and binding agents. The result is a board that looks and feels like natural wood, but is more durable and handles moisture, frost and heavy foot traffic far better than traditional softwood or hardwood alternatives.

Up until recently, most Irish patios relied on pressure-treated pine or imported hardwoods. These materials have well-known drawbacks in a wet maritime climate: they absorb water, warp, crack, develop mould, and demand regular staining or oiling to stay presentable. Composite decking is resistant to splintering and cracking, which removes those recurring headaches. The surface is slip-resistant and safe for barefoot use - a genuine advantage on a rain-soaked Friday evening. The boards are also produced to BS standard 7976 part II for slip resistance, which matters when algae and wet leaves are part of daily life.

Double L offers 14 products in its composite decking collection, all designed around 2200mm deck boards with matching bullnosed end boards and fittings. Key benefits include:

• Low maintenance - no annual staining, oiling or painting required, and no need to keep boards painted or sealed in normal use

• Environmentally friendly - composite decking boards are 100% recyclable at the end of their life, and the recycled content diverts waste from landfill

• Long service life - with a lifespan exceeding 20 years under proper care, these boards reduce the cycle of replacement that makes timber decking expensive over time

Because composite decking requires fewer chemical treatments than timber and lasts significantly longer, its full lifecycle environmental impact is notably lower. That's a meaningful step toward sustainability without compromising the beauty of your outdoor space.

Our Composite Decking Collection at Double L

This section showcases the Double L composite decking collection. You can view and buy every product at https://doublel.ie/collections/composite-decking.

The collection currently contains 14 products, covering different colours, surface textures and profiles. All boards are compatible with our fittings and subframe options, so you can mix and match with confidence. Here's what's available across the colour groups, which include gray 6 products, brown 4 products, black 3 products, green 2 products and bronze 1 products:

• A cool, contemporary silver-grey tone that pairs perfectly with grey window frames and modern paving - one of our most popular choices for urban gardens.

• A warm beige-sand desert tone that works beautifully with south-facing patios and light render, bringing warmth without overpowering surrounding planting.

• A weathered, antique-style finish that delivers a heritage feel for period properties.

• A classic golden-brown teak-effect tone.

• A mid-tone stone grey effect, versatile for both rural and urban gardens, sitting comfortably alongside gravel paths and natural stone walls.

• A rich mocha brown timber-effect board, ideal for traditional homes and cottages.

• A deep charcoal grey tone for architectural, modern schemes and commercial terraces, striking alongside glass balustrades.

• A bold, dramatic black board suited to feature areas and hospitality spaces.

Pricing varies across the collection depending on board profile, colour and fittings selected - please get in touch for current pricing on individual products. Most boards are 2200mm long, and our bullnosed end boards are designed to match this for cleaner detailing and reduced cutting waste.

Board Sizes, Profiles and Matching End Boards

Most decking boards in our range measure around 135–150mm wide and approximately 23–25mm thick, at a standard length of 2200mm. This 2.2m length is easy to handle and manoeuvre on site, though longer runs will require butt joints at board ends - always plan for a double joist at each joint to keep things solid. For context, some wider profile boards exist in the industry - Pebble Grey Wide decking, for instance, has a profile of 210mm x 23mm - but the 135–150mm range remains the sweet spot for residential use in Ireland. Marina composite decking is designed for large scale areas where wider boards and fewer joints are preferred, though our standard residential dimensions cover the vast majority of garden projects.

Our boards feature reversible surfaces. Montana composite decking offers reversible smooth and grooved surfaces, and the same principle applies across our collection: one side typically presents a deep woodgrain emboss, while the other offers a brushed or lightly grooved texture. This gives you flexibility to choose the finish that feels right underfoot.

When it comes to core construction, hollow composite boards are lightweight and generally cheaper than solid boards, making them a good choice for budget-conscious projects. Solid composite boards handle immense weight and feel more like traditional wood, so they're preferred for high-traffic areas and commercial installations. Uncapped composite decking lacks an outer protective shell and is more porous, which means it can absorb stains and fade faster. Capped composite decking features a protective polymer shell for enhanced durability - all Double L boards use a capped construction for this reason.

Edge profiles also matter. Grooved edge boards work with hidden fastening systems for a clean appearance, which is how most of our field boards are designed. Square edge boards feature straight sides for traditional screw usage, useful for fascia and perimeter boards. Our bullnosed end boards are colour-matched to key finishes such as silver-grey, desert sand, mocha brown and charcoal for a seamless finish. Ever-Deck composite decking is available in three standard colors as another industry reference point, but our 14 products collection provides far broader choice.

Subframe Options: Timber vs Aluminium Joists

The performance of composite decking depends heavily on the subframe. Your boards need to be properly supported, and choosing between treated timber joists and aluminium joists is one of the most important decisions you'll make.

Traditional treated timber subframes use C16 or C24 softwood joists, pressure-treated to Use Class 4 for exterior exposure. These are familiar to most Irish carpenters, widely available, and cost-effective for straightforward garden decks. The standard joist spacing for composite boards laid perpendicular is around 350mm centres (residential) or 300mm centres for heavy-use or commercial applications. Timber joists do have limitations, though: they can rot over time, warp if ventilation is poor, and attract insect damage in damp ground conditions.

Aluminium joists for decking solve all of those problems. They're completely rot-proof, dimensionally stable across temperature swings, lighter per unit span, and ideal for low-profile installations over existing patios or balconies. Our Double L composite decking collection is compatible with both aluminium joists and standard timber joists, and we supply appropriate composite decking fittings for either option. Composite joists batten systems are also available for specific applications.

When to choose aluminium:

• Roof terraces and balconies where weight matters

• High-moisture areas or poor drainage sites

• Over existing concrete slabs where low clearance limits ventilation

• Coastal or exposed locations where timber would degrade faster

When timber is acceptable:

• Simple garden decks with good airflow underneath

• Sites with at least 300mm clearance above soft ground

• Budget-focused projects with well-drained soil

Composite Decking Fittings and Installation Essentials

Correct fixings and fittings are essential to maintain warranty and long-term performance of your decking boards. Cutting corners on installation is the single most common reason composite decks underperform - so this section matters.

The main composite decking fittings supplied or recommended by Double L include:

• Starter clips for the first board against a wall or edge

• Hidden clips for main field boards (used with grooved edge profiles)

• Colour-matched screws for bullnosed end boards and fascia

• Spacers to ensure consistent expansion gaps

Here are the critical steps to install your deck correctly:

• Leave a 5mm expansion gap at board ends and 4–6mm between board sides. Composite expands and contracts with temperature, so these gaps are non-negotiable.

• Joists should be spaced no further than 16 inches apart (approximately 400mm) for perpendicular board layouts, and closer (around 250mm) for diagonal runs. Composite decking boards should be spaced 16 inches apart as a baseline maximum.

• Use a double joist where board ends meet for support. Every butt joint needs to land on a double joist to prevent bounce and ensure the boards are properly supported.

• Install composite decking boards with a slight fall for drainage - around 5mm per metre away from the house. This prevents water pooling and keeps the subframe dry.

• Allow boards to adjust to temperature for one day before installation. Stack them flat on-site, ideally on the subframe, so they acclimatise to local conditions.

• Ensure a free-draining base and ventilation under boards. A minimum clearance of 100mm above hard surfaces (or 300mm above soft ground) lets air circulate and prevents trapped moisture.

Full installation instructions are supplied with all products or downloadable from the Double L site. This section is a practical overview - not a replacement for the step-by-step guide that comes with your order.

Designing Your Deck: Colour, Direction and Layout

This is the enjoyable part. Think about how your new composite decking will connect your house, garden and existing hard landscaping into one coherent outdoor living space.

When choosing colour, consider what you're matching or contrasting against. Grey window frames and contemporary render look sharp alongside our silver-grey or charcoal composite decking. Red brick, timber cladding or stone walls pair naturally with our mocha brown or stone grey composite decking for a warmer, more natural feel. Darker boards like our black composite decking create drama but can feel hot underfoot in direct summer sun - something to factor in for south-facing patios.

Deck direction affects how a space feels. Running boards away from the house makes a garden feel longer. Running them across the width visually widens a narrow patio. All Double L boards are 2200mm, giving you flexibility to lay them either way - just plan for staggered joints on longer runs.

Feature borders and breaker boards are an easy way to add visual interest to larger decks. A popular approach is to frame a lighter field - say our desert sand composite decking - with a contrasting border in charcoal or black. This “picture frame” technique is simple to execute and transforms a flat rectangle into something that feels designed.

Mini-scenario: A 2026 semi-detached home in Dublin replaces a slippery, ten-year-old pine deck with our charcoal composite decking boards. Matching composite cladding wraps two planter boxes flanking the back door, and bullnosed end boards frame the steps down to the lawn. The entire project takes a weekend with two people - no green timber treatments, no staining, just a finished deck ready for that first barbecue.

Cost, Lifespan and Maintenance Compared to Timber

Composite decking has a higher upfront material cost than basic pressure-treated decking boards. In the UK and Irish market, installed composite typically costs roughly double what softwood costs per square metre. But upfront cost is only half the equation.

Composite decking is engineered for a long service life depending on product tier and installation quality. A well-installed capped composite deck - like the boards in our collection - will comfortably deliver decades of residential use. Softwood decks in Irish conditions often need major refurbishment or full replacement after 8–12 years. When you factor in the cost of annual staining, board replacements, and your own time, composite wins on lifetime value.

Composite decking requires no painting, staining, or sealing. The maintenance routine is refreshingly simple:

• Seasonal sweep and wash with mild detergent

• Occasional soft-brush scrub to remove algae or moss

• Regular cleaning prevents dirt and mold growth on composite decking

• No need to buy or apply oil, stain, or sealant - ever

Here's how timber and composite stack up over time:

• Initial material cost: Timber is lower; composite costs more upfront

• Yearly maintenance hours: Timber needs 4–8 hours of sanding, staining and inspection; composite needs 1–2 hours of washing

• Typical lifespan: Softwood 8–15 years; composite significantly longer

• Rot and decay risk: Timber is high without treatment; composite is virtually zero

• Splinter and crack risk: Timber is common; composite boards won't splinter or develop cracks under normal use

Our Double L composite decking collection is designed to keep colour and structural performance with minimal upkeep. Our lighter tones - such as silver-grey and desert sand in particular - are engineered for enhanced fade and stain resistance, making them an excellent choice for exposed or south-facing sites. Composite decking offers durability and low maintenance benefits over wood decking, and those benefits compound every single year you don't have to sand, stain or replace a rotten board.

It requires less maintenance than traditional timber decking - and that's the point. You buy a composite deck so you can use your garden, not spend every spring maintaining it.

FAQ – Composite Decking Boards

These FAQs address common questions not fully covered above and relate specifically to Double L's composite decking collection.

How many composite decking boards do I need for my patio?

The exact quantity depends on your patio size and layout, and our boards are supplied at 2200mm lengths. As a quick example: a 4.0m × 4.0m deck using boards at 150mm cover width would need roughly 27 boards to cover the width, with longer runs made up of 2200mm sections joined on double joists, plus bullnosed end boards for edge finishing. It's wise to order 5–10% extra to allow for cuts, waste and future repairs. You can contact Double L with your measurements and we'll calculate precise quantities for boards, composite decking fittings, end boards and aluminium joists - making the process easy and accurate.

Can I mix different composite decking colours in one project?

Absolutely. Mixing colours is common and visually effective. You might combine silver-grey with black as a picture frame border, or use mocha brown steps against a desert sand main deck. Keep to two or three colours maximum to avoid a busy look, and coordinate your bullnosed end boards and composite facia boards with the main field colour. View the full range online - all 14 products are designed to work together within the Double L composite decking collection.

Is composite decking from Double L suitable for coastal or exposed locations?

Our composite decking boards are designed to resist moisture, salt spray and UV exposure far better than standard timber, making them well-suited to coastal areas around Cork, Galway and Wexford. For very exposed or marine environments, we recommend using aluminium joists and stainless or coated composite decking fittings for maximum durability. Correct ventilation and drainage under the deck remain important even with composite materials - the boards handle the water, but the subframe needs airflow to perform for the longer term.

Can I install composite decking over an existing concrete patio?

This is one of the most common applications we see. Aluminium joists or treated timber joists are packed and levelled over the concrete, then composite decking boards are fixed on top using our recommended fittings. The important thing is to maintain a slight fall for drainage and avoid standing water between concrete and joists. Complex or low-clearance installations may benefit from advice by an experienced installer familiar with Double L products - feel free to contact us for guidance. Composite decking boards are 100% recyclable at the end of their life, so even decades from now, the materials won't go to waste. The environment benefits from every deck that stays out of landfill.

What warranty do you offer on your composite decking boards?

Double L composite decking boards are backed by a warranty of up to 20 years, covering structural integrity, resistance to rot, splitting and excessive fading under normal residential use. Warranty terms vary by product line - ensure you check the specific documentation for your chosen boards. Correct installation using approved composite decking fittings, end boards and, where specified, aluminium joists is a condition of maintaining full warranty protection. This is why following the joist spacing, expansion gap and ventilation guidelines we've outlined above isn't optional - it protects both your deck and your warranty.

Ready to create an outdoor space that lasts? Browse the full Double L composite decking collection to view all 14 products, compare colours, and find every fitting, end board and joist you need. If you have measurements or a project plan, contact us and we'll help you calculate exactly what to buy - down to the last clip.