Our high-grade CLS is taken from Spruce (Whitewood) and imported from a range of trusted suppliers. CLS is used primarily in timber frame home construction and for internal and partition walls. The product originated for the Canadian market – hence its full name – Canadian Lumber Standard timber. The CLS we stock is taken from Spruce (Whitewood), graded in accordance with British Standards to either C16 or C24 grade and is Kiln-dried, planed and finished with eased edges. Can't find what you're looking for? Need help or advice? Contact your local branch via the number at the top of the screen and speak to a member of our friendly merchant team.