Within the timber industry there is often a tendency to present kiln dried oak as the automatic benchmark of quality. In reality, the subject is considerably more nuanced and, in many applications, air dried oak remains not only entirely suitable, but often the preferred material.
At Sykes Timber we work extensively with both air dried and kiln dried oak and firmly believe that timber should be dried appropriately for its intended end use rather than pushed into a one size fits all approach.
Kiln drying unquestionably has an important and necessary role within modern timber production. For interior joinery, cabinetry, flooring, furniture manufacture and centrally heated environments, lower moisture contents are often essential. Properly kiln dried oak provides consistency, improved machinability, reduced movement once installed and compatibility with modern adhesives and finishing systems. In many situations there is simply no practical alternative.
However, there is a significant distinction between carefully conditioning oak through a controlled kiln schedule and aggressively forcing timber down to very low moisture contents purely for speed, throughput or convenience.
Oak is a remarkably dense and complex material. It has developed naturally over decades, sometimes centuries, and it does not always respond kindly to being dried too quickly. Poor or overly aggressive kiln schedules can introduce internal stresses, checking, brittleness, distortion and honeycombing. In some cases the timber may appear dry externally whilst still carrying tension internally, only for movement to reveal itself later during machining or after installation.
Air drying, by contrast, allows moisture to leave the timber gradually and naturally over an extended period of time. The slower drying process generally produces a more balanced board with reduced internal stress and a character that many traditional timber users still strongly favour today.
There is also often a noticeable aesthetic difference. Properly air dried oak tends to retain a softer, more natural appearance and texture, whereas heavily kiln dried material can sometimes appear harsher or more brittle in nature. Many traditional joiners, furniture makers and framers still value air dried oak for precisely this reason.
Historically, much of the finest oak work throughout Britain and Europe was produced from naturally seasoned material. Traditional oak framing, barns, churches and historic buildings that remain standing centuries later are testament to the durability and performance that can be achieved when oak is allowed to season gradually and appropriately.
In our experience, one of the more common issues within the modern market is the over specification of extremely dry oak in applications where it is neither necessary nor beneficial. Exterior oak structures, green oak framing, large section beams, landscaping oak and many semi exposed applications often perform exceptionally well in air dried form and, in certain circumstances, may actually be preferable to highly dried material.
This is not to romanticise air drying or dismiss kiln drying. Quite the opposite. Kiln dried oak is often absolutely essential for precision interior applications, particularly within modern heated buildings where timber is expected to remain stable at much lower equilibrium moisture contents.
The key point is balance and suitability.
Timber should ideally be dried to suit the environment it will ultimately live in. The pursuit of the driest possible oak in every circumstance can sometimes create as many problems as it solves. Equally, supplying air dried oak into highly heated internal conditions without proper conditioning can also lead to avoidable movement and performance issues.
Good oak requires patience. The drying process is not simply a production stage but a fundamental part of the timber’s long term performance. In many respects, how oak is dried is every bit as important as where the log itself originated.
At Sykes Timber we continue to believe there is no substitute for experience, careful grading, sensible drying practices and matching the material correctly to its intended use. Oak is an extraordinary material when handled properly and deserves to be treated with the time and respect it requires.