WOOD SPECIES · Hardwood
Red oak: density, weight and properties
Quercus rubra
Red oak (Quercus rubra) averages 705.6 kg/m³ at 12% moisture content, according to the USDA Wood Handbook. The figures below are averages for clear, mature wood; individual boards vary with origin, growth and moisture.
Key figures
- Density at 12% moisture
- 705.6 kg/m³Specific gravity 0.63 (oven-dry mass, volume at 12%) × 1.12 × 1,000 kg/m³, Wood Handbook Eq. 4-14
- Basic specific gravity (oven-dry mass, green volume)
- 0.56
- Janka side hardness at 12%
- 5,700 N (≈ 1,281 lbf)
- Bending strength (modulus of rupture)
- 99 MPa
- Stiffness (modulus of elasticity)
- 12,500 MPa
- Compression parallel to grain
- 46.6 MPa
- Tangential shrinkage, green to oven-dry
- 8.6%
- Radial shrinkage, green to oven-dry
- 4.0%
- Volumetric shrinkage, green to oven-dry
- 13.7%
- Fibre saturation point
- 30%Not measured: Wood Handbook default
Weight at 12% moisture content
Volume × 705.6 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 | 705.6 kg |
| 1 board foot | 12 × 12 × 1 in | 1.67 kg |
| 1×4 board, 8 ft | 3/4 × 3 1/2 in actual × 8 ft | 2.91 kg |
| 1×6 board, 8 ft | 3/4 × 5 1/2 in actual × 8 ft | 4.58 kg |
| 2×4 board, 8 ft | 1 1/2 × 3 1/2 in actual × 8 ft | 5.83 kg |
| 2×6 board, 10 ft | 1 1/2 × 5 1/2 in actual × 10 ft | 11.4 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 30% (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 | 2.5 mm (0.097 in) | 1.1 mm (0.045 in) |
| 6 percentage points | 4.9 mm (0.193 in) | 2.3 mm (0.09 in) |
Wood movement across the grain · Moisture content and acclimatising wood
Working and finishing
The open pores of red oak let liquids through, so it is not used for tight barrels unless they are lined; quartersawn faces show broad, conspicuous rays. The red oaks shrink fairly strongly on drying, and ties, posts and mine timbers need preservative treatment for satisfactory service (Wood Handbook, chapter 2).
The Wood Handbook names oak, ash, hickory and walnut among the hardwoods with large vessels: for a smooth film finish the pores may need a filler, followed by light sanding.
Typical uses
- Flooring
- Furniture
- Interior joinery and millwork
- Sliced veneer
- Tool handles
- Boxes, crates and pallets
Calculate with this material
Species with similar density
- Hard maple (sugar maple) 705.6 kg/m³
- European beech 710 kg/m³
- Yellow birch 694.4 kg/m³
Sources & references
- USDA FPL · Wood Handbook (2021), ch. 5: Mechanical properties of wood
- USDA FPL · Wood Handbook (2021), ch. 4: Moisture relations and physical properties of wood
- USDA FPL · Wood Handbook (2021), ch. 14: Biodeterioration of wood
- USDA FPL · Wood Handbook (2021), ch. 2: Characteristics and availability of commercially important woods
- USDA FPL · Wood Handbook (2021), ch. 16: Finishing of wood
Uses and working notes summarise the cited source. Check the moisture content, grade and origin of the wood you actually buy.