The Wood Guide
Wood species100 Wood species →

Our wood species

Wood groups

European hardwoods

Softwoods

Tropical hardwoods

Treated wood

Sheet materials

Construction timber

Other materials

Comparisons

Which wood for what

Understanding wood17 Understanding wood →

Properties and movement

Calculations and sizes

Pests and decay

Identifying, quality and trade

Wood in our world

Care & finishing28 Care & finishing →

The complete guide

Treating and finishing

By wood species

By furniture and place

Problems and repair

Seasons

Choosing & buying16 Choosing & buying →

Picnic tables

Beer tables

Garden benches

Garden furniture

Garden and atmosphere

Indoors

Build it yourself51 Build it yourself →

In the garden

In and around the house

Making furniture

Techniques

Tools and glue

Getting started

Trees & forests31 Trees & forests →

Tree portraits

Forests

From forest to plank

To the Wood Guide home page →

What is bankirai wood?

The Wood Guide · The wood register

Tropical hardwood · reference

Bangkirai

Also called bangkirai or yellow balau. Heavy, golden brown and naturally so durable that it lasts more than 25 years — even in the ground.

  • Shorea laevis · Shorea glauca
  • 850–1,100 kg/m³ — very heavy
  • Durability class 1
Shorea spp.
Home-made octagonal folding table and chairs in bangkirai (Shorea laevis)
Home-made octagonal folding table and chairs in bangkiraiShorea laevis
Magnified end grain of Shorea, the genus bangkirai belongs to (Shorea)
Magnified end grain of Shorea, the genus bangkirai belongs toShorea
Summary

Bankirai in brief

A tropical hardwood from the rainforests of South-East Asia, from trees of the genus Shorea. For decades the classic choice for decking — and not without reason.

What makes bankirai special is the combination of weight and durability. At 850 to 1,100 kg per cubic metre, it is one of the heaviest species you will find in a garden — heavier than oak, even heavier than teak. That density translates directly into resistance to weather, insects and wear.

It reaches durability class 1: more than 25 years, even in ground contact. That puts it in the same class as teak.

Botanical
Shorea laevis (Indonesia), Shorea glauca (Malaysia)
Heartwood
golden brown to dark brown, sometimes reddish
Sapwood
paler and clearly distinguishable
Density
850–1,100 kg/m³
Outdoors
class 1 — 25+ years, even in the ground
Maintenance
none; weathers to silver grey

To be fair: fresh bankirai leaches tannins that leave brown streaks on light paving, and it can splinter. Both are temporary or fixable, but you need to know about them.

In pictures · bankirai on the deck1 / 8
A trade name

Three spellings, one wood

Bankirai, bangkirai and yellow balau are the same tropical hardwood, from trees of the genus Shorea in the rainforests of South-East Asia. From Indonesia the species is Shorea laevis, from Malaysia Shorea glauca.

Click a chapter or use the arrows · years and seasons speeded up, streaks and splinters enlarged.

Origin

From the rainforests of South-East Asia

'Bankirai' is a trade name that covers two closely related species, depending on the country of origin.

Country of origin Botanical name
Indonesia Shorea laevis
Malaysia Shorea glauca
Ask where it comes from

As a tropical hardwood from primary rainforest, forestry practice is a real concern here. Ask your supplier where the wood comes from and how the forest is managed. If you are looking for a European alternative with comparable performance, look at robinia — class 1–2, with a rotation of 20 to 30 years, grown close to home.

How to recognise it

Colour

Golden brown to dark brown heartwood, sometimes with a reddish tint. The sapwood is clearly paler and easy to tell apart.

Texture

Fine to moderately coarse, with a strikingly even structure.

Grain

Straight to interlocked — the interlocked grain makes planing a little harder, but also gives the wood its toughness.

Weight

Lift a board and you know at once: this is one of the heaviest species on the market.

Measurable

Technical properties

Property Value What that means
Density 850–1,100 kg/m³ Very heavy — heavier than oak and teak
Durability class Class 1 More than 25 years, even in ground contact
Radial shrinkage ±0.5% Limited
Resistance High against weather and insects Needs no treatment to survive
Ageing Weathers to silver grey A surface process; the core stays intact

That weight has a practical downside: bankirai decking needs a sturdy substructure, and you won’t move loose pieces on your own in a hurry. More on how those classes work is in our hardwood guide.

Uses

What bankirai is used for

Decking and boardwalks

The classic use, and probably why you are here. See also wood for your decking.

Jetties and bank revetments

Class 1 means it holds up even in permanently damp conditions.

Garden structures

Posts, fencing and heavy outdoor structures — where the weight is actually an advantage.

Outdoor furniture

Possible, but heavy. For furniture you move around often, something lighter is a better choice.

What nobody tells you

Two things to know

Bankirai is excellent wood, but it has two quirks that catch people out.

Tannins

The brown streaks

In the first months, fresh bankirai leaches tannins. That leaves brown streaks on everything below it: light paving, white walls, a freshly poured patio. It usually disappears by itself, but on a light surface you can help it along by rinsing after rain for the first few weeks.

Splinters

Not as smooth as ipé

Bankirai is hard but less dense than ipé, and the interlocked grain can lift. If you walk barefoot on your decking, choose a smooth board or give it a light sanding along the grain after the first season.

Maintenance: let it grey or oil it

For durability, you don’t need to do anything; the wood then weathers to silver grey. If you want to keep the golden brown, oil it every year with a wood oil in the right colour. Half measures don’t work: decking you oil once and then forget looks blotchy.

Quick answer

Frequently asked questions about bankirai

How long does bankirai last?

Durability class 1: more than 25 years, even in ground contact. That puts it in the same class as teak.

Why are there brown streaks on my paving?

They come from tannins that fresh bankirai leaches in the first months. They usually disappear by themselves; on light paving you can help by rinsing after rain until the tannins have washed out.

Does bankirai splinter?

It can. Bankirai is hard but not as dense as ipé; on decking where people walk barefoot, a smooth board or a light sanding after the first season is well worth it.

Is bankirai the same as bangkirai?

Yes. Bankirai, bangkirai and yellow balau all refer to the same tropical hardwood from trees of the genus Shorea. The spelling varies by supplier.

Do you sell bankirai?

No. Our furniture is made of pressure-treated spruce, Douglas fir, teak and other hardwood. Bankirai is in our register because it is the most asked-about wood for decking — and because those tannin streaks surprise people all over again every spring.

More in The Wood Guide

Bankirai in perspective

Bankirai is a reference species in our register — wood we don’t use, but do know well.

To The Wood Guide Wood for your decking What is hardwood?

Have a question about your project? Just ask — we're happy to help.

Photos via Wikimedia Commons: Shorea laevis — No machine-readable author provided. Kinou~commonswiki assumed (based on copyright claims)., CC BY 2.5 · Shorea — G-Lignum, CC BY 4.0

The Wood Guide

More in Wood species

Other sections:Understanding woodCare & finishingChoosing & buyingBuild it yourselfTrees & forests