What is Seasoned Oak (Air-Dried)?
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’. This is different to kiln-dried oak and will be discussed in a later post.
A freshly cut oak beam is normally called ‘green’ and will contain a large of amount of moisture. This was inherited from the tree as it grew. A green oak beam will naturally dry out over time, normally stacked outside or under an open-sided shed. The air flow 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%.
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 oak is a far more superior product although is harder to source and as a rule, more expensive than green oak.
The characteristic of seasoned oak is the 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 porches only use seasoned, air-dried oak. For these reasons, it produces a higher quality and more stable product from day one.