WOOD SPECIES · Hardwood
Iroko: density, weight and properties
Milicia excelsa, Milicia regia
Iroko (Milicia excelsa) averages 640 kg/m³ at 12% moisture content, according to CIRAD’s Tropix database. The figures below are averages for clear, mature wood; individual boards vary with origin, growth and moisture.
Key figures
- Density at 12% moisture
- 640 kg/m³Average for mature wood; varies with origin and growth
- Monnin hardness at 12%
- 4.1French surface-hardness index; not convertible to Janka
- Bending strength (modulus of rupture)
- 87 MPa
- Stiffness (modulus of elasticity)
- 12,840 MPa
- Compression parallel to grain
- 54 MPa
- Tangential shrinkage, green to oven-dry
- 5.4%
- Radial shrinkage, green to oven-dry
- 3.5%
- Fibre saturation point
- 23%
Weight at 12% moisture content
Volume × 640 kg/m³, the same calculation as the weight calculator. Green or wet wood weighs considerably more.
| Piece | Size | Weight |
|---|---|---|
| 1 cubic metre | 1,000 × 1,000 × 1,000 mm | 640 kg |
| 1 board foot | 12 × 12 × 1 in | 1.51 kg |
| 1×4 board, 8 ft | 3/4 × 3 1/2 in actual × 8 ft | 2.64 kg |
| 1×6 board, 8 ft | 3/4 × 5 1/2 in actual × 8 ft | 4.15 kg |
| 2×4 board, 8 ft | 1 1/2 × 3 1/2 in actual × 8 ft | 5.29 kg |
| 2×6 board, 10 ft | 1 1/2 × 5 1/2 in actual × 10 ft | 10.4 kg |
Movement across the width
How much a board 11 1/4 in (286 mm) wide changes when its moisture content moves by a few percentage points. The estimate uses the total shrinkage above and a linear relation below the fibre saturation point of 23% (Wood Handbook Eq. 4-9). Flat-sawn boards move with tangential shrinkage, quartersawn boards with radial shrinkage.
| Moisture change | Flat-sawn | Quartersawn |
|---|---|---|
| 3 percentage points | 2 mm (0.079 in) | 1.3 mm (0.051 in) |
| 6 percentage points | 4 mm (0.158 in) | 2.6 mm (0.103 in) |
Wood movement across the grain · Moisture content and acclimatising wood
Natural durability
Durability of the heartwood against wood-decay fungi: class 1–2 on the EN 350 scale from 1 (very durable) to 5 (not durable), as reported by Tropix. The rating applies to heartwood only.
Working and finishing
Mineral deposits in some logs severely damage tools, the dust is very irritating and irregular grain can tear. Iroko contains chlorophorin, an antioxidant that can stop finishes with free drying oil from curing: Tropix recommends synthetic-resin paints and varnishes, such as polyurethane, and a pore filler.
Typical uses
- Exterior joinery (windows and doors)
- Boatbuilding
- Decking
- Interior stairs
- Flooring
- Fine furniture and cabinetmaking
- Interior joinery and millwork
Calculate with this material
Species with similar density
- Tauari 620 kg/m³
- Slash pine (Pinus elliottii) 660.8 kg/m³
- Black walnut 616 kg/m³
Sources & references
Uses and working notes summarise the cited source. Check the moisture content, grade and origin of the wood you actually buy.