How Lumber Is Reduce and Graded (2024)

Have you ever ever questioned why a 2 x 4 piece of lumber doesn’t truly measure 2 inches by 4 inches? What does that mysterious “B&BTR” stamp imply? Understanding lumberyard lingo is useful for any DIY fanatic or house owner planning a venture. On this information, we’ll demystify the terminology, clarify how lumber is processed, and aid you navigate the typically complicated world of wooden.

How Lumber Is Reduce and Graded

Earlier than stepping into the specifics of lumber terminology, it helps to know the journey wooden takes from forest to lumberyard, which shapes the ultimate product’s traits and high quality.

Sawmill Fundamentals

Lumber manufacturing begins on the sawmill, which transforms logs into usable boards. 

Softwood lumber is often lower at 2-inch huge intervals (4, 6, 8, 10, and 12 inches) and even lengths (8, 10, and 12 ft). This standardization gives consistency for development and DIY initiatives. Hardwoods, nonetheless, are lower to no matter width and size the log permits, providing extra selection however much less uniformity.

The lumber trade typically refers to thickness in quarter-inch increments. For instance, a 1-inch board is known as 4/4 (4 quarters), whereas a 2-inch board is 8/4 (eight quarters).

Drying Course of

After sawing, lumber undergoes a drying course of. Freshly lower wooden, generally known as inexperienced lumber, has a excessive moisture content material that have to be lowered earlier than you need to use the wooden. Right here’s the way it works:

Lumber is initially stacked with spacer strips between layers to permit air circulation. Some lumber is left to air dry naturally, which might take weeks or months, relying on the local weather. To hurry up the method, many mills use heated kilns. This methodology not solely dries the wooden sooner however also can kill any bugs within the lumber.

As wooden dries, it shrinks in width and thickness. Even after drying, wooden continues to broaden and contract barely with adjustments in humidity. This is the reason you need to account for wooden motion when constructing cupboards, furnishings, or different wooden constructions.

To assist consumers perceive the moisture content material of their lumber and select the proper lumber for his or her initiatives, mills stamp boards with drying designations:

• S-GRN (Surfaced Inexperienced): Not dried, moisture content material over 19%
• S-DRY (Surfaced Dry): Air dried to a moisture content material of lower than 19%
• KD (Kiln Dry): Dried in a heated kiln to a moisture content material of lower than 19%
• MC 15 (Moisture Content material 15%): Dried to a moisture content material of 15% or much less
• HT (Warmth Handled): Heated to a minimum of 133°F for half-hour on the board’s core to kill any bugs

Planing

After drying, most softwood lumber goes via a planing course of to easy the wooden and create uniform width and thickness. Planed lumber is designated as S4S if it has been surfaced on all 4 sides or S2S if the sides are left tough.

Planing reduces lumber’s dimensions. One-inch boards are usually planed to ¾ inch, whereas 2-inch inventory is diminished to 1½ inches. Planing additionally impacts width, eradicating ½ inch from boards 4 to six inches huge and ¾ inch from boards over 6 inches huge. This explains why a 2 x 4 measures 1½ inches by 3½ inches.

Whereas you may get unplaned lumber straight from sawmills, it’s known as “tough” for good cause. The size can differ from board to board, which could be positive for an unfinished shed however problematic for many different initiatives the place you want consistency.

Hardwood lumber, alternatively, is commonly offered tough. This permits cupboard and furnishings makers to airplane and straighten boards to their specs, giving them extra management over the ultimate product.

Understanding Lumber Grades

Lumber grading is a standardized system that helps consumers perceive the standard and traits of the wooden they’re buying. This technique considers components reminiscent of knots, splits, and different defects that may have an effect on the lumber’s power and look.

Softwood Grades

Softwood lumber, which comes from coniferous bushes like pine, fir, and spruce, is graded primarily based on each look and structural integrity. The most typical grades for development lumber are:

• Choose Structural: That is the best grade, with minimal knots and an almost good look. That is the best choice for high-stress structural functions the place each look and power are equally essential.
• No. 1: Excessive-quality lumber with some small knots allowed. This grade works for initiatives that shall be seen and wish structural integrity.
• No. 2: Normal framing lumber permits for extra knots and imperfections however nonetheless maintains a steadiness between power and workability, making it perfect for many development makes use of.
• No. 3: This lumber is decrease high quality, however nonetheless doesn’t enable defects to go all over the wooden. It’s usable for development functions the place look is much less of a priority, typically in areas not seen.

For appearance-grade softwood, you may see designations like:

• A Choose: Clear with no knots
• B Choose: Has a number of minor defects, however none too obtrusive
• C Choose: Practically away from defects on one face, making it greatest for functions the place one facet shall be seen whereas the opposite stays hidden
• D Choose: Small knots or defects all through

Hardwood Grades

Hardwood lumber from deciduous bushes reminiscent of oak, maple, and cherry makes use of a unique grading system centered extra on look than structural integrity. The Nationwide Hardwood Lumber Affiliation (NHLA) units these requirements:

• FAS (First and Seconds): The very best grade, with massive, clear areas free from defects. It’s typically used for positive furnishings, cabinetry, and different functions requiring a flawless floor. These boards have to be 6 inches or wider and eight ft or longer, with 83% of the board away from knots and defects. 
• Choose: Just like FAS however with smaller board sizes allowed. This grade is great for initiatives that want a steadiness between high quality and value. Permits boards as slim as 4 inches and as brief as 6 ft.
• No. 1 Frequent: Permits for extra knots and defects. Usually used for cabinet- and furniture-making, offering an look with character with out sacrificing an excessive amount of usability. Have to be a minimal of three inches huge and 4 ft lengthy with 67% of wooden clear from knots.
• No. 2 Frequent: Extra defects allowed—typically used for flooring or pallets the place the floor imperfections can add a singular look. It have to be a minimum of 50% away from knots.

Decoding Frequent Lumberyard Phrases

When visiting a lumberyard, you may encounter a wide range of phrases and abbreviations. Right here’s a fast information to some widespread lumberyard lingo:

• B&BTR (B and Higher): This means lumber that meets or exceeds B-grade requirements, guaranteeing the next high quality with fewer defects.
• VG (Vertical Grain): Lumber lower in order that the expansion rings are practically perpendicular to the face of the board, offering a uniform look and higher stability.
• PT (Strain Handled): Lumber handled with preservatives to withstand decay and bugs—perfect for outside initiatives the place publicity to components is a priority.
• MDF (Medium Density Fiberboard): An engineered wooden product made by breaking down hardwood or softwood residuals into wooden fibers, providing a substitute for strong wooden with constant density and stability.

Selecting the Proper Lumber for Your Challenge

Selecting lumber on your venture comes down to a couple components: whether or not it’s for indoor or outside use, how robust it must be, your funds, and the way dry the wooden is. For outside initiatives, go along with pressure-treated wooden or naturally sturdy choices like cedar or redwood so it stands as much as the weather. In the event you want lumber for one thing structural, be certain it’s robust and graded for security. Then again, ornamental items can focus extra on seems to be. Balancing what you want and what you possibly can afford is essential to getting the most effective outcomes with out overspending.

Moisture content material can also be essential, particularly for indoor initiatives. Utilizing correctly dried wooden helps forestall warping or splitting later. In the event you’re ever not sure about what to select, don’t hesitate to ask for assist on the lumberyard. The workers there normally know quite a bit about various kinds of wooden and can provide you ideas to ensure your venture seems good.