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What is kempas?

The Wood Guide · The wood register

Tropical hardwood · reference

Kempas

Warm orange to reddish brown, very hard and surprisingly strong. Popular for indoor floors and stairs — and with one limitation you need to know about.

  • Koompassia malaccensis
  • 40 to 60 m tall
  • Excellent indoors, treated outdoors
Koompassia malaccensis
Solid kempas board in warm orange to reddish brown (Koompassia malaccensis)
Solid kempas board in warm orange to reddish brownKoompassia malaccensis
In pictures · Kempas1 / 7
Chapter 1 · The species

Kempas

Warm orange to reddish brown, very hard and surprisingly strong. Popular for indoor floors and stairs — and with one limitation you need to know about.

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Summary

Kempas in brief

The wood of Koompassia malaccensis, an imposing broadleaf tree from the tropical rainforests of Malaysia, Indonesia and Thailand.

The tree reaches forty to sixty metres, with a straight trunk one to one and a half metres in diameter. The wood it yields is warm orange to reddish brown, with a high density and a strength that makes it suitable for heavily loaded indoor uses.

Indoors, kempas is excellent: hard-wearing enough for stairs and heavily used floors, with a warm colour that sets it apart from the browner tropical species. Outdoors it is a different story — there it needs a protective treatment.

The honey tree

In Southeast Asia, Koompassia trees are known as nesting trees for giant honey bees. Local honey hunters climb them, and in parts of Malaysia the trees are therefore spared during felling — the wood is worth less than the honey the tree produces every year.

Botanical
Koompassia malaccensis
Origin
Malaysia, Indonesia, Thailand
Height
40 to 60 metres
Trunk diameter
1 to 1.5 metres
Colour
warm orange to reddish brown
Strength in
hardness and wear resistance

To be fair: kempas is not inherently durable outdoors and needs treatment. It also reacts strongly with iron — black stains around every ordinary screw — and it moves more than many other tropical hardwoods. For outdoor work there are better choices.

Measurable

What characterises kempas

High density

Heavy and hard, with the wear resistance a staircase or heavily used floor demands.

Warm colour

Orange to reddish brown, distinctly warmer than most tropical flooring species.

High strength

Good bending and compressive strength, also suitable for structural indoor uses.

Reacts with iron

Tannins cause black stains around ordinary steel. Stainless steel is a must.

Uses

What kempas is used for

Use Suitable? What to look for
Indoor floors Excellent The main use; very hard-wearing
Stairs Excellent Hard enough for intensive use
Indoor structures Good High strength
Outdoor work Limited Needs treatment; other species are more suitable
Furniture Good Heavy; pre-drilling is a must
Ground contact Not recommended Choose azobé, bilinga or robinia
Outdoors, better choose something else

If you want decking or cladding, you are better off with ipé, cumaru or bankirai. Kempas earns its place indoors.

Quick answer

Frequently asked questions about kempas

Can kempas be used outdoors?

Only when treated, and even then there are better choices. Kempas is an indoor wood — for outdoors, choose ipé, cumaru or bankirai.

Why are black stains appearing around my screws?

Because of the reaction between the tannins in kempas and the iron in ordinary steel. Use stainless steel fixings; existing stains are permanent.

What is kempas best suited for?

Indoor floors and stairs. It is hard, hard-wearing and warm in colour — exactly what a heavily used floor demands.

How big does a kempas tree grow?

Forty to sixty metres, with a straight trunk one to one and a half metres in diameter.

More in The Wood Guide

Kempas in perspective

An excellent indoor wood, but not the first choice outdoors.

To The Wood Guide Tropical hardwood Cumaru

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

Photo via Wikimedia Commons: Koompassia malaccensis — Vitanes, CC BY-SA 4.0

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