Tempo:
Lumber and Other Wood Products
Many types of wood components can be used in wood-frame construction. The framing forms the structural shell that encloses and divides spaces, to which finishes are applied. Lumber is commonly referred to by its nominal dimensions (size before planing and drying), which are larger than its actual, finished dimensions. For example nominal 2 by 4 in. lumber is actually about 11⁄2 by 31⁄2 in. Timber is lumber 114 mm or more (5 in. nominal) thick in its smaller dimension. Table 7 (p. 267) shows the grades, common grade mixes, principal uses and grade categories for the various sizes of dimension lumber. There are also decking, board and finish lumber groupings. Metric sizes of softwood lumber are expressed in millimetres of actual thickness and width after surfacing. The concept of “nominal size” is not used with metric dimensions; therefore, metric lumber dimensions are actual sizes. Table 8 (p. 268) relates the current metric dimensions to the imperial equivalents (actual and nominal).
GRADE MARKS Lumber used for construction in Canada is grade-stamped to show that it conforms to the National Lumber Grades Authority (NLGA) grading rules for Canadian lumber. The grading and grade marking of lumber must also conform to CSA Standard O141-05 (R2009): Softwood Lumber. A grade stamp indicates the grading agency, the species or species combination designation, the grade, the moisture content at the time of manufacture and the mill number. Facsimiles of Canadian grade marks are shown in Table 9 (p. 269). “S-GRN” in the grade mark signifies that the lumber was surfaced at a moisture content higher than 19 per cent to a size that would allow for natural shrinkage during seasoning. “S-DRY” in the mark indicates the lumber was surfaced at a moisture content not exceeding 19 per cent. KD (kiln-dried) indicates that lumber has been dried in a kiln to a moisture content of 19 per cent or less. The moisture
Many types of wood components can be used in wood-frame construction. The framing forms the structural shell that encloses and divides spaces, to which finishes are applied. Lumber is commonly referred to by its nominal dimensions (size before planing and drying), which are larger than its actual, finished dimensions. For example nominal 2 by 4 in. lumber is actually about 11⁄2 by 31⁄2 in. Timber is lumber 114 mm or more (5 in. nominal) thick in its smaller dimension. Table 7 (p. 267) shows the grades, common grade mixes, principal uses and grade categories for the various sizes of dimension lumber. There are also decking, board and finish lumber groupings. Metric sizes of softwood lumber are expressed in millimetres of actual thickness and width after surfacing. The concept of “nominal size” is not used with metric dimensions; therefore, metric lumber dimensions are actual sizes. Table 8 (p. 268) relates the current metric dimensions to the imperial equivalents (actual and nominal).
GRADE MARKS Lumber used for construction in Canada is grade-stamped to show that it conforms to the National Lumber Grades Authority (NLGA) grading rules for Canadian lumber. The grading and grade marking of lumber must also conform to CSA Standard O141-05 (R2009): Softwood Lumber. A grade stamp indicates the grading agency, the species or species combination designation, the grade, the moisture content at the time of manufacture and the mill number. Facsimiles of Canadian grade marks are shown in Table 9 (p. 269). “S-GRN” in the grade mark signifies that the lumber was surfaced at a moisture content higher than 19 per cent to a size that would allow for natural shrinkage during seasoning. “S-DRY” in the mark indicates the lumber was surfaced at a moisture content not exceeding 19 per cent. KD (kiln-dried) indicates that lumber has been dried in a kiln to a moisture content of 19 per cent or less. The moisture
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