Purchasing material can be confusing, we see terms we are not familiar with, and the material we buy is smaller than we thought, hopefully this page will shed some light on the subject.
Hardwood and Softwood
This has to do with the type of tree the wood came from, not the hardness of the wood, for example balsa is a hardwood. Softwoods come from coniferous trees with needle like leaves, most are evergreen. Hardwoods come from deciduous trees with broad leaves
4/4, 5/4, and 6/4 ?
Material will often be listed like this, it simply means that the thickness of the material is measured in quarter of an inch increments, hence 4/4 is one inch thick, 8/4 is two inches thick. Verbally 4/4, 5/4 or 6/4 would be said, "four quarter, five quarter and six quarter."
This means material is surfaced on both faces.
This means that the material is finished on all four sides, for example what what we refer to as a 1 X 4 was a piece of rough sawn material 1" thick and 4" wide and is reduced to 3/4" X 3 1/2" when run through a planer.
Lumber priced by the linear foot means that you pay for each running foot of the material, prices will increase proportionately for wider or thicker material.
One board foot equals 144 cubic inches of material, prices are usually given per thousand feet. To calculate board feet multiply the width in inches by the thickness in inches by the length in inches and divide by 144.
The advantage to suppliers is that only one price has to be given for each grade and species of material since length and width are covered in the volume calculation.
The chart below gives the board feet in various lengths and widths of material one inch thick, for thicker material multiply by the thickness of the material.