When Oak is left to dry out naturally (not in a kiln) the timber slowly shrinks and as it does it starts to develop shakes, splits and checks along the surface. When left outside the timber will also steadily go silver grey as it is bleached by the sun.
This natural aging process of Air Dried Oak Beams is often coveted particularly for decorative beams, but they are still strong and stable enough for structural use. Even Fresh Sawn Beams will start to split and check when used in construction and the structural integrity of the beam is not diminished. iWood’s Air Dried beams are graded as QP1 when they are fresh sawn however once they have been air dried they can no longer be graded.
You can buy planed all round air dried oak beams as well as just sawn, however this will take away some of the weathering and the colour of the timber will be more in line with green oak and some of the surface checking and splitting maybe planed away. The moisture content will also be higher as the driest part of the timber is removed (even air dried timber is wet in the middle and will not completely dry out).
Why use Air Dried Oak Beams over fresh sawn?
Air dried Oak is usually used in construction where shrinkage needs to be minimal, as the timber has already had time to dry there will be less movement than with fresh sawn Oak. It can also be used when restoring an old building and you want your Oak to be in keeping with the original brickwork and timber.
It is also highly suited for décor, including mantels, feature beams and decorative trusses. These are usually found in pubs and other public places where there is an emphasis in trying to provide a traditional environment.