Best Wood for a Pergola: Durable Hardwoods for Posts, Beams and Rafters

A pergola sits outside all year, in sun, rain, wind and frost. It has to carry its own weight, climbing plants, sometimes lights, shade sails or a roof, and it is often the centrepiece of a garden, terrace or restaurant patio. Choosing the best wood for pergola projects means finding timber that is naturally durable outdoors, strong enough for the spans you want, stable enough not to twist, and good-looking for many years.

In this guide we compare the African hardwoods that landscapers, garden builders and outdoor structure makers use most. At Global Timber Trade Hub we supply posts, beams and rafters in these species from Central Africa. We also cover sizes, spans, finishes, fixings and how to buy pergola timber in volume.

What makes a good pergola wood?

• Natural durability: heartwood that resists rot and insects without chemical treatment.
• Strength and stiffness: beams must span between posts without sagging.
• Stability: large sections should not twist, cup or crack badly as they weather.
• Availability in big sizes: long, straight, defect-free posts and beams.
• Appearance: colour, grain and the way the wood weathers.
• Workability: notches, joints and decorative ends must be cut cleanly.

Pergola woods at a glance

Prices are indicative starting points per cubic metre for sawn sections. Large, long, clear beams cost more than standard sizes.

Iroko: the go-to pergola timber

Iroko is often called African teak. It is durable outdoors, stable, available in large sections and easier to work than the very dense species. It weathers from golden brown to a soft silver-grey if left unfinished. For most garden and hospitality pergolas, iroko gives the best balance of cost, looks and life. Read more in iroko vs teak and iroko wood price.

Tali and okan: heavy-duty and great value

Tali and okan are dense, very durable hardwoods widely used for bridges, sleepers and heavy outdoor construction. They give a solid, substantial pergola that will last for decades, and they cost less per cubic metre than iroko. The trade-off is weight and harder working: pre-drill every fixing and use carbide tooling. They suit public spaces, parks and commercial projects. See our tali wood and okan wood guides.

Bilinga: bright and long-lasting

Bilinga has a striking golden-yellow colour that stands out in modern designs. It is very durable, widely used for marine piles and decking, and lighter than azobe. It can show some surface checking as it weathers, which is normal for large outdoor sections.

Afrormosia and doussie: premium pergolas

For high-end projects, afrormosia gives a fine, teak-like look with excellent stability, while doussie is one of the most stable and durable African hardwoods. Both are CITES-listed, so exports need permits and lead times are longer. They are popular for luxury villas, hotels and yacht clubs. See afrormosia vs teak and doussie wood.

What about sapele?

Sapele is beautiful and stable, but its durability outdoors is moderate. It can work for a sheltered pergola with a good finish and regular maintenance, but it is not our first choice for posts or for parts that stay wet. For long life with little care, choose iroko or one of the very durable species.

Typical pergola sizes

• Posts: 120 × 120 mm to 200 × 200 mm, 2.7–3.6 m long.
• Main beams: 70 × 200 mm to 100 × 250 mm, in lengths to span between posts.
• Rafters or cross beams: 45 × 145 mm to 70 × 195 mm, often at 400–600 mm spacing.
• Battens or slats: 30 × 50 mm to 45 × 70 mm for shade.

Larger sections look more substantial and can span further, but they also cost more and dry more slowly. Ask a structural engineer for spans on larger or roofed pergolas.

Spans and loads

Dense species such as tali and okan are stiffer than iroko, so the same beam size can span further. As a rough guide for a simple open pergola, a 100 × 200 mm iroko beam can usually span around 3 m between posts, and denser species a little more. If you plan to add a roof, glass, shade sails, heavy climbing plants or lights, the loads go up, and sizes must be checked by an engineer under local rules. Our hardwood beams guide covers sizing in more detail.

Post bases and foundations

Even durable species last longest when they stay dry at the base. Most designers fix pergola posts on galvanised or stainless steel shoes set in concrete, keeping the end grain 20–50 mm above the ground. This stops water wicking up the post and makes replacement easier. If posts must be set in the ground, use the most durable species, heartwood only, with gravel drainage.

Joints and fixings

• Notched joints: beams sit in notches cut into posts for strength and a clean look.
• Bolts: stainless steel or hot-dip galvanised coach bolts.
• Screws: stainless outdoor screws, always pre-drilled in dense woods.
• Avoid plain steel: tannins in some hardwoods react with iron and cause black stains.

Finishes and weathering

Left unfinished, all these woods weather to a silver-grey. Many people like this natural look, and it needs no maintenance. To keep the original colour, apply a UV-resistant oil or stain every one to two years. Avoid film-forming varnishes outdoors, as they crack and peel. Iroko and some other species can bleed extractives in the first months, which may stain paving below, so let new timber weather or wash surfaces regularly at first.

Moisture content and drying

Large sections such as 150 × 150 mm posts are slow to dry. They are usually supplied air dried or fresh sawn rather than fully kiln dried. Expect some small surface checks as they dry outdoors; this is normal and does not affect strength. Store timber flat, stickered and covered before building. See kiln dried vs air dried lumber.

Pergolas for hospitality and public spaces

Restaurants, hotels, holiday parks and councils build pergolas that must look good with little maintenance and take heavy use. Dense, durable species such as tali, okan and bilinga, with stainless fixings and steel post shoes, give long life with minimal care. For a warmer, refined look in a hotel garden, iroko or afrormosia are popular.

How much timber does a pergola need?

A typical garden pergola of 4 × 3 m, with four 150 × 150 mm posts, two main beams and eight rafters, uses about 0.4–0.6 m³ of timber. Larger commercial pergolas can use several cubic metres. Landscaping companies building many pergolas often buy a container of mixed posts, beams and rafters at once.

Buying pergola timber in volume

For repeated projects, set up a fixed list of sizes and lengths, choose one or two main species and order by the container. Mixing posts, beams, decking and cladding in one shipment spreads freight cost. Browse our heavy construction and marine timber and see timber shipping cost.

Design ideas

The timber you choose shapes the style of the pergola. Chunky 200 mm posts in tali or okan, with simple square-cut beams, give a strong, rustic look that suits parks, vineyards and large gardens. Slimmer iroko sections with shaped beam ends feel more traditional and work well in cottage gardens. For modern homes, many designers use flat-topped pergolas with closely spaced slats in bilinga or afrormosia, which create striped shade and a clean, architectural line. You can also mix materials: hardwood beams on powder-coated steel posts give a light, contemporary look and keep all the timber well above the ground.

Adding a roof or louvres

Some buyers turn a pergola into a covered outdoor room with polycarbonate, glass, metal sheets or adjustable louvres. A roof adds weight and wind load, so beams, posts and fixings must be sized by an engineer, and planning rules may apply. Dense, stiff species such as tali and okan are a good choice for roofed structures.

Common mistakes

• Posts set directly in wet soil: even durable posts last longer on steel shoes.
• Plain steel fixings: they rust and stain the wood black.
• Undersized beams: they sag, especially under plants or shade sails.
• Using moderately durable woods for posts: choose iroko or denser species.

Our honest advice

For most garden and hospitality pergolas, iroko gives the best mix of looks, stability, durability and workability. For heavy public structures, tali and okan offer more strength at a lower price per cubic metre. For premium designs, afrormosia and doussie are worth the extra cost and lead time. Keep post bases dry, use stainless fixings and size beams for the loads you plan.

Sources

• The Wood Database for durability and strength data.
• Pergola on Wikipedia

Related guides

• Best wood for outdoor furniture
• Hardwood cladding
• Best hardwood for decking
• Best wood for fence posts
• Ipe alternatives

Frequently asked questions about the best wood for pergola builds

What is the most durable wood for a pergola?

Very durable dense hardwoods such as tali, okan, bilinga and doussie, with iroko close behind.

Does a hardwood pergola need treatment?

No chemical treatment is needed for durable heartwood; oil only if you want to keep the colour.

What size posts does a pergola need?

Commonly 120–200 mm square, depending on height, spans and loads.

Is iroko good for pergolas?

Yes. It is durable, stable, available in large sections and easy to work.

Get a quote for pergola timber

Send us your species, section sizes, lengths and quantities through our quote form. We will reply with a firm price and shipping options.