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Wood and Treated Lumber Buying Guide

A man using a circular saw to cut a board, seen from below.

Updated January 28, 2022

Brian G.

By Brian G.

Choosing the right types of wood or treated lumber for your woodworking or construction project may seem like a daunting task, but it’s not as hard as it seems. Here’s the information you need to get started.

Lumber Definitions

Lumber is sold in various forms, sizes, types and cuts. Certain projects may require specific types of wood with one or more of these specific traits:

  • Density: The strength and weight of wood make up its density. Denser wood is best for furniture and building, while less dense wood can be used in making paper or in woodworking projects.
  • Texture: Texture is the wood property that determines the condition of the surface and its stability. It plays an important role in deciding how that type of wood is finished.
  • Color: Color contributes to the personality of wood. For example, red cedar will give you a very different look and character than white pine.
  • Woodgrain: Each tree has its own grain pattern, so two boards of the same species can look very different. Woodgrain is the direction in which the wood cell fibers grow. These variances in grain direction can have a significant impact on your project.


The grain direction is important to consider when building either structural projects or decorative projects, such as furniture or crafts. For instance, when working on a structural application, a straight-grained board is generally the strongest. In more decorative projects, grain with varying characteristics can add beauty and personality to the project. Grain pattern density determines strength. As you’d expect, a piece of lumber with a tight pattern is stronger than one with a loose grain pattern.

Wood Basics

There are two main types of wood to choose from: hardwood and softwood. The terms have almost nothing to do with the actual hardness of the wood.

Hardwoods come from deciduous trees that lose their leaves in the fall. Although there’s an abundant variety of hardwood trees, only 200 are plentiful and pliable enough for woodworking. Hardwood trees are generally slower growing, making the wood denser than softwoods. These woods have a more interesting grain pattern, which makes them popular with woodworkers. Much like our skin, hardwoods have microscopic pores on the surface. The size of these pores determines the grain pattern and texture of the wood, so hardwoods are classified by pore openings as either:  

  • Closed grained (smaller pores), such as cherry or maple
  • Ring porous (larger pores), such as oak, ash or poplar 

Softwoods come from coniferous trees, commonly referred to as evergreen trees. Only 25% of all softwoods are used in woodworking. Softwoods have a closed grain that isn’t very noticeable in the finished product. The most popular softwoods are cedar, fir, pine and spruce. Softwood trees grow faster, and their wood has straighter grain, making it ideal for framing, construction and outdoor projects.


Lumber is available in a variety of sizes and products. When you shop for lumber, you may notice two sizes listed: common and actual. There’s a good reason for this — watch our video about lumber sizes for more info.

Hardwood Grades

Grading designation depends on the number of defects in a board. A lower grade can be perfectly acceptable, depending on placement and usage. Hardwoods are graded by the National Hardwood Lumber Association. Here are the features of each grade:

  • First and Seconds (FAS): Minimum 6 inches by 8 inches, 83% usable material on one face 
  • Select (Sel): Minimum 4 inches by 6 inches, 83% usable material on one face 
  • #1 Common (#1 Com): Minimum 3 inches by 4 inches, 66% usable material on one face 
  • #2 Common (#2 Com): Minimum 3 inches by 4 inches, 50% usable material on one face

Softwood Grades

Softwoods are divided into two categories: dimensional lumber, with a grade based on strength, and appearance boards, which are typically used for woodworking projects. Grades listed here are from highest to lowest.

  • C Select: Almost completely clear of defects; widely used for interior trim and cabinets
  • D Select: Fine appearance, similar to C select; may have dime-sized knots
  • 1 Common: Best material for high-quality pine with a knotty look; knots will be tight, meaning they won’t fall out, and are generally small
  • 2 Common: Tight knots but larger than found in 1 common; often used for paneling and shelving; very suitable for general woodworking projects
  • 3 Common: Knots larger than in 2 common; also used for paneling and shelving but especially well suited for fences, boxes and crates 

Lumber Grade Stamp

Example of lumber-grade stamp information.

When lumber of the same species and size is at the mill, it’s designated and separated by grade. It’s then identified by a stamp and often inventoried by its grade and species. Grade designations depend on particular defects such as knots or wane. Keep your project’s final results in mind when selecting the grade of wood. Grade doesn’t indicate consistency of color or grain patterns. When selecting wood, look for its grading stamp because different lumberyards sometimes use different names for the same grade. Remember: If you’re having trouble figuring it all out, ask for help from Lowe’s experts. The following bullets explain what each lumber stamp you may encounter refers to.

  • Manufacturer: Mill’s number, name or symbol (e.g., 12)
  • Certification Mark: Symbol of the agency providing quality control supervision (e.g., WWP®, the trademark of the Western Wood Products Association)
  • Grade: Often abbreviated, such as 1 common shown above as 1COM
  • Moisture Content (MC): Abbreviations for MC When Board Surfaced: MC 15 is 15% or less; KD or S-DRY is 19% or less; S-GRN is green wood with more than 19% MC (e.g., S-DRY)
  • Species Mark: Symbol or abbreviation for types of trees; example shown is ponderosa pine (e.g., PP)

Treated Lumber

Treated wood use guide chart.

Treated lumber is produced for exterior use only and pressure-treated for ground or above-ground contact. It’s resistant to rotting and insect damage, making it ideal for projects like do-it-yourself garden beds. Boards can be painted or stained once dry. Make sure you work with hot-dipped galvanized or stainless steel fasteners when working with treated lumber.

Good to Know

Treated lumber must be dry before it can be painted.

Dimensional Lumber and Studs

Man using nail gun on stud wall.

Dimensional lumber and studs are milled on all four sides. Available in different lengths, these products are used for a variety of wood projects and construction. 

Plywood and OSB

Woman gluing plywood sheet to wooden frame.

Plywood and oriented strand board (OSB) panels are manufactured (engineered) from various wood products and byproducts. Plywood is produced by layering thin sheets of wood. OSB is made from flakes or chips of wood. Both are made with glue or resin and cured under heat and pressure. These products are used for shelving, subfloors, sheathing and a number of other applications. For more information, read our Particle Board Buying Guide.


Person drilling hole in craft board.

Boards include a broad category of products used for light construction, crafts, woodworking projects, cabinetry, furniture, shelving, internal joinery and molding. Boards can be stained or painted. Larger boards may be solid or edge-glued, which is when two or more boards are glued together to provide a wider size.

MDF Board

Person drilling screw hole in MDF board.

Medium-density fiberboard (MDF) is a wood product that’s created by combining broken-down hardwood and softwood, and binding them with a wax or resin. MDF is typically denser than plywood and used for shelving, cabinets and furniture but has poor moisture resistance.


Person laying deck boards to deck floor and frame.

Decking includes floorboards, railing, balusters and posts in either composite or treated lumber. Composite decking (pictured) is manufactured from wood byproducts and plastic. It’s denser, heavier, longer lasting and more expensive than treated wood. Decking products are milled with rounded edges so they are ready to cut and install. You can learn more about decking by reading our guide How to Design and Build a Deck

Match the fasteners to the material when purchasing treated or composite products. For example, treated wood requires corrosion-resistant screws, and composite decking requires screws with special threads.

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