Grading of Sawn Oak

In-House Grading

Here at Border Hardwood, we grade all of our oak in-house to the BS5756 standards. This is the guidelines for grading structural timber in Britain and the structural grades associated with each visual standard. This tells you what a piece of wood can and should be used for; this is essential, for example, to comply with Building Regulations.

The grading of oak beams checks for weaknesses in the beams, such as cracks, splits, and knots. This is why green oak beams with high moisture content are not often used in internal oak work or construction. However, using green oak is easier to work with as it is easier to cut joint and peg holes in the wood. This is why many oak framers use green oak; because as the wood dries and expands the oak frame is strengthened.  For internal construction work, air dried oak beams (dried between 4-7 years), are most often used as they won’t shrink as they dry. This means they are stable enough to use in framing with glazing, internal use or aesthetics. However, air dried oak beams are much more difficult to work with.