![]() 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.Wood design in the National Building Code of Canada.CSA S-6 Canadian Highway Bridge Design Code.Of course, lengths are customized for each job. A wide range of depths are available, far too many to list here, so please contact your local manufacturer for more information on their offerings - in general depths start at 6" and go up to 30" and beyond. Standard widths are specified in the above publication, but can be customized as needed. The following table comes from the American Institute of Timber Construction's Standard Specification for Structural Glued Laminated Timber of Hardwood Species publication.ĪNSI/AITC A190.1-1992 allows for any width and depth of glue laminated timber. ![]() It is advisable to check with your contractor or lumber supplier before finalizing design details so you aren't surprised by what you receive. However, in some cases, like the big-box hardware stores, the boards come in dimensional widths similar to softwood widths. In most cases, hardwood boards come in random widths to be ripped to size by the woodworker. For instance, hardwood trim that ends up being just over 1" thick (surfaced on 2 sides) is called a five-quarter (5/4) board. 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. Surfaced refers to a finishing process that smooths the lumber to remove all saw marks. Hardwood lumber is sized based on how many sides are surfaced. According to NIST Publication P20, actual lengths must be at least equal to the nominal length, but can be up to 3" longer than the nominal length. ![]() Softwood lumber comes in a number of standard lengths as listed in the table below. North American Standard 8-by Timber (Surfaced 4 Sides, S4S) NOMINAL SIZE (INCHES) North American Standard 6-by Timber (Surfaced 4 Sides, S4S) NOMINAL SIZE (INCHES) ![]() a nominal 8x8 timber has a minimum finished size of 7.25" x 7.25"), most timbers over 7" are finished with 1/2" removed. While NIST Publication PS20 indicates that nominal 7" to 15" thick timbers should have 3/4" removed for a finished dimension (e.g. Softwood lumber that has a thickness over 5" is called timber. North American Standard 4-by Lumber NOMINAL SIZE (INCHES) North American Standard 2-by Lumber NOMINAL SIZE (INCHES) North American Standard 1-by Lumber NOMINAL SIZE (INCHES) ![]() In the United States, softwood lumber is governed by the National Institute of Standards American Softwood Lumber Standard (PS 20). Softwood lumber is generally used for framing walls and floors. ![]()
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