Species data
Iroko
Milicia excelsa - a hardwood from tropical Africa. Also sold as african teak.
Properties at a glance
| Janka hardness | 1,190 lbf |
| Stiffness (MOE) | 1,580,000 psi |
| Specific gravity | 0.66 |
| Density | 41.2 lb/ft3 (660 kg/m3) |
| Weight per board foot | 3.43 lb |
| Shrinkage, green to oven-dry | 4.8% tangential / 3.3% radial |
| Indicative price | $14.00 per board foot (estimated) |
Values are at about 12% moisture content. Density is specific gravity times 62.4; a board foot is one twelfth of a cubic foot, so weight per board foot is that density divided by twelve. Anything marked estimated is our own figure, not a measured one.
How Iroko compares
Measured against the 113 solid woods in this database: it is harder than 56% of them, heavier than 55%, and stiffer than 42%.
What that means in the shop
A 4/4 board 8 inches wide and 8 feet long is 5.33 board feet, so in Iroko it weighs about 18.3 lb. A stack of ten is 183 lb - worth knowing before you load a rack or a car.
Against red oak, the trade's usual yardstick at 1,220 lbf, Iroko is about 98% as hard and 94% as heavy.
Its shrinkage is 4.8% tangential against 3.3% radial, a ratio of 1.5 to 1. The wider that ratio, the more unevenly a flatsawn board moves across its width as humidity changes, and the more it wants to cup; anything near or above 2 to 1 is worth quartersawing or restraining for panels and wide tops. This one moves comparatively evenly.
Woods of similar hardness
Closest to Iroko on hardness in this database: Makore (1,200 lbf), Koa (1,170 lbf), Oregon Ash (1,160 lbf), Red Oak (1,220 lbf). Similar hardness does not mean similar behaviour - check density and movement before substituting one for another.
Working with it
Workability. Generally cooperative; interlocked grain may tear; finishes and glues well
Durability. Very durable; fends off insects and rot alike
Typical uses. boatbuilding, flooring, furniture, cabinetry, veneer, turning.
Related calculators
Sources
MOE, SG (12% MC), Janka and shrinkage from The Wood Database (cites USDA FPL Wood Handbook). CT/CR omitted: iroko is not listed in the FPL/Hoadley dimensional change coefficient table. Uses, region, durability and workability summarized from The Wood Database. Price indicative.
These calculators are for planning and estimation. Engineering results (shelf sag, wood movement) use published average material properties; real boards vary by grade, grain, moisture and defects. Verify load-bearing designs with a professional.