When it comes to any building project, from a commercial or residential building to the standard at-home DIY project, everything starts with lumber. The quality of lumber you choose for your project will determine everything from structural integrity to best use to appearance. Whether you’re starting a large commercial building project and need a refresher on lumber grades, or you’re taking your first step into home improvement, here’s everything you need to make sure you can choose the right lumber grades for your project.
Hardwood and Softwood: What’s the Difference?
Before we get into the details of the different lumber grades, we must first understand that all lumber can be generally categorized as either hardwood or softwood. Softwood is any wood that comes from an evergreen tree. It’s lighter, less dense, and tends to be more affordable, due to the fact that softwood trees grow more rapidly and are more abundant than hardwoods. Softwood is ideal for construction because it features a straighter grain, ensuring adequate strength for building components and framing.
Hardwood comes from deciduous trees — the ones that lose their leaves in the fall. Hardwood trees have more interesting and intricate grain patterns that make them the favored choice for artistic and woodworking projects. Since hardwood forms more slowly than softwood, it has a higher density, making hardwood lumber stronger and more durable. For this reason, hardwood is most commonly used in construction applications where longevity and appearance are both major factors, like flooring, cabinetry, furniture making, and more. Hardwood tends to be the more expensive lumber option, as it is less plentiful than softwood.
What Is Lumber Grading?
With a clearer understanding of the differences between hardwood and softwood, we can move onto the specifics of lumber grading. Lumber grades are a standardized way to judge the quality of a wood or piece of lumber. Both softwood and hardwood have separate grading scales. Softwood specifically has a larger variety of grading options depending on the intended application for the lumber.
Lumber grades are important because they tell you what you can expect from the quality of the wood, and how you can use each piece of wood for safe, secure construction. With that in mind, let’s get started with a deeper look into softwood lumber grades.
Softwood Lumber Grades
Softwood lumber grades are divided into categories based on the lumber’s use. Since softwood is so versatile, it can be used for almost everything from supporting and framing a house to paneling it. Having different categories of softwood lumber grades helps make it easier to pick the correct grade for your application, ensuring the proper strength and quality of your build.
Non Stressed Lumber Grades
This first category of softwood lumber is primarily considered in building, for applications that don’t require a great deal of structural support, but that also aren’t highly visible. This lumber is common for use as siding, shelving, and paneling where it will typically be painted over, as well as subflooring and sheathing, where the appearance of the wood doesn’t matter. Non stressed lumber is broken into five different grades, based on the number of defects present in the wood.
Considered a “construction grade”, No.1 lumber might contain some tight knots, but is otherwise relatively defect-free and easy to paint, making it perfect for shelving, siding, or paneling.
A “standard” grade, No. 2 softwood will still accept paint well, but contains numerous larger knots. It’s an economical option that will still do well if you’re planning to cover it with paint.
Considered a “utility” grade of softwood lumber, No. 3 is better for utility applications, like subflooring and sheathing. It won’t accept paint as well as No. 1 or 2, and might have splits and knotholes. It is a great option for unseen building applications.
Economy grade softwood lumber No. 4 will have large areas of waste wood, along with splits, knotholes, and a variety of other defects. This wood won’t accept paint, and is best for sheathing, subflooring, and creation of forms for concrete work.
Also considered an “economy” grade of lumber, No. 5 softwood has the most waste areas and defects. It’s used in similar applications to No. 4 where it won’t be seen, but can make forms, molds or models.
Appearance Lumber Grades
Appearance lumber is any softwood lumber that’s used in applications where it will be seen, such as furniture building. As such, the appearance of the wood is important. It is divided into two categories: Select and Common, each of which can be broken down into their own specific grades.
Select Appearance Lumber: Grades A-D
Select appearance lumber is the highest quality softwood for exposed applications where looks matter. It’s divided into four grades, A-D.
Grade A appearance lumber does not have visible defects with zero apparent knots or splits.
This grade may have a few visible defects, but no obvious knots.
One side might be completely clear of defects, the other may feature a few small knots.
This lumber contains small pin knots and other blemishes, none of which affect the lumber quality.
Common Appearance Lumber
Common appearance lumber grades are split into two categories. This lumber has more defects and knots than select lumber, but some prefer Common appearance lumber as it offers more character to furniture and other visible woodworking applications.
No. 1 Common
Features enough knots to give wood a “knotty” appearance, as with knotty pine. Though knots are present, they are small and tight, making them unlikely to fall out.
No. 2 Common
Chosen for the appearance of the knots like Common No. 1, but tight knots are slightly larger.
Stress-graded softwood lumber is any lumber that has been graded to support weight. Stress-graded lumber is assessed by its load-bearing capacity and is primarily used for building applications that are non-visible and structurally vital, like beams, posts, studs, rafters, and joists.
Stress-graded lumber is divided into four main categories: structural light framing, light framing, stud, and structural joists & planks, each with their own grades to indicate quality.
Structural Light Framing
Structural light framing lumber is lumber that’s between 2″x2″ to 4″ x 4″. Structural light framing lumber is graded from No. 1-3, with the number of defects increasing the higher the number. Structural light framing lumber is commonly used for engineered wood trusses.
Though light framing lumber is classified in the same size range as structural light framing, the applications are slightly different. Lumber in the light framing grade is best for lightweight applications where lumber doesn’t need to bear as much stress, like wall framing, windowsills doors, plates, and blocking. Light framing lumber grades are construction, standard, or utility quality.
The stud lumber grade refers specifically to any lumber sized from 2″x2″ to 4″x18″. This grade applies only to lumber in vertical use in a load-bearing wall application.
Structural Joists and Planks
Softwood lumber grade for structural lumber, categorized as structural joists and planks is the largest of the lumber grades. Lumber used for structural joists and planks must be between 2″x5″ and 4″x18″. Common applications for this grade include lumber serving as floor and ceiling joists, rafters, headers, and trusses. Structural joist and planks are graded from Select structural through No. 3, with No. 3 being the utility or economy class of lumber.
Hardwood Lumber Grades
Unlike softwood lumber, hardwood lumber grades adhere to just one set of grades. This makes them a bit easier to understand. For all hardwood lumber grades, appearance is the one of the most important factors in the grade of a piece of wood since most hardwood is left exposed. Size is the other contributing factor to hardwood lumber grades. Higher grades have a larger percentage of attractive usable material when compared to the lower grades. Let’s take a look at how hardwood lumber grades break down:
Firsts and Second Lumber Grades (FAS)
The most expensive and highest quality lumber, FAS is characterized as boards wider than 6″ and longer than 8′. To qualify as FAS grade lumber, boards must yield 83-⅓ percent clear face cuttings on both sides of the board. The minimum cutting size is 3″ wide x 7′ long or 4″ wide x 5′ long.
FAS One Face (F1F)
An F1F board must meet the same qualifications as FAS lumber, but only on one face. The less attractive face can meet the lower requirements of the number 1 Common grade. This lumber, like FAS lumber, is still suitable for applications like long moldings and furniture.
Selects grade lumber must meet the same requirements as F1F, with a reduced minimum board size. SEL lumber must be 4″ and wider and at least 6′ or longer.
No. 1 Common
A popular shop grade, No 1. Common is great for furniture and primarily used for kitchen cabinets and smaller applications, as well as plank and strip flooring. This type is sometimes referred to as cabinet grade.
No. 1 Common lumber must be at least 3″ wide x 4′ long, with a clear face yield of at least 66-⅔ percent but not as high as the FAS minimum yield.
No. 2A & 2B Common
2A and 2B Common grade lumber is used for paneling and flooring applications, No. 2A & 2B lumber must yield 50 percent clear face cuttings on boards at least 3″ wide with a length of 2′ or more.
No. 3A & 3B Common
Considered “economy,” 3A and 3B hardwood lumber grades must be at least 3″ wide and 4′ long. 3A Common must yield 33-⅓ percent clear face cuttings, while 3B Common can yield 25 percent clear face cuttings. This lumber grade is best for rough utility applications like fencing, palettes, and more.
Lumber Grades Explained
There are a lot of factors that go into grading lumber, but all serve you in distinguishing which type will best suit the needs of your project. If the wood you use doesn’t need to be visible, you can choose a lower grade and save money. If it’s going to be exposed to the eye, a higher grade lumber will give you structural soundness and an attractive finish. Now that you understand both softwood and hardwood lumber grades a little better, you can make a more informed lumber choice for your next project.
Zeeland Lumber & Supply carries a variety of lumber in a variety of grades. No matter the scale of your next project, we have the lumber and the materials you need to get it done. To learn more about the lumber grades we have available, give us a call at (888) 772-2119 or reach out online.