True technical dimensions for standard rough lumber

The standard nominal 1" boards are 7/8" thick.
The standard nominal 2" boards are 1-3/4" thick.
True technical widths are 1/8" under the nominal width.

Example :
A 2"x4"x8' board true dimensions are 1-3/4" x 3-7/8" x 8'0-1/2"

True technical dimensions for planed/molded lumber

True technical thickness for a planed board is usually 1/2" under the nominal thickness if planed on both sides. (except for 1" board which are 11/16")
True technical width for a planed board is usually 1/2" under the nominal thickness if planed on both edges.

Example :
2"x4"x8' planed true dimensions are 1-1/2" x 3-1/2" x 8'0-1/2"

Moisture content

Green lumber that has just been sawn has a high moisture content. For Eastern hemlock, when it exits the sawing line, moisture content is around 50% in the lumber. However, there are variations from piece to piece since lumber is made from living organisms that differ depending on their growth and environmental conditions.

Moisture content will vary within the lumber according to its surroundings and the degree of exposure to the elements. In order for the lumber to dry, there must be air movement or air change since air gets loaded with moist from the lumber.

Lumber that is installed while still green will change in dimensions, mainly in width and thickness. Shrinkage of 4-5% is noticeable and needs to be considered when planning your projects.

Our sales team will be happy to help you accurately measure the impact of moisture on your projects.