While most companies track lumber by board foot over linear foot. Crate Pro allows for either. The charts below will assist you in converting the default weight per board foot to linear foot if that's your option. Based on the board length, be sure to divide the values shown by the length to get the correct weight.
The density and weight of lumber varies with the water or moisture content in the wood. Typical weights for green, kiln dried and pressure treated lumber boards are indicated in the tables below.
Note that nominal dimensions are not the same as actual lumber dimensions.
Kiln-dried lumber is green wood that has been dried in a kiln using circulating heated air. This process reduces! the wood's moisture content, which improves its strength and structural integrity, making it ideal for indoor applications where dimensional consistency is important. Pressure-treated lumber is treated with preservatives that help prevent decay from rot, insects, and other causes. Kiln-dried after treatment (KDAT) wood is pressure-treated lumber that has been dried after the pressure treating process, which can help it resist warping, twisting, and checking. KDAT wood can also be painted or stained immediately, unlike most green or wet pressure-treated wood.
Citation
- The Engineering ToolBox (2013). Lumber - Weights. [online] Available at: https://www.engineeringtoolbox.com/green-kiln-dried-pressure-treated-lumber-weights-d_1860.html
Another resource: Citation: The Tiny Life (While not directed at the crating industry - this site provides valuable and easy to understand information)
WEIGHT DIFFERENCE BASED ON TREE SPECIES
The properties used to market lumber vary by tree. The strength and density of each species is different, as is the weight per foot. When calculating the overall weight of your lumber, it’s important to know the species of tree your lumber came from.
TREATED VS UNTREATED
Crate building can greatly benefit from treated lumber. Pesticides and liquid preservatives are absorbed by the porous cells of the wood, making it resistant to damage from pests or water.
However, treated lumber is often significantly heavier than untreated lumber, so knowing whether or not your lumber is treated is a key part of measuring its weight.
WEIGHT BASED ON MOISTURE CONTENT
The higher the moisture content, the heavier the wood. Freshly treated lumber can have a moisture content as high as 75% which slowly decreases over time.
Green wood also has a high moisture content, making boards made from green lumber heavier than those that have been dried. Kiln-dried wood is heated in an oven to evaporate the moisture present in the boards.
WEIGHT DIFFERENCE OF BY LENGTH
This may seem obvious, but length also directly affects the weight of a board. It can be easy to overlook this detail at the end, so don't forget to measure the length of your boards and multiply that by the weight per foot in order to get the most accurate possible weight measurement.
Citation: Hansen Buildings ( Provides the engineering formula for determining board weights - the the site explains to formula)
Is 2×6 lumber heavy?
This is actually fairly important, not just to determine how many boards can be toted around a jobsite by one person, but also in calculating the dead loads which must be carried by structural members such as roof trusses and rafters.
Like most things played around with by engineers, and other people with too much time on their hands, there is a formula to calculate this (please feel free to scream in anguish now):
62.4 X [ G / (1 + G X 0.009) X (m.c.)] X [1 + m.c./100]
Whoo Hoo!! If this isn’t fun…..like watching paint dry?!
