What is Seasoned, Air-Dried Oak?

seasoned oak

Its so important to understand the differences between Green & Seasoned Oak.

Green Oak Versus Seasoned Oak

The term seasoned oak refers to the state of a freshly cut oak beam that has been left to naturally dry over a period of time.  Normally, oak beams that are left to dry over twelve months can be called ‘seasoned’ or ‘air-dried’.  This is different from kiln-dried oak and in a later post, we will differentiate between all three.

As the tree grew it took water from the ground.  A green oak beam will naturally dry out over time, normally stacked outside or under an open-sided shed.  The airflow will encourage any moisture in the oak to evaporate at approximately 25mm per year.

A green oak beam can have a moisture content of around 60%. A well-seasoned oak beam could reduce this to around 20%.

seasoned oak
seasoned oak

This drying process allows oak beams to become more compact and therefore more stable when subjected to a warmer environment.  Oak beams will naturally change their dimensions and characteristics to acclimatise with their surroundings.  Green oak is more susceptible to movement as the difference in moisture content is more extreme.  Seasoned (Air Dried) Oak is a far more superior product although is harder to source and as a rule, more expensive than green oak.


The characteristic are its discolouration to a silvery grey colour as well as the appearance of cracks found on the face of the beam.  There is also a possibility of the oak having a slight bow and/or twist down its length.  The manufacturing of oak framed buildings would allow the machining of the oak to remove the silver colour and any twist or bow in the beam.  The surface cracks would still be visible and would add to the appeal of owning a seasoned oak beam.

All Oak By Design’s oak frames, buildings and oak porches only use seasoned, air-dried oak. For these reasons, it produces a higher quality and more stable product from day one.

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