Types of Lumber

Before You Buy

A kid's bedroom with shiplap walls.

Whether you are taking on a smaller DIY project like shiplapping a bedroom wall, or you're tackling a big job like new construction, familiarizing yourself with these common terms will help you determine to how to choose lumber. 


  • Texture: the feel and condition of the wood’s surface. Wood’s texture is a key part of its stability and its ability to be finished or stained.
  • Color: the color of wood is going to determine the look and style of your project. If the wood won't be visible, as in the case of a structural project, color won't matter much to your selection process. 
  • Density: a wood’s weight and strength. The denser the word, the sturdier the result of your project. This is why the best wood for structural or supporting projects such as beams tends to be denser.
  • Grain: each tree has its own pattern, so no two boards will look the same. It’s important to consider grain when working on projects, specifically decor, to ensure you achieve the look you want. Once again, aesthetic appeal only matters if the wood of your project will be visible.

Hardwood vs. Softwood

Different varieties of wood displayed.

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 common wood that is commercially available, followed by pecan, hard maple and white oak.



Softwood includes cedar, pine, spruce and fir wood. If you’re unsure what wood you’re working with, perform a quick test by pressing your fingernail into the wood. If it dents easily, it’s softwood. The types of softwood you choose will ultimately depend on your project and the look you are trying to achieve. 


  • Typically used in DIY projects or home construction.
  • Inexpensive.
  • Get pressure-treated softwood if it will be outdoors, since softwood absorbs moisture easily. 



Hardwood includes wood like hickory, oak, mahogany, maple and walnut. If you perform the same fingernail test as above, hardwood 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.
  • More costly than softwood.

There are several popular types of lumber:

  • Pine: Relatively inexpensive and easy to find, it is typically used in furniture building and construction.
  • Poplar: Used in cabinetmaking, painted furniture, ceiling moldings and trim. Can mimic expensive hardwood when stained but is also easily scratched.
  • Redwood: Can be used for outdoor projects as it naturally resists rot and is more attractive than pressure-treated wood.
  • Cedar: If treated regularly with preservative, it will resist rotting and be more aesthetically pleasing for outdoor projects than pressure-treated wood.

Lumber Types

Lumber sits in a construction site.

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. Below is a breakdown of the most commonly used types of wood as well as their features and benefits. 

Framing and Structural Lumber

Framing and structural lumber.

The most commonly used lumber, structural lumber, speaks to the 2-x-4 and 4-x-4 used in everyday DIY and construction projects. 

  • 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: 

  • Light framing: 2- to 4-inches thick, 4-inches wide.
  • Structural light framing: 2- to 4-inches thick, 2- to 4-inches wide. 
  • Dimensional lumber and studs: 2- to 4-inches thick, 2- to 4-inches wide.
  • Structural joists and planks: 2- to 4-inches thick, 6-inches wide.
  • Beams and stringers: At least 5-inches wide and 2-inches thick.
  • Posts and timbers: 5-x-5 boards. 
  • Appearance framing: 2-inches wide and 1-inch thick.  

Appearance Boards

Appearance boards on a wall create shiplap.
  • Must be at least 1-inch thick and 2-inches wide. 
  • Two grades of appearance boards: Finish (higher grade) and Select. 
  • Ideal for shiplap projects. 
  • Useful in DIY crafts, interior furniture and decor.
  • Can be used untreated or painted/stained.
  • Available in hard and softwoods.
  • Includes reclaimed wood and barn wood boards. 


Two sheets of plywood are piled up.
  • Made from layers of thin sheets of wood and cured under heat and pressure.
  • Ideal for DIY crafts, shelving and subfloors.
  • Can be used untreated or painted/stained.
  • Available in hard and softwoods.
  • Includes reclaimed wood and barn wood boards. 

MDF (Medium-density fiberboard)

Stacks of MDF board.
  • Medium-density fiberboard is a combination of hardwood and softwood bound with resin.
  • Denser than plywood but is not very moisture resistant. 
  • Can be used for cabinets, interior furniture, shelving.

Decking and Fencing

A new fence stands outside of a home.
  • Available with above-ground contact or ground contact treatment.
  • Includes railings, floor boards, posts and balusters.
  • Composite deck is made of a combination of wood and plastic, making it dense and durable. 
  • Wood decking boards are durable and inexpensive.
  • Composite decking boards are available in a range of colors and won’t warp or crack.
  • Deck tiles creates custom patterns on deck surfaces with an interlocking tile system.

Pressure-Treated and Untreated

Pressure-treated lumber.


  • Available with above-ground contact or ground contact treatment.
  • Choose from wood decking boards, composite decking boards and deck tiles.
  • Wood decking boards are durable and inexpensive.
  • Composite decking boards are available in a range of colors and won’t warp or crack.
  • Deck tiles create custom patterns on deck surfaces with an interlocking tile system.
  • Pressure treated lumber is used for ground and above ground contact. 
  • Great for exterior use and projects that come in contact with cement. It is rot-resistant and can be painted or stained easily. 
  • Heavier than untreated lumber, so it tends to cost more. 
  • Many of the chemicals used in pressure treating lumber contain pesticides. 


  • Some types of lumber, like cypress and redwood, are naturally rot-resistant. 
  • Untreated is great for projects involving animals, children or plants. 
  • Lighter, easier to cut and inexpensive. 

Lumber Grades

Up close shot of hardwood lumber.

Lumber grading determines both price and how the wood will be used. Hardwood and softwood have their own grading systems with hardwood being graded by the National Hardwod Lumber Association. 

Grade refers to both the appearnce and strength of the lumber. Strong lumber with fewer knots or cosmetic blemishes gets a higher grade and price. Never buy a higher-grade lumber than is recommended, as it will affect the overall cost of your project.

Hardwood grades

  • FAS (First and Second) grade: Highest grade of hardwood lumber; 6- x 8-in., 83% defect free on best side.
  • Select: 4- x 6-in., 83% defect free on best side. 
  • No. 1 Common: 3 -x-4 in., 66% defect free on best side. 
  • No. 2 Common: 3- x-4 in., 50% defect free on best side.

Softwood Grades

Softwood is typically split into two categories: dimensional lumber (based on wood's strength) and appearance boards (most commonly used for woodwork). 

  • C Select: Little to no defects. Used for cabinets and trim. 
  • D Select: A few more defects than C select. Great for projects that will be painted. 
  • No. 1 Common: Standard grade lumber with a knotty look. 
  • No. 2 Common: Larger knots. Good for paneling and shelving. 
  • No. 3 Common: Larger knots. Used for shelving, paneling, pallets and fences. 

If "prime" is listed with the grade, such as "prime FAS grade," the lumber has the strength and qualities of the FAS grade, with an even better appearance. Search for prime lumber when the look of the wood is particularly important to you. 

Some types of lumber may be marked as "premium" by the manufacturer, but this is not a standard grade. "Premium" refers to clean appearance of the board but says nothing about the strength or physical quality. 

Lumber Measurements

Different sizes of lumber on The Home Depot store shelves.

In regard to the dimensions of lumber, the term “2-x-4 in.” doesn’t actually mean lumber of 2- inches by 4-inches, but rather 1-1/2- x 3-1/2 in.

Lumber is identified by its nominal size, which is its 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. 

Nominal size is usually the size quoted in DIY project instructions. If actual 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).

Common Lumber Defects
A chart depicts different lumber defects.

Don’t let the word “defects” scare you. 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: 

  • Bow: Warp on the face of a board from end to end. 
  • Cup: Hollow across the face of a board.  
  • Crook: Warp along the edge line. Also known as crown.  
  • Knot: A tight knot is usually fine. A loose or dead knot, surrounded by a dark ring, may fall out or may have already left a hole.  
  • Twist: Multiple bends or warped spots in a board.  
  • Split: Crack going all the way through the piece of wood, commonly at the ends. Usually caused by mechanical processing.  
  • Check: Crack along the wood's annual growth rings, not passing through the entire thickness of the wood. 
  • Shake: A crack that splits the wood along the grain that can pass through its entire thickness. Differs from a split because a shake is usually caused by natural growth of the tree. 
  • Wane: Bark or missing wood on the sides or edges of lumber. 

We carry the right types of lumber for your DIY project. Find the plywood, MDF, pressure-treated lumber and all the tools and supplies you need to complete your woodworking project.

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