Hardwood Grading Guide

There are several considerations you should take into account when shopping for a quality worktop.

Note that unlike softwood grades, hardwood grades do not indicate the strength of the board. Another difference is hardwood grading does not require a certified or licensed grader. Purchasing lumber from well-established reputable merchant increases your chances of consistently obtaining accurately graded lumber.

Finger-jointed or not? 

• Finger jointing is evidence of a quality top - lesser qualities are simply glued & butted and will regularly open at the seams

Staves - A 40mm stave width is further evidence of a quality top as it is more expensive to manufacture.

• The wood is bought specifically to make tops. 30 / 20mm staves are evidence of a lesser quality top as staves of this size are made from offcuts of wood (See Below) assigned to furniture but are to small to use elsewhere.
  
• Random length staves from 150mm to 1500mm is also evidence that a top is higher end.  Cheaper tops usually have staves that rarely exceed 300mm max in length - again because the wood comes from the furniture industry offcuts.
  

Broadstave is a design statement and refers to tops with staves will usually vary between 50 - 90mm wide and have random lengths.  Broadstave construction should not be confused with:

Planked wood, in which the staves are frequently 150mm wide and run the entire length of the top.

With some exceptions for some species, broad stave & planked tops are typically not manufactured over 2.4m in length as the probibilty of twisting increases immensley.

Solid wood tops are very expensive and very short lived as the wood can think it's a banana in under a month of being placed in an unstable humid environment - i.e. a kitchen.

The hardwood lumber grading rules promulgated by the International Wood Products Association form the basis for much of the international hardwood lumber trade. The standard grades of hardwood lumber as defined by the IWPA (in descending order of quality) are FAS, FAS 1-Face (F1F), Selects, No. 1 Common, No. 2A Common, No. 2B Common, Sound Wormy, No. 3A Common, and No. 3B Common. In practice, some of the above grades are rarely used in the commercial trade and others are typically combined. For example, FAS and FAS 1-Face are usually combined and sold as "Face And Better", FAS and Selects as "Sel and Better",  No. 1 Common and Selects as "No. 1 Common and Better", and No. 2A Common and 2B Common as "No. 2 Common". The grade of Sound Wormy is rarely used commercially.

Grading is based on the size and number of clear cuttings that can be obtained from a board when it is cut up and used for furniture or other products. The higher grades require wider and longer cuttings of clear wood than the lower grades. The specified clear face yield is also realized in a smaller number of cuttings with the higher grades. In the lower grades, the larger number of cuttings permitted provide more leeway in cutting between defects to realize the yield. With a few exceptions, grade is determined from the worst side of a board.

The surface measure of a board is used to determine the number of cuttings permitted for a given grade. For example, the FAS grade specifies a minimum size of 4" x 5' or 3" x 7' for cuttings taken from a board that is at least 6" wide and 8' long. The maximum number of cuttings is nominally four to produce a clear-face yield of 83 1/3 percent. If the surface area of the board is greater than 6 square feet, an additional cutting is allowed if the yield can be raised to 91 2/3 percent.

FAS (Formerly A+)
FAS derives from an earlier grade known as "First and Seconds". It is the best and most expensive grade. Boards 6" and wider, 8' and longer. Yields 83-1/3 percent of clear face cuttings with minimum sizes of 4" x 5', or 3" x 7'. Suitable for fine furniture, interior joinery, solid wood moldings, and other applications where clear, wide boards are needed.

FAS 1-Face (F1F)
One face meets FAS requirements and the poorer face meets Number 1 Common grade requirements. Usually combined with FAS lumber, thereby providing at least one FAS face.

Selects
Face side is FAS, back side is No. 1 Common. Boards are 4" and wider , 6' and longer. Yields 83-1/3 percent clear face cuttings with minimum sizes of 4" x 5', or 3" x 7'. A cost effective substitute for FAS when only one good face is required.

No. 1 Common
Often referred to as "Cabinet" grade in the USA due to its extensive use for kitchen cabinets. Boards are 3" and wider, 4' and longer. Yields 66-2/3 percent clear face cuttings with minimum sizes of 4" x 2', or 3" x 3'. Provides good value, especially if relatively small pieces can be used.

No. 2A Common
Also known as "Economy" grade. Boards are 3" and wider, 4' and longer. Yields 50 percent clear face cuttings 3" and wider by 2' and longer. Grade of choice for US hardwood flooring industry.

No. 2B Common
Same as No. 2A Common, except that stain and other sound defects are admitted in the clear cuttings. An excellent paint grade.

Sound Wormy
Same requirements as #1 Common and better but wormholes, limited sound knots and other imperfections allowed. Not commonly available.

No. 3A Common
Boards are 3" and wider, 4' and longer. Yields 33-1/3 percent clear face cuttings 3" and wider by 2' and longer. Economical choice for rough utility applications:, crates, palettes, fencing, etc.

No. 3B Common
Boards are 3" and wider, 4' and longer. Yields 25 percent clear face cuttings 1-1/2" and wider by 2' and longer. Applications same as No. 3A Common.

Source: International Hardwood Products Association