C24 Carcassing Timber
C24 timber is kiln-dried treated structural graded softwood that is most commonly used where a grading stamp is required, it is a higher grade structural timber than C16, however, unless C24 grade is specified C16 graded timber is more than sufficient for most purposes and will normally be at a lower cost. You can find C16 graded timber here.
C16 grade timber is produced and available domestically and is provided as a green alternative to C24 which is imported from areas where the climate forces a slower growth rate and produces a tighter grain.
C24 grade timber can used in the construction of floor joists, roof joists and timber framing, it can also be used in many other applications both internally and externally.