FAS, or Firsts and Seconds, is the hardwood grade which includes the superior “furniture grade” hardwoods. This grade is typically free of defects, but some defects are allowed.
For example, the wider and longer the lumber, the more likely you will find some defect allowed in the wood. Or, when a species has been hit by a disease, such as the current situation with Black Walnut, you are more likely to see defects in the lumber because the best lumber, i.e. the Firsts and Seconds, still has some defect.
In some of these situations, Goosebay is able to source a more expensive “premium” grade of the hardwood species. (This premium hardwood designation is not to be confused with the premium grade of pine.) The premium hardwood grade is a further sort of the Firsts and Seconds. This lumber is also sold at a higher price than the Firsts and Seconds.
If Goosebay has sourced premium hardwood lumber, you will find that each individual piece of wood will have been marked PREM to differentiate it from the FAS lumber in the bin.