Choosing the Right Wood for Outdoor Furniture — Oak, Larch, Douglas Fir and More

Wood is not a uniform material. Two pieces of timber sitting side by side in a yard might look similar but behave completely differently once they're outside and exposed to a Welsh winter. Choosing the right species for outdoor furniture isn't just about looks — it determines how long a piece lasts, how much maintenance it needs, and whether it will still be standing in twenty years or quietly rotting in ten.

Here's how we think about wood species when we're building outdoor furniture, and what we'd tell anyone choosing a piece for their garden or woodland.

Why Species Matters for Outdoor Use

All timber is subject to the same enemies outdoors: moisture, UV light, and biological attack from fungi and insects. Different species resist these to very different degrees, and the resistance isn't about density alone — it's about the natural extractives in the heartwood.

The outer sapwood of virtually any tree is susceptible to decay. It's the dense, resin- or tannin-rich heartwood that determines a species' outdoor durability. Oak's high tannin content makes it naturally resistant to fungal attack. Larch's natural oils do the same job. These properties exist whether or not you apply any finish — they're baked into the wood itself.

The other factor is movement. Timber expands and contracts as it absorbs and releases moisture. Species with tight, stable grain move less, which means joints stay tighter and surfaces stay flatter. This matters enormously in joinery-heavy pieces like benches and tables.

Oak: The Gold Standard

Oak is the wood most people picture when they think of durable outdoor furniture, and the reputation is well deserved. European oak (Quercus robur, the species you'll find in British woodlands) is exceptionally durable outdoors without any treatment. Left unfinished, it weathers to a beautiful silver-grey over a couple of years. The surface develops a natural patina that many people find more attractive than the original colour.

Oak's tannin content makes it naturally resistant to both fungal decay and insect attack. A well-made oak bench, properly jointed and kept off the ground, will last decades — often outlasting the garden it sits in. Oak also hardens with age; old oak is genuinely tougher than new oak.

The downsides are weight and cost. A solid oak garden bench is a substantial object — it won't blow over in the wind, but you won't move it easily either. Oak is also among the more expensive timber options, which reflects its slow growth and high demand.

One thing to know about green (freshly milled) oak: it will check (develop surface cracks) as it dries. This is completely normal and doesn't affect structural integrity, but it's worth knowing if you're expecting a pristine surface. Kiln-dried oak moves less but costs more and has less of the character of green-cut timber.

Larch: The Unsung Hero

Larch doesn't get the recognition it deserves. It's a naturally oily softwood that weathers exceptionally well outdoors, is significantly lighter than oak, and costs considerably less. In many outdoor applications — cladding, decking, garden structures — larch outperforms species that cost twice as much.

European larch (Larix decidua) and Japanese larch (Larix kaempferi) are both grown in Britain, including extensively in Wales, which means it's often available as locally sourced timber. The natural resin content makes it resistant to decay and gives it a satisfying weight and solidity that most softwoods lack.

Left unfinished, larch weathers to a pleasant silver-grey, similar to oak. It can also be oiled to maintain its warm golden-amber colour. The grain is straight and relatively consistent, which makes it well-behaved in joinery.

The main limitation is that larch is softer than oak and will show dents and surface wear more readily. For a garden bench that sees hard daily use, that may matter. For a piece in a more sheltered position, or where weathered character is part of the appeal, it's an excellent choice.

Douglas Fir: Strong and Structural

Douglas fir isn't native to Britain but is widely grown here and is an excellent structural timber. It's strong for its weight, takes a finish well, and is more durable outdoors than most softwoods — though less so than larch or oak in long-term exposure.

Where Douglas fir excels is in structural applications: the legs and frames of heavy benches, the posts of garden structures, or any application where you need predictable strength in a straight, clean-grained timber. It machines and joints well, and its consistent grain makes it reliable for precise joinery.

For purely decorative or surface-exposed applications in a very wet climate, we'd lean towards larch or oak. But for a piece that combines structure with aesthetics, Douglas fir earns its place.

Pine: Not for Outdoors (Without Help)

Scots pine and other softwood pines are widely used in construction and interior furniture, but they are not naturally durable outdoors. Untreated pine will begin to decay within a few years of outdoor exposure — sooner in a wet climate like ours.

Pressure-treated pine (tanalised timber) is a different matter — the preservative treatment makes it serviceable for structures like decking frames, fence posts, and raised beds. But it's not a furniture timber, and the treatment process doesn't make it suitable for situations where aesthetics matter.

If someone is selling you "pine garden furniture" as a premium outdoor product without treatment, be sceptical. It will need regular maintenance or it won't last.

Finishing — Oil, Wax, or Leave It Natural?

For durable hardwoods like oak and larch, the honest answer is that you don't have to do anything. Both species will weather to a pleasing silver-grey and remain structurally sound for many years without treatment. Many of our customers prefer this — it's genuinely low-maintenance.

If you want to maintain the original warm colour, a penetrating oil (linseed oil, Danish oil, or a specialist outdoor wood oil) applied once a year does the job. Avoid film-forming finishes like varnish or paint on furniture that will flex seasonally — they crack and peel, which looks worse than bare weathered wood.

Wax can be used for tactile surfaces like tabletops, but it requires more frequent reapplication outdoors and offers less protection than oil. It's better suited to pieces kept under cover.

How We Choose Wood at Free Range Designs

When we're specifying a piece, we start with the intended use and location. A memorial bench for an exposed hillside gets oak — it will outlast anything else and age beautifully. A garden table for a sheltered courtyard might be larch or Douglas fir, balancing cost against performance. A structural element that won't be seen might be treated softwood.

We also prioritise sourcing locally. Welsh and British-grown timber is our default wherever it's available in the right species and grade. Shorter supply chains, lower carbon footprint, and the ability to trace the origin of the wood back to a specific woodland matters to us.

If you're looking at our outdoor furniture collection and have questions about species or finish for a specific situation, we're happy to talk it through — just get in touch. We build each piece to order, and getting the material right from the start is the most important thing we can do.