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.



Red oak is more porous and slightly lighter than white oak, and so tends not to be used only for indoor applications, such as furniture, worktops, countertops, kitchen counters, interiors and floors. It may have a pinkish or reddish tinge, but this depends on the tree and exact species.

Red oaks are named after the principal species, which includes the northern red oak (Quercus rubra) and southern red oak (Quercus falcata). Other species sold alongside include scarlet (Quercus coccinea), willow (Quercus phellos), water (Quercus nigra), black (Quercus velutina) and pin (Quercus palustris), among others.


Design properties
Cost usd/kg
3-5
Embodied energy MJ/kg
1.4-2.1
Carbon footprint kgCO2e/kg
0.15-0.8
Density kg/m3
560-690
Tensile modulus GPa
6.1-14.1
Tensile strength MPa
5.5-97
Flexural modulus GPa
12-13
Flexural strength MPa
70-100
Modulus of rupture MPa
57-96
Compressive strength MPa
8.6-51
Hardness Mohs
1
Janka hardness kN
4.7-5.7
Poissons ratio
0.29-0.56
Thermal expansion (µm/m)/ºC
8-70
Thermal conductivity W/mK
0.15-0.18
Temperature min-max °C
-200 to 150
Thermal
insulator
Electrical
insulator