Tempo:
CHOOSING THE SIZES AND SPACING OF FLOOR JOISTS Problem
Selection
Select a floor joist that is acceptable for the following conditions.
Use Table 20 (p. 285).
Conditions
Joists are supporting the living room floor
Joist span is 3.75 m (12 ft. 3 in.)
Bridging will be installed
Basement ceiling will not be finished
Species group and grade specified are SPF No. 2 and better Subfloor is 15.9 mm (5⁄8 in.) plywood nailed in place Also note that drywall or gypsum board ceiling finish can be considered as strapping. For this example, floor joists can be considered braced with bridging and strapping.
Acceptable floor joist sizes for this application include: 38 × 184 mm at 300 mm (2 × 8 in. at 12 in.) on centre or 38 × 235 mm at 600 mm (2 × 10 in. at 24 in.) on centre Note 1: Any spacing less than 600 mm (24 in.) on centre for the 38 × 235 mm (2 × 10 in.) is acceptable. Note 2: In accordance with the National Building Code, the metric spacing of wood framing members is expressed as a “soft” conversion from the actual imperial dimensions. For example, spacing of 12, 16 and 24 inches on centre is converted to 300, 400 and 600 mm. on centre, respectively. In order to suit the imperial sizes of common 1220 × 2440 mm (4 × 8 ft.) panel products, such as gypsum board, OSB and plywood, the actual spacing of framing members is commonly adjusted to 305, 406 and 610 mm on centre, respectively.
67 Floor joists bearing on beam and foundation wall joist span = 3.75 m (12 ft. 3 in.)
Selection
Select a floor joist that is acceptable for the following conditions.
Use Table 20 (p. 285).
Conditions
Joists are supporting the living room floor
Joist span is 3.75 m (12 ft. 3 in.)
Bridging will be installed
Basement ceiling will not be finished
Species group and grade specified are SPF No. 2 and better Subfloor is 15.9 mm (5⁄8 in.) plywood nailed in place Also note that drywall or gypsum board ceiling finish can be considered as strapping. For this example, floor joists can be considered braced with bridging and strapping.
Acceptable floor joist sizes for this application include: 38 × 184 mm at 300 mm (2 × 8 in. at 12 in.) on centre or 38 × 235 mm at 600 mm (2 × 10 in. at 24 in.) on centre Note 1: Any spacing less than 600 mm (24 in.) on centre for the 38 × 235 mm (2 × 10 in.) is acceptable. Note 2: In accordance with the National Building Code, the metric spacing of wood framing members is expressed as a “soft” conversion from the actual imperial dimensions. For example, spacing of 12, 16 and 24 inches on centre is converted to 300, 400 and 600 mm. on centre, respectively. In order to suit the imperial sizes of common 1220 × 2440 mm (4 × 8 ft.) panel products, such as gypsum board, OSB and plywood, the actual spacing of framing members is commonly adjusted to 305, 406 and 610 mm on centre, respectively.
67 Floor joists bearing on beam and foundation wall joist span = 3.75 m (12 ft. 3 in.)
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