The NLGA Standard Grading Rules for Canadian Lumber defines: Boards – less than 2 inches in thickness (nominal) Lumber – from 2 to 5 inches in thickness (nominal) Timber – greater than 5 inches in thickness (nominal)

No, the lumber must be grade stamped in accordance with the National Building Code of Canada which requires adherence to “CSA-O141 Softwood Lumber” where it states: The lumber is graded in accordance with grading rules approved by CLSAB. The lumber is inspected and identified in accordance with the Regulations of CLSAB. However, homeowners or builders that want to build a structure with lumber that they have personally milled or purchased that is not grade stamped can contact and make arrangements with a CLSAB Accredited Agency (https://www.clsab.ca/clsab-accredited-agencies/) for the Agency to grade and stamp every piece of lumber to be used [...]