Handling & safety. Iroko dust is a known sensitiser — some people react on first contact, others after repeated exposure, so the risk grows rather than shrinks. Extraction or good ventilation, an FFP3 mask when machining, and wash hands after handling.
Suitable uses
Exterior joinery, cladding, decking, garden furniture, window frames, doors, marine and boat fit-out.
Properties
| Latin name | Milicia excelsa |
|---|---|
| Species type | Hardwood |
| Origin | West and Central Africa — the traditional teak substitute for exterior joinery and boat work. |
| Density | 660 kg/m³ |
| Janka hardness | 5,310 N |
| Modulus of rupture | 97.1 MPa |
| Elastic modulus | 10.9 GPa |
| Crushing strength | 53.5 MPa |
| Specific gravity | 0.66 |
| Porosity | Semi-ring-porous |
| Movement class | Low |
| Tangential movement | 4.8% per 1% MC |
| Radial movement | 3.3% per 1% MC |
| Volumetric shrinkage | 8.8% |
| T/R ratio | 1.5 |
| Durability (EN 350) | Class 2 |
| Relative cost | Premium |
Typical values at around 12% moisture content. Individual boards vary.
Iroko dust is a known sensitiser. Some people react on first contact; others develop a reaction after repeated exposure — so the risk grows with how much you work with it, rather than shrinking.
- Extraction, or good ventilation. Don’t cut, plane, rout or sand iroko in a closed space without one or the other. This matters more than anything else here.
- FFP3 mask for cutting, sanding and machining. A basic dust mask isn’t adequate for this timber.
- Wash hands after handling — particularly before eating or drinking.
If you’ve reacted before, don’t assume it’ll be milder next time. Sensitisation typically gets worse with repeat exposure, not better.
Iroko is what you reach for when a job needs teak-grade durability without teak prices. It’s a dense, durable African hardwood that handles weather properly, and it’s been the standard substitute for teak in marine, exterior joinery and landscaping work for decades.
It has real exterior credentials. Left untreated outdoors it holds up, greys to a soft silver the way teak does, and takes oil or stain readily if you’d rather hold a colour. For window frames, doors, garden furniture, decking and boat fit-out, it’s a well-proven choice.
Where it differs from teak
Mostly in movement and behaviour.
Iroko is a little more dimensionally active than teak, and its grain is often interlocked — so there’s tearout risk when planing, and the surface doesn’t come up quite as cleanly.
It also contains deposits that blunt tooling faster than average. Keep your edges sharp and expect to touch them up more often.
Two practical things that catch people out
It corrodes steel fixings. In damp conditions, iroko reacts with standard steel the same way oak and chestnut do. Use stainless fixings for exterior work. Rust streaks down a cladding board or a failed fixing five years on both trace back to this.
“African teak” is a marketing phrase, not a botanical one. Iroko is Milicia excelsa. If a job specifies African teak and expects teak’s exact behaviour, it’s worth clarifying what’s actually being offered — the two are similar in service, and not identical.
Colour
Golden to reddish-brown when fresh, darkening with exposure. Variable board to board — not dramatically, but enough that matching visible components is worth planning at the outset rather than hoping for the best.
Working the timber
Generally easy to work though interlocked grain can tearout on machine planing — light cuts help. Its natural oiliness means keep blades clean and consider wiping surfaces before finishing. EN 350 classes iroko durable (class 2), with some classifications putting it at very durable.
Finishing & gluing
Naturally oily, so it weathers beautifully with no treatment and resists the elements; if coating, degrease the surface first so film finishes key in. Watch for yellow deposits (calcium carbonate) that can dull cutters.
The oiliness that makes it weatherproof works against glue — fresh-machined, dust-free surfaces and a quality epoxy or PU give the most reliable joints.