Lumber is a general term that can apply to a variety of different types and sizes of wood used for building various projects in the construction industry. Pieces of lumber are cut lengthwise from trees and usually have a square or rectangular profile. You might wonder where the fence picket you just installed on your fence comes from. Well let’s take a look at the lumber process and learn about some key topics that typically come up.
Some Lumber History
We as a species, have been building with wood since near the beginning of time. The earliest remains of wood construction comes from a location near Nice, France which points to people using wood for construction almost 400,000 years ago. The oldest wood construction that was found still intact is estimated to be about 7,300 years old and is located in northwest Germany.
How Does the Saw Mill Handle Lumber Production?
Fast forward to 1869 and we see the introduction of a large-scale bandsaw that replaced the circular saw for many sawmill operations. We see individual mills specializing in certain cuts of lumber or milling whatever the customer wanted, whereas today everything is more streamlined. Now we have standard dimensions that are divided into three categories depending on the thickness of the piece.
Boards: Nominal thickness of less than 2 inches are classified as boards.
Dimensional: Nominal thicknesses of 2 inches but less than 5 inches are classified as dimensional lumber.
Timbers: Nominal thicknesses of 5 inches and greater are classified as timbers.
Most rough-cut lumber pieces are dried, finished, or surfaced by running them through a planer to smooth all four sides. This is all depending on the grade it is intended for. Because of this process, actual dimensions are smaller than nominal dimensions. A standard 2 x 4 piece of dried, surfaced dimensional lumber actually measures 1.5” x 3.5”. This is important to know when planning your materials list and design for a project. Many homeowners are surprised to know that the true dimension of the lumber they buy is actually smaller than the name it has.
In addition to drying, finishing, surfacing or planing lumber- the mill can also add a pattern which is commonly used for siding and flooring materials. Decorative molding, T&G flooring, and shiplap siding are examples of pattern lumber. We stock a variety of pattern siding profiles and they are generally cheaper than other siding profiles because they are mass produced, which makes them more cost effective.
Raw Materials: Hardwood vs Softwood Lumber
Knowing some background information on the species of tree used to create the lumber for your project is helpful for knowing what to expect when using hardwood vs softwood lumber.
Hardwood: Most hardwood trees have leaves, which they shed in the winter. Hardwood trees include oaks, maples, walnuts, cherries, and birches. Hardwoods are generally more expensive than softwoods and are used for flooring, cabinetry, paneling, doors, and trimwork. They generally comes in lengths from 4-16 ft.
Softwood: Softwood trees have needles instead of leaves. They do not shed their needles in the winter, but remain green throughout the year.. Softwood trees include pines, firs, hemlocks, spruces, and redwoods. Softwoods are used for wall studs, joists, planks, rafters, beams, stringers, posts, decking, sheathing, subflooring, and concrete forms. They usually come in lengths from 4-24 ft.
The Lumber Grading Process
Lumber is graded according to the number and size of defects in the wood. Defects include items such as knots, holes, pitch pockets, splits, and wanes. These defects generally only affect the appearance, but could also affect the strength of the piece of lumber. The higher grades are called select grades. The lower grades are called common grades and are used for general construction where the wood will be covered, such as in framing lumber.
Hopefully this guide has been helpful in understanding a few important parts of the lumber industry. We’ve covered:
- Our history using wood as a building material
- How the mill classifies different types of lumber such as boards, dimensional lumber and timbers
- Nominal vs true measurements of lumber
- Pattern lumber
- The differences between hardwood and softwood lumber
- The lumber grading process
As always, reach out with any questions!
Information for this blog was gathered from: http://www.madehow.com/Volume-3/Lumber.html
