As before, there wasn’t a big problem with size variations because most regions of the country got their lumber from specific regional sources. Regular boards for siding and flooring were more or less 1 inch thick. The evidence that this gives us about what was used at the time is very interesting.įor example, at the turn of the century, the common board thickness for studs, rafters, joists and other framing boards was 2 inches.
If you’ve ever watched “ This Old House“, a show about remodeling houses, you might have seen episodes where they removed boards from very old homes. Locally made lumber became more of a rarity and, as this happened, builders began to notice that the lumber from 1 lumberyard was different from another in terms of the sizes that they were cutting. If a board wasn’t cut to the correct size it was simply made to fit by the builder, usually with an ax) and uniformity of lumber from one lumber yard to the next was practically unheard of.Īs the 19th century drew to a close, however, forests were cut back further and further from the towns and cities where it was needed, and thus it had to be shipped longer and longer distances to the end-user. Keep in mind that, at this time in America’s history, most houses, barns, and other buildings were made by hand-fitting the lumber piece-by-piece, which was extremely time-consuming but made the buildings much more durable and strong. In most cases, the lumber that they produced was cut to the sizes that builders in the specific area were using and asking for, and so they were different from one lumber yard to the next. There were lumber mills all across the United States producing lumber for towns and cities from coast to coast. It was at this time that the lumber used in construction was almost all produced in lumber yards and sawmills that were very close to the town where they would be used. We won’t go back that far but instead to the middle of the 19th century. Of course, wood has been used for centuries all over the world in the construction of homes and other buildings. The history of how lumber sizes were determined is quite fascinating if you go back far enough. Nominal vs Actual Lumber Size Nominal Size – Actual Size In the construction industry, the actual dimensions don’t actually matter anymore because everything has been sized to fit the new, smaller pieces of lumber that are today being produced. Once the lumber is planned to actual size, then the edges are rounded to reduce injury.Īll other dimensional lumber, from 1×2 boards all the way up to 2×12 boards, are planed as well, and thus are smaller than the name they are given suggests. By planning the lumber on all four sides, the original 2×4 is now reduced to 1 ½ inches by 3 1/2 inches. The simple reason why 2×4 is not 2 inches by 4 inches is that lumber mills trim off rough or warped surfaces of a 2×4 to give it a more polished and finished look. Are lumber companies trying to fool us into thinking we’re buying more lumber than we actually are? Quality assurance of Canadian lumber is achieved via a complex system of product standards, engineering design standards and building codes, involving grading oversight, technical support and a regulatory framework.Have you ever purchased a 2×4 piece of lumber at the hardware store and started working on the project to realize that the 2×4 is not 2 inches by 4 inches. Special grade dimension lumber called lamstock (laminating stock) is manufactured exclusively for glulam. Lumber can be used directly as framing materials or may be used to manufacture engineered structural products, such as light frame trusses or prefabricated wood I-joists. The predominant use of dimension lumber in building construction is in framing of roofs, floors, shearwalls, diaphragms, and load bearing walls. The maximum length of dimension lumber that can be obtained is about 7 m (23 ft), but varies throughout Canada. Dimension lumber thicknesses of 64 and 89 mm (2-1/2 and 3-1/2 in) are generally available as surfaced green (S-Grn) only, i.e., moisture content is greater than 19 percent. Air-dried or kiln dried lumber (S-Dry), having a moisture content of 19 percent or less, is readily available in the 38 mm (1.5 in) thickness. For instance, 38 × 89 mm (1-1/2 × 3-1/2 in) material is referred to nominally as 2 × 4 lumber. Lumber can be referred to by its nominal size in inches, which means the actual size rounded up to the nearest inch or by its actual size in millimeters. Design Values for Canadian Species used in Canadaĭimension lumber is solid sawn wood that is less than 89 mm (3.5 in) in thickness.
#4X4 ACTUAL SIZE CODE#
Wood design in the National Building Code of Canada.CSA S-6 Canadian Highway Bridge Design Code.
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