When it comes to buying lumber, there are a lot of choices to make. Choosing lumber means understanding grain patterns, grades, types of wood and more. Which type of lumber you end up using for a project depends on its purpose.
For structural needs such as joists or beams, the look of the lumber isn’t a top priority. However, if the wood is going to be visible, you may want a higher grade of lumber. Use this guide to learn lumber terms, measurements and grades so you can understand how to choose the right lumber for your next project.
Whether you are taking on a smaller DIY project like shiplapping a bedroom wall, or you're tackling a big job like new construction, these common terms will help you determine to how to choose lumber.
There are two categories of wood: hardwood and softwood. The lumber industry uses a scale called the Janka Rating System to measure and rank the relative hardness of wood. Hickory is the hardest, commercially available common wood. Next in line are pecan, hard maple and white oak.
Hardwood includes wood like hickory, oak, mahogany, maple and walnut. If you’re unsure what wood you’re working with, perform a quick test by pressing your fingernail into the wood. If it is hardwood, it will not dent easily. The types of hardwood you choose will ultimately depend on your project and the look you are trying to achieve. Typically used in cabinetry, flooring and woodworking. Usually requires more upfront investment than softwood.
While terms like boards, studs and plywood all refer to types of lumber, they should not be used interchangeably. Each type of lumber is designed to be used for specific building purposes. Read on for a breakdown of the most commonly used types of wood as well as their features and benefits.
The most commonly used lumber, structural lumber, are the 2-foot x 4-foot and 4-foot x 4-foot boards used in everyday DIY and construction projects.
Framing and structural lumber follows standard building dimensions (thickness and width). Standard dimensions allow for faster building as less cutting is needed on site.
Structural lumber can be broken down into seven categories:
Appearance boards are chosen primarily based on how they look rather than their strength. They must be at least 1-inch thick and 2-inches wide. There are two grades of appearance boards, “Finish” (a higher grade) and “Select”. Appearance boards are ideal for shiplap projects, DIY crafts, interior furniture and decor.
Appearance boards can be used untreated or painted/stained. They are available in hardwoods, softwoods, reclaimed wood and barn wood boards.
Plywood is made from layers of thin sheets of wood and cured under heat and pressure. It’s ideal for DIY crafts, shelving and subfloors. Plywood can be used untreated, painted or stained. It’s available in hardwood and softwood veneers.
MDF, or Medium-Density Fiberboard, is a combination of hardwood and softwood bound with resin. It’s denser than plywood but is not very moisture resistant. MDF is ideal for the unseen parts of cabinets, interior furniture or shelving.
Deck and fencing lumber includes railings, floor boards, posts and balusters. It is available with above-ground contact or ground contact treatment.
Pressure-treated lumber is wood that has been processed with preservatives to last longer. It is available with above-ground contact or ground contact treatment.
Untreated lumber is great for projects involving animals, children or plants. Some types of lumber, like cypress and redwood, are naturally rot-resistant. Untreated lumber is also lighter, easier to cut and budget-friendly.
Grade refers to both the appearance and strength of the lumber. Hardwood and softwood have their own grading systems. Lumber grading determines both price and how the wood will be used. Strong lumber with fewer knots or cosmetic blemishes gets a higher grade and price. Some types of lumber may be marked as “premium” by the manufacturer, but this is not a standard grade. “Premium” refers to the clean appearance of the board but doesn’t verify the strength or physical quality.
Hardwood is graded by the National Hardwood Lumber Association. Hardwood grades are:
Softwood grades typically fall into two categories: dimensional lumber (based on the wood’s strength) and appearance boards (most commonly used for woodwork).
Tip: If “prime” is listed with the grade, such as “prime FAS grade,” the lumber has both the qualities of the FAS grade and a fine appearance. Search for prime lumber when the look of the wood is particularly important for a project.
Lumber is identified by its nominal or named size. The nominal size is the lumber’s rough dimension before it is trimmed to its finished size at the lumber mill. This is the size that appears on the tag in store. Actual lumber sizes are approximate dimensions after trimming.
For example, for the dimensions of lumber, a tag that says “2-inches x 4-inches” doesn’t actually mean lumber that’s two inches by four inches in measure. Rather “2-inches x 4-inches” is in actuality 1-1/2-inches x 3-1/2-inches.
Nominal size is usually the size quoted in DIY project instructions. If actual lumber sizes are required, that will be noted. These measurements clarify what you’ll see on the tag in stores (nominal size) versus the actual measurements of the lumber (actual size).
All wood has natural defects that can add character. There are, however, some defects in structural lumber that you shouldn’t overlook.
Here are the most common lumber defects:
Choosing the lumber for your next project just got easier. Now you know which types of wood work best for which jobs. Whether you’re building a home or starting a renovation project, the right lumber makes all the difference. Find the plywood, MDF, pressure-treated lumber and all the tools and supplies you need to complete your woodworking project. Ready to get started today? Reach out to our truck rental department for pickups, vans or moving trucks to haul lumber and more.