Oak

3-5 usd/kg
Circularity potential
Very high
Strength
Medium
Production energy
Low
Stiffness
Medium
Embodied CO2
Low
Density
Low

Traditionally used in a wide range of applications – from toys to floors and boats to buildings – oak is one of the most important hardwoods in the northern hemisphere. It is a durable, hard-wearing and reasonably stable wood with an attractive grain pattern. White oak, in particular, may show distinctive rays when quatersawn. It is available from well-managed and sustainable forests in large quantities.

Oak is rich in tannin. The bark contains the highest concentration and this is why it is used in traditional leather tanning and iron preservation (Japanese teapots), for example. Oak has been reported as a sensitiser, with some people developing an allergic reaction in the skin or eyes after repeated and long-term exposure to the dust.

Acetic acid is known to emit from woods, and oak is thought to emit some of the highest concentrations (up to around 7% by weight over a couple of years). This presents a problem for certain types of interior, such as museums. The acidity is harmful to metals, especially those containing iron. Over time, black stains will develop around iron and steel fixings, such as nails and screws. Therefore, galvanised steel or copper, are recommended.



Compared to red oak, white oak is rot resistant, a little heavier, harder and slightly less reddish in colour. It may also have more pronounced ray flecks when quatersawn, a quality utilised in furniture. And like red oak, it is popular in flooring, worktops, countertops, kitchen counters and architectural surfaces. Its resistance to weathering is utilised in outdoor furniture, boat building and wine barrels, for example. Over time, it will lose its yellowish-colour and turn silvery-grey.

The white oak family is named after the eastern white oak (Quercus alba). Since a single species cannot keep up with demand, several other species that have similar properties are sold alongside. Examples include bur (Quercus macrocarpa), European (Quercus robur), overcup (Quercus lyrata), post (Quercus stellata), Garry (Quercus garryana), swamp white (Quercus bicolor), Chinquapin (Quercus muehlenbergii), swamp chestnut (Quercus michauxii) and chestnut (Quercus prinus).


Design properties
Cost usd/kg
3-5
Embodied energy MJ/kg
1.4-2.1
Carbon footprint kgCO2e/kg
0.8-0.95
Density kg/m3
570-880
Tensile modulus GPa
8.1-13.9
Tensile strength MPa
5.5-112
Flexural modulus GPa
12-13
Flexural strength MPa
70-100
Modulus of rupture MPa
57-105
Compressive strength MPa
8.6-47
Hardness Mohs
1.5
Janka hardness kN
6-7.2
Poissons ratio
0.29-0.62
Thermal expansion (µm/m)/ºC
5-55
Thermal conductivity W/mK
0.15-0.18
Temperature min-max °C
-200 to 150
Thermal
insulator
Electrical
insulator