Grading of fresh sawn oak beams- Which grade is right for you?

There is often some confusion amongst our customers about the different grades of fresh sawn beams and which grade is right for their application. This post aims to clear up some of that confusion, and help you make your decision.

There are 3 main grades of fresh sawn oak, QPA, QP1 and QP2. These are French grades, as all of our oak is from France. I will outline the specification for each grade, along with some comments on each.

QPA

The highest grade that is commonly supplied, the specification is as follows:

  • Sawn timber with sharp arris’s; in case of pieces longer than 3 m, wane less than 10% of the face width is permitted across no more than 25% of the length.
  • Sound sapwood permitted on two arris’s if the total width is less than 15% of the face width.
  • Fully or partly inter-grown sound knots are permitted if the diameter is less than one third of the face width.
  • Dead knots, permitted where equivalent to two dead knots with a diameter less than 15 mm per linear meter.
  • Boxed heart permitted, as well as slight traces of heartwood on two faces.
  • Slope of the grain less than 7%, not exceeding 12% locally.
  • Excluded: unsound knots, end shake, frost crack, ring shake, star shake, curly grain, bark pocket, unsound sapwood, brown pith, brown streak, rot, holes.

Broadly speaking this means almost perfect beams, with very few flaws. Typical uses are for highly visible area’s, or focus points. Other than that they tend not to be used due to cost.

QP1

oak beams sussexOur stock grade, used extensively for all building projects. Specification is as follows:

  • Sawn timber with practically sharp arrises, permitting wane less than 10% of the face width across no more than 30% of the length. This width tolerance is increased to 15% for sections above 250 x 250 mm.
  • Sound sapwood permitted on two arrises if the total width is less than 15% of the face width. • Fully or partly inter-grown sound knots are permitted if the diameter is less than half the face width.
  • Two dead knots are permitted per linear meter if less than one quarter of the face width.
  • Boxed heart permitted, as well as traces of heartwood on both faces. Slope of the grain less than 12%, not exceeding 20% locally.
  • Permitted on a limited number of pieces: brown streak, black holes, brown pith.
  • Excluded: unsound knots, frost crack, ring shake, star shake, curly grain, bark pocket, unsound sapwood, rot, white holes.

In practice these beams are perfect for most structural applications, and in many cases are hard to differentiate from a QPA beam.

QP2

Mainly used for garden projects, or where appearance is less important. This grade is noticeably inferior to QP1. Specification is as follows:

  • Timber with wane less than 15% of the face width across no more than 30% of the length.
  • Dead knots permitted if less than one third of the face.
  • One unsound knot is permitted per linear meter if less than 15% of the piece width.
  • Permitted without any restrictions: sound sapwood, fully or partly inter-grown sound knots, sloping grain, brown pith, brown streak, black holes, exposed pith.
  • Permitted on a limited number of pieces: superficial bark pocket, unsound sapwood.
  • Excluded: frost crack, ring shake (unless it cannot be seen on the faces), rot, white holes

 

 

Hopefully this post has cleared up some of the confusion about the differing grades of beams, but if you have any questions or need some advice then please don’t hesitate to contact us