Voluntary Product Standard PS 20-20 American Softwood Lumber Standard. Current standards are set by the American Lumber Standard Committee, appointed by the Secretary of Commerce. Other types of lumber, such as plywood and other sheet goods, are offered in prescribed standard sizes but are not referred to as dimensional lumber. For people living in an earthquake zone, this should offer some reassurance. From the Southern Forest Products Association (SFPA). Please consult a professional architect, engineer, consultant, or agency for advice about specific projects, buildings, conditions, codes, and/or regulations. For example, common measurements, like 24, are simply a name that refers to lumber dimensions, but the cross-section dimensions of a piece of lumber are almost always slightly larger than the actual dimensions. The 44s are 3 x 3 and the 16s are of an inch thick and 5 wide. The actual sizes are sizes after drying and surfacing the rough green lumber on all four sides. The actual measurements are the final dried and surfaced size. Builders, design engineers, architects, lumber buyers, and sellers of lumber are all familiar with the differences between the nominal and actual sizes of lumber. The most notable example would be a 24, which is a board of any length that has a thickness of 2 inches & a width of 4 inches (hence 24). In North America, hardwood lumber is usually specified using the quarter system, where a board is identified by its thickness in quarters of an inch. The modern home would not be possible without dimensional lumber. But it wasn't until the 1920s that the term "dimensional lumber" came into popular use to distinguish lumber cut to pre-determined sizes from other types of wood, such as corded wood for fireplaces. ANSI/AITC A190.1-1992 allows for any width and depth of glue laminated timber. The lawsuits were settled, and it was found that the use of nominal sizes to describe lumber sizes was a long-standing and accepted standard industry practice. Engineering Forum The table below is extracted from this publication and shows the Standard Sizes of Southern Pine Dimension, Timbers, Boards, Finish, and Radius Edge Decking. Green southern pine lumber shrinks in width and thickness as it dries, and surfacing removes up to an additional inch from both dimensions. For reference, redwood boards that are used for fence posts require that the board be at least 4 inches wide & 4 inches thick. By clicking Accept All Cookies, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. When it comes to dimensional lumber, theres a difference between a boards nominal size & its actual dimensions. The nominal measurements are the boards size before it has been planed smooth on all four sides. The actual dimension is the size: 1 1/2 inches by 3 1/2 inches, for example. Dry lumber that has been seasoned or dried to a moisture content 19% or less and green lumber has a moisture content of greater than 19%. The tables below provide both the nominal and actual lumber dimensions for many common North American lumber sizes. Lengths typically are shown as the last number. The actual vs. nominal sizes for common sizes of dimension lumber: Shrinkage is more pronounced laterally (across the grain) than it is longitudinally (with the grain), so a board sold as an 8-foot 2 x 4 is generally very close to the full 8 feet in length. Technically, you can define dimension lumber as sawed softwood lumber from 2 to 5 inches (5 to 12.7 centimeters) thick and from 4 to 12 inches (10.2 to 30.5 centimeters) wide. One board foot is equal to 144 cubic inches of wood. The nominal measurements are a board's size before it has been planed smooth (surfaced) on all 4 sides. Typical dimensional lumber: 2x4s, 2x6s, and 4x4s. sizes. Mechanical Tolerance Variations of Lumber: Per. For instance, hardwood trim that ends up being just over 1" thick (surfaced on 2 sides) is called a five-quarter (5/4) board. If youre confused if your lumber is a hardwood or softwood, be sure to check out this article for clarification. Believe me, weve been there! The following data is standard reference and size data for commercially available lumber within the USA. The Southern Forest Products Association (SFPA) publishes a comprehensive pamphlet, The Southern Pine Use Guide,. This is a well-established industry practice. Get DIY project ideas and easy-to-follow crafts to help you spruce up your space. x 4 in. Softwood lumber comes in a number of standard lengths as listed in the table below. Softwood Lumber Dimensions: Softwood lumber is measured in a number of different standard sizes. It can be difficult to remember the difference between nominal and actual dimensions. The nominal dimension is the name of the lumber: 2x4 or two-by-four, for example. Nominal Size vs. Actual Size Dimensional Lumber, How to Build Your Own Floating Wood Deck With Concrete Blocks, Properly Space Your Shelves and Wall Supports. Engineering Book Store The actual size of a 24 is a inch smaller than its nominal dimensions. These are the ones we have on our shelf. Nothing completes a wood piece better than a neatly applied finish. Thus, its no surprise that home improvement stores typically offer redwood as dimensional lumber rather than in board footage sizing. Not only are different measurement standards used, but the sizing also depends on whether the stock is surfaced on one side (S1S) or on two sides (S2S). This is common knowledge for the experienced lumber user and is the result of the fact that wider lumber shrinks more in width than the narrow lumber during drying. Nominal vs. Actual Measurements of Dimension Lumber, Learn the Real Reasons a 2 x 4 Does Not Measure 2 Inches by 4 Inches, Understanding Board-Foot Pricing for Hardwoods, How to Use Construction Lumber in Fine Woodworking, Your Quick Guide to Identifying Plywood Sizes. Generally, any associate at a lumberyard or home improvement store will have a full understanding of the individual nuances between measurements and the different types of lumber. Disclaimer In reality, a 24 actual size measures 1-1/2 inches by 3-1/2 inches. The reason for the differences is because lumber sizes are traditionally given in their nominal size. These differences in width are the same for boards. Now that weve clarified the measurements for thickness & width, its time that we drop another twist into the story. A sheet of 1/2-inch plywood is really 15/32 inch thick, while a 3/4-inch sheet is 23/32 inch thick. The reason for this is that boards typically arent cut to length until after theyve been cured & planed. Melville, NY 11747, Terms & Conditions Therefore, you can cut the boards a little smaller than 24 inches and still leave it large enough to dress after drying at 1 inches thick and 3 inches wide. CORPORATE HEADQUARTERS The first dimensions are its. Online Books & Manuals During this period, the building industry sought to control costs and minimize waste by developing standard sizes and grades for building timber. The 44s are 3 x 3 and the 16s are of an inch thick and 5 wide. Many older homes have nominal dimension 2x4s that are actually 2 inches by 4 inches. 2022 Southern Pine Inspection Bureau | All Rights Reserved | SitemapP.O. Deane is a member of The Spruce's Home Improvement Review Board. Nominal means name, or in this sense, existing in name only. For example, a 24 actual dimensions measure 1-1/2 inches by 3-1/2 inches. Machine stress-rated and machine-evaluated lumber is readily available for end-uses where high strength is critical, such as truss rafters, laminating stock, I-beams and web joints. This standard lists the nominal and minimum dressed sizes for all categories of structural and nonstructural lumber. Dimension lumber is lumber cut and finished S4S, (surfaced four sides) and is available in standardized sizes. With that being said, its still worth discussing the other factors since they can be more influential than affordability. Engineering Toolbox Save my name, email, and website in this browser for the next time I comment. Click to share on Facebook (Opens in new window), Click to share on Pinterest (Opens in new window), Compressive Strengths of Popular Softwoods. Copyright 2022 Archtoolbox. All rights reserved They enjoy teaching readers how to renovate with confidence. For the average do-it-yourselfer, most long, thin lumber that will be used for building is considered to be dimensional lumber. The lumber size chart below will help you know what to buy and how to properly plan your project. Keep in mind that the actual size of a piece of lumber is anywhere from inch to inch less than the nominal size. We help everyday people bring superior craftsmanship to their home workshop. Sheet goods, though cut to standard sizes, are not considered to be dimensional lumber. As an example, you can imagine how much more difficult it would be to remodel a house if the wall studs had irregular dimensions. Training Online Engineering, Structural Wood Lumber Engineering Properties | Modulus of Elasticity of Wood | Wood Engineering Design Data, Structural Wood Lumber Engineering Properties Table Chart | Modulus of Elasticity of Wood, Engineering Properties Structural Lumber Douglas-Fir-Larch, Hem-Fir, Spruce-Pine-Fir, Engineering Properties Southern Pine Lumber, Wood Lap Joint Glue Strength Design Equations and Calculator, Lag Screws in Wood Pullout Resistance Force Formulae and Calculator. However, after drying and surfacing, the boards became smaller, approaching the now standard 24 dimensions of 1 x 3 inches. First, its good to note that there are a few nuances in terminology. x 8 ft.". Materials & Systems > Wood / Plastic / Composites. The most commonly available dimension lumber sizes are 24 through 212. To make things more complicated, hardwood sizing standards are different from softwood standards. Hardwood board widths vary. Additionally, hardwood may be sold in quarters. | Contact, Home One rule of thumb for quickly calculating actual lumber width: subtract 1/2-inch from the nominal width on all except for 1-inch nominal width boards. Each quarter refers to 1/4 inch of thickness, meaning that a 5/4 board is roughly 1 1/4 inches thick. After it has been planed, smoothed and kiln dried, the board will come in at a slightly smaller size which is measured as the actual lumber size. The length of dimension lumber can range from 6 to 24 feet. Making Manzanita has participated in One Room Challenge and was a finalist in the Fall 2019 Jeffrey Court Renovation Challenge. Hardwood lumber is sized based on how many sides are surfaced. Voluntary Product Standard PS 20-05, American Softwood Lumber Standard. | Feedback | Advertising The Southern Forest Products Association (SFPA) publishes a comprehensive pamphlet, The Southern Pine Use Guide, that also lists nominal and standard sizes for all Southern Pine products along with design values, span tables, and grade descriptions. The applicable standards are based on results of tests conducted in cooperation with the USDA Forest Products Laboratory. https://www.southernpine.com/publications/. ?from the slow-growing virgin forests common over a century ago to the fast-growing plantations now common in today's commercial forests. The label should also state the actual or minimum measurements.. Thus, a dimensional 2x4 board can be 12 feet long, for example, but that length is not figured into the dimensions. For example, AA plywood has a furniture-grade finish on both sides, while BC plywood will be graded B on one side and C on the other. Dimension lumber can be purchased as dry or green. Excel App. According to the American Wood Council, the National Institute of Standards and Technology permits stores to label lumber with nominal dimensions, if the label or other sign clearly states that the size given is a, Technically, dimension lumber is defined as sawed softwood lumber from 2 to 5 inches (5 to 12.7 centimeters) thick and from 4 to 12 inches (10.2 to 30.5 centimeters) wide. The Southern Forest Products Association (SFPA) publishes a comprehensive pamphlet, The Southern Pine Use Guide, that also lists nominal and standard sizes for all Southern Pine products along with design values, span tables, and grade descriptions. As early as the 1870s, lumberyards began to use the now-familiar 2x4 or 2x6 designations for dimensional lumber. Additionally, the use of standard dimensions enables architects & designers to have some degree of predictability when designing a structure. From the Southern Forest Products Association (SFPA). Its also the most common lumber for building as its ready to use and universally consistent in sizing. Your email address will not be published. It is advisable to check with your contractor or lumber supplier before finalizing design details so you aren't surprised by what you receive.