Familiarizing yourself with the lingo associated with lumber will help you make informed decisions and create durable structures. The following list will cover a variety of lumber terms and abbreviations that are commonly used in the wood industry. S2S, S3S, and S4S refer to the number of random lengths of sides a board has been pre-surfaced to. This saves you time preparing the board for machining.
Softwood
Softwood lumber is generally made from conifer trees with needle or scale-like leaves, like spruce, pine, and fir. It’s easy to work and takes paint fairly well.
Mill Identification – The name of the originating mill, which may be shown on one side of the grade stamp with an abbreviation such as WWPA (Western Wood Products Association).
Annual Ring – A layer of growth added to a tree in one year.
Hardwood
Whether you’re a woodworking hobbyist or a professional builder, the world of lumber is teeming with unique classifications and terminology. Understanding the jargon of the trade will make your next project a breeze. Lumber is graded according to its appearance and structural integrity. Defects such as wane, bird peck (bark pockets), shake, pinholes, unsound knots, and stains are common in hardwood lumber.
A grade stamp is an ink-dispensing mark, indicating a specific piece of lumber or plywood meets the requirements of an accredited grading agency or association. The stamp contains information identifying the species, grade, producing mill, and possibly heat treatment or rot resistance. It is applied by a government agency or private company. The stamp may also contain the grading agency’s trademark or number. The stamp may also indicate the lumber or plywood was kiln-dried.
Heart Face
The heart face refers to the center portion of a board or timber. This term usually applies to lumber species like redwood and hemlock fir, where the center portion of the wood has a distinct color. When building a home with this framing material, it is common for the studs to be trimmed on the center-matched sides so that they can be end-matched. This saves time and materials, reducing the cost of a project significantly.
Individuals can determine if they have a heart-shaped face by measuring their forehead, cheekbones, and jaw widths side-wise from their widest points. This measurement can be compared to other face shapes. Heart-shaped faces tend to have narrower chins than other face shapes. This is due to their resemblance to the curved and joined lines of a heart symbol.
Straight Grain
Whether you’re building your own home or purchasing framing lumber for a commercial project, familiarizing yourself with the common terms used in the wood industry can help make your job easier. Understanding these abbreviations will also enable you to communicate more effectively with suppliers and help ensure the quality of your finished product.
Grain A general term describing the arrangement and direction of wood fibers. It may be straight, curly, wavy, or spiral. Birdseye A figure in some species of wood, usually maple or a few other species, resembling the eyes of a bird. Heavy Dressing Lumber surfaced to a size in excess of the standard dressed size but scant of the nominal size. This material is often intended for remanufacture. Heat Treated (HT) Lumber treated at a high temperature for a specified length of time to kill insects, fungi, and other pests.
Bird’s Eye
A bird’s eye is a decorative circular figure commonly seen in hard maple. It is caused by indented wood fibers that create a light and dark pattern.
HEARTWOOD – The center portion of the tree trunks and branches containing cells that no longer transport water or nutrients. This wood is darker in color than the surrounding sapwood of hardwood species.
BTR – Better, a lumber grading term. This means that the wood is of higher quality than Select.
SEQUENCED MATCHED PANEL SET – A panel set made of consecutively numbered veneer sheets joined together to match the face sequence and grain pattern.
RGH – Rough Lumber, a term that describes lumber that has not been surface planned.
HERRINGBONE – An appearance achieved through book matching adjacent pieces of two sides of veneer at opposing angles. The result is a visual effect of contrasting light and dark patterns.
Bevel
A bevel is a feature on the edges of a part that creates visual refinement and adds a finished look. It also has functional uses, particularly in engineering products that may be subject to unprotected human handling, by reducing sharp edges and creating a safer, blunted surface.
Board Foot – A measurement of lumber used for framing purposes, one inch thick by 12 inches wide and 1 foot long. Book Matched – A technique in veneer production where adjacent sheets are opened like a book and matched with their back sides to the front of the square edge of the next sheet, as opposed to the edge.
Boxed Heart
Boxed heart lumber is milled to exclude the pith or center of the tree. These timbers are usually more costly than those that are Free of Heart Center (FOHC) because they require a larger log to produce. They also tend to twist less and check/split less as they dry.
BF – Board Foot
The standard unit of measurement for lumber is board feet. One board foot is equal to 1 inch in thickness, 12 inches in width, and 1 foot in length.
Carload
Carload abbreviations refer to the specific terms used when describing how lumber is packaged and shipped. Framing lumber is commonly sold by the carload, which is a measurement of 100 linear feet of lumber. Other specific terms include center beaded machining detail on paneling and siding, Roman numeral “C” for hundred Lineal Feet, clear meaning no large defects or knots, machine stress rated referring to lumber tested and approved for a particular strength requirement, and net board measure – actual measurement of a piece of lumber after all machining has been completed. Understanding these lumber abbreviations can help you make more informed purchases for your next project.
S-Dry
In the lumber industry, several abbreviations pertain to how it is seasoned. For instance, when you buy green, unseasoned lumber from a sawmill, the moisture content is often 19 percent or more. As it shrinks and dries, the wood will shift and warp. To prevent this movement, you can use kiln-dried lumber that has a lower moisture content or S-Dry (or sometimes MC-15) lumber that has been heat-treated to kill any insects or fungi.
Knowing the different types of lumber abbreviations can help you navigate the wood industry more easily and confidently. Whether you are a homeowner or a professional builder, understanding these terms can save you time and money while improving the quality of your project. Understanding these lumber abbreviations will also allow you to work with more accurate measurements and ensure that your structures are built safely.
Select Tight Knot
Knotty cedar is beautiful and a great way to add character to your home or project. Select tight knotty, or STK, is a specific type of knotted cedar that has stable, tightly held knots that won’t fall out. It’s a great option for those looking for the unique look of knotty wood without the cost of high-end cedar.
Appearance grades include Finish, Moulding & Better, and 1 Common. These are the highest quality grades used in manufacturing and are suitable for furniture and other applications where long, clear cuttings are required.
