The term "C24 grade" is used to describe a higher timber quality than that of C16. C24 timber is a premium choice that can support higher loads and wider spans. Only timber imported from areas where the weather conditions demand a slower growth rate (and hence a tighter grain) achieves a C24 grade.Thanks to the protective treatment and C24 grading of 5x2 treated timber, it is suitable for use in a variety of indoor and outdoor applications.