Standard dimension lumber sizes produced in North America are listed as surfaced dry sizes (19 percent moisture content or less) in the table below. The availability of lumber sizes varies somewhat according to the area of the country from which the raw material originates. Lengths up to 6.1 m ( 20' ) are commonly available from western Canada and up to 4.9m (16') from eastern Canada. Longer lengths are available on special order. They are also available in the form of fingerjoined lumber.