Strength Graded timber has been assessed to withstand a certain level of stress. C16 is the standard for structural timber, however some jobs will require the stronger graded C24.
Decking boards are typically made of redwood, which is ideal as they produce straight, stable boards which are insect, rot and weather resistant. The boards don’t require staining and boast a beautiful finish.
CLS stands for "Canadian Lumber Standard", a strength graded and kiln-dried timber planed to a regular finish on all sides.