Iroko

Iroko

If you want a hardwood that will sit outside for decades with no treatment and no fuss, iroko is the one to reach for. Iroko (Milicia excelsa) is durability class 1 to 2, the highest rating we stock, and it is naturally oily enough to shrug off wet Irish winters in the ground, on a bench or in an external door frame. That is why it has been the default choice here for gates, garden furniture, external joinery and boat fit outs for generations. Imported from West Africa and stocked in our yard for delivery across Ireland in thicknesses from 26 to 100 mm, air dried, with FSC and PEFC certified supply available on request. Sold by the cubic foot and priced on enquiry.

Why Iroko?

People reach for iroko as the affordable answer to teak, and the comparison holds up better than most substitutions do. It has similar natural oil content, similar dimensional stability, and a golden brown colour that deepens to a rich mid brown after a few months of daylight. It is stable enough for wide external doors, hard enough for a workbench top, and it takes a fine finish off the machine.

Two things to plan for. Iroko has interlocked grain, meaning the fibres alternate direction through the thickness, which is what gives quarter sawn faces their ribbon stripe but also means it can tear out when planed against the grain and can split if you force a fixing into it. And it sometimes carries stone deposits in the fibre, hard calcium inclusions that will take the edge straight off a plane iron or a saw tooth. They are uncommon and visible once you know to look, but check a board before you machine it.

Installation guidance

Nothing here is difficult, but a little care pays. Pre drill and countersink every fixing rather than driving straight in, and back off the feed rate when machining across interlocked grain to avoid tear out. A sharp cutter and a light final pass will give you a surface that barely needs sanding.

The natural oils that make iroko durable also interfere with gluing and finishing. Wipe joint faces with acetone or methylated spirits immediately before gluing, and use a polyurethane or resorcinol adhesive rather than PVA on anything external. Use stainless steel fixings, A4 grade 316 where it gets wet, because iroko is high in tannin and will stain black around iron. Wear a mask when machining: the dust is a known irritant and gets to people who have handled it happily for years.

Finishing & maintenance

You have two routes and neither is wrong. Leave iroko bare and it fades from golden brown to a soft silver grey over roughly twelve months, which many people prefer on garden furniture and which asks nothing of you at all. Or oil it once or twice a year and hold that deep honey colour indefinitely. Most of our customers oil a front door and let a bench silver, which is a sensible split.

Whatever you do, do not use film forming finishes on external iroko. Yacht varnish and gloss paint cannot cope with the natural oil in the timber, so they lift, craze and trap moisture behind the film. A penetrating exterior oil is the right product and we stock the ones that work on oily tropical hardwoods, so ask us which to pair with yours. For both routes, wash occasionally with warm soapy water and a soft brush to lift grime and keep the grain sharp.