Oak, American Red

American red oak is the trade name for eight commercially available species of oak that are sold as both timber and veneer and used in a range of interior applications.

Other Names

Red Oak, Southern Red Oak, Northern Red Oak, Swamp Red Oak, Quercus falcata, Quercus rubra.

Botanical Name

Quercus spp.

Common Form
Sawn
Species Type

American red oak is the trade name for eight commercially available species within the large group of oaks. The trees grow extensively across the eastern part of the USA and are more abundant than the American white oak. This means that there is a good supply of Red Oak as both sawn timber and veneer, and in a range of grades and specifications. In the US red oak is often classified according to its growing region, and sold as northern red oak (Quercus rubra) or southern red oak (Quercus falcata)*.

A highly attractive timber, the sapwood of the red oak ranges from white to light brown, with a pink to red-brown heartwood. While similar in appearance to white oak, red oak has slightly smaller rays and so has a less pronounced figure. The end grain structure of the red oak is also more porous. It is a typically straight-grained wood with a coarse texture, although both colour and texture can vary dependent on the growing region. The name, red oak, comes from colour of the leaves in autumn.

American red oak is a hard and heavy wood with moderate bending strength and stiffness. It has a high crushing strength and steam bends well. AHEC Europe recently commissioned Arup to produce a guide to the use of American Hardwoods in structural applications, including red oak (http://www.americanhardwood.org/). However this guide refers to European Design Standards and Codes and is not, at this stage, applicable to Australia.  

American red oak works relatively easily, machines well, and takes nails and screws, although pre-boring is recommended. The timber performs best when it has been dried slowly, as this reduces the possibility of the wood splitting and warping. As a result of red oak's high shrinkage, it can be susceptible to movement under uneven moisture conditions. The timber can be stained and polished to an extremely attractive finish, which is one of the reasons it is becoming increasingly popular around the world.

In Australia, American red oak is predominantly used in furniture, flooring, joinery, staircases, mouldings, cabinets and boat interiors. While it has structural applications it is yet to be tested for this purpose in Australia.

Red oak timber is readily available throughout Australia from specialist timber suppliers in a range of grades and specifications.

*The properties listed on WoodSolutions refer to the species known as northern red oak (Quercus rubra). Further information about the properties of southern red oak (Quercus falcata) can be found at http://www.americanhardwood.org.

 

Shrinkage

Very Low Low Medium High Very High
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Tangential : Provides a simplified rating for tangential shrinkage. This is the measure of the percentage reduction in dimension from the unseasoned to 12% moisture content condition.

6.60%

Radial : Radial shrinkage is perpendicular to the growth rings. It is shrinkage in the direction towards the centre of the tree. Measurement is % value

2.80%

Unit Movement Tangential: This is the percentage of dimensional change for each 1% moisture content change between about 3% moisture content and the fibre saturation point for the particular species.

0.37%

Unit Movement Radial: This is the percentage of dimensional change for each 1% moisture content change between about 3% moisture content and the fibre saturation point for the particular species.

0.16%

Strength Group Strength groups are given for unseasoned (S1-S7) and seasoned (SD1-SD8) timber in accordance with AS 2878. S1 and SD1 yield the highest strength and stiffness whereas S7 and SD8 yield the lowest.

Very High

High

Reasonably High

Medium High

Medium

Reasonably Low

Low

Very Low

Unseasoned:

S1

S2

S3

S4

S5

S6

S7

S8

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Seasoned:

SD1

SD2

SD3

SD4

SD5

SD6

SD7

SD8

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Stress Grade A stress grade is defined in AS 1720 as the classification of timber for structural purposes by means of either visual or machine grading. The stress grade indicates the basic working stresses and stiffnesses to be used for structural design purposes. Measured in MPa.

Structural
No. 1
Structural
No. 2
Structural
No. 3
Structural
No. 4
Structural
No. 5

Unseasoned:

F8

F7

F5

F4

Seasoned:

F14

F11

F8

F7

F5

Density per Standard Seasoned density is based on moisture content of 12%. Unseasoned density is an approximation as it depends on the moisture content at the time of measurement. Measured kg/m3.

Seasoned:

730kg/m3

Unseasoned:

980kg/m3

Joint Group The joint group is a classification of the strength of a species in joint design. The values are from 1 (very high strength) to 6 (very low strength).

Very High

High

Reasonably High

Medium

Low

Very Low

Unseasoned:

J1

J2

J3

J4

J5

J6

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Seasoned:

JD1

JD2

JD3

JD4

JD5

JD6

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Colour The colour of seasoned heartwood can vary between species and often within a species. The information provided should be used as a general guide only. In most cases, the colour of sapwood is either a lighter shade of the heartwood or a white/cream colour.

  White, yellow, pale straw to light brown Pink to pink brown Light to dark red Brown, chocolate, mottled or streaky
   
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Mechanical Properties

Modulus of Rupture - Unseasoned: This property is a measure of maximum stress which timber can momentarily sustain when loaded slowly and continuously as a beam. Measured in MPa.

53

Modulus of Rupture - Seasoned: This property is a measure of maximum stress which timber can momentarily sustain when loaded slowly and continuously as a beam. Measured in MPa.

87

Modulus of Elasticity - Unseasoned: This property is of importance in determining the deflection of a beam under load — the greater the stiffness, the less the deflection. Measured in GPa.

9

Modulus of Elasticity - Seasoned: This property is of importance in determining the deflection of a beam under load — the greater the stiffness, the less the deflection. Measured in GPa.

12

Maximum Crushing Strength - Unseasoned:

Also referred to as compression strength. This property measures the ability of the timber to withstand loads applied on the end grain. Measured in MPa.

22

Maximum Crushing Strength - Seasoned: Also referred to as compression strength. This property measures the ability of the timber to withstand loads applied on the end grain. Measured in MPa.

44

Impact - Unseasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.

Impact - Seasoned: Provides the Izod value, which is the energy taken in joules (J) to fracture the timber.

Toughness - Unseasoned: This is a measure of timber’s ability to resist shocks and blows, and is synonymous with impact strength. It is measured in Nm.

Toughness - Seasoned: This is a measure of timber’s ability to resist shocks and blows, and is synonymous with impact strength. It is measured in Nm.

High - 25 Nm and above

Hardness - Unseasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.

4.1

Hardness - Seasoned: Refers to the Janka hardness test and is a measure of timber’s resistance to indentation.

5.2

Durability

Low Moderate Reasonably High High
(0 - 5 yrs) (5 - 15 yrs) (15 - 25 yrs) (more than 25 yrs)

In-Ground: Durability is defined as the inherent resistance of a timber species to decay, or to insect or marine borer attack. All references to durability refer to the heartwood only. A scale of low to high (durability class 4 = low; 1 = high) has been adapted for above and in-ground durability.

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(0 - 7 yrs) (7 - 15 yrs) (15 - 40 yrs) (More than 40 yrs)

Above ground: Durability is defined as the inherent resistance of a timber species to decay, or to insect or marine borer attack. All references to durability refer to the heartwood only. A scale of low to high (durability class 4 = low; 1 = high) has been adapted for above and in-ground durability.

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(0 - 20 yrs, usually < 5) (21 - 40 yrs) (41 - 64 yrs) (More than 60 yrs)

Marine Borer Resistance: Indicates whether a species is resistant (R) or not resistant (NR) to marine borer attack.

Lyctid Borer Susceptibility: Indicates whether a species is susceptible (S) or not susceptible (NS) to lyctid borer attack.

Susceptible

Lyctid Borer Susceptibility - Other:

Termite Resistance: Indicates whether a species is resistant (R) or not resistant (NR) to termites.

Not Resistant

Fire Properties

Bushfire Resistance: Naturally bushfire-resisting timbers are those with inherent bushfire-resisting properties. Some species have been tested and a number are in the process of being tested and are measured by Bushfire Attack level (BAL).
BAL -12.5: Ember attack,
BAL – 19: Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 12.5 and 19 kWm3,
BAL – 29: Increasing levels of ember attack and burning debris ignited by windborne embers together with increasing heat flux between 19 and 29 kWm3.

Not tested
Appearance

American red oak stains and polishes to a highly attractive finish, making it a popular choice for architects and furniture makers around the world. It has a white to light brown sapwood with heartwood of pink to red-brown. It has less figure than white oak, due to the smaller rays, and is also more porous at the end grain. It has a coarse texture and its grain is usually straight.

Common Applications

In Australia, American red oak is most often used in interior applications, such as flooring, furniture, joinery, cabinetry and panelling. It is also used in the interior of boats. Red oak is available as a thermally modified timber suitable for exterior decking and cladding.

Workability

Relatively easy to work, American red oak machines well and takes screws and nails, although pre-boring is recommended. It is rated as an excellent timber for drilling, planing and moulding, and it stains and polishes to a high finish.

Origin of timber
North America
Readily Available
NSW
American red oak is readily available in Australia from specialist timber suppliers.
Source of timber
Native Forest
a close-up of a wood sculpture

Mouldings

Mouldings are extremely versatile and durable, enhancing the aesthetics of any interior and functioning as the icing on the cake for designs with a focus on beauty and splendour.

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