Tempo:
finish is not used, restraint should be provided at intermediate locations between the supports and at distances not greater than 2.1 m (6 ft. 10 in.). Intermediate restraint may be provided by the following methods: 19 × 64 mm (1 × 3 in. nominal) or 38 × 38 mm (2 × 2 in. nominal) cross-bridging; or continuous 19 × 64 mm (1 × 3 in. nominal) wood strapping nailed to the bottoms of the joists or both cross-bridging and strapping. Continuous wood strapping is not required when a ceiling finish is provided.
Floor Performance The floor joist span tables incorporate vibration criteria. The tables recognize that some floor constructions are more “bouncy” or “springy” than others. Therefore, by adding blocking or increasing subfloor thickness, floors will be less springy or bouncy and floor joist spans may be increased. Alternatively, engineered wood products such as laminated veneer lumber joists, wood I-joists and parallel-chord trusses may be used, but vibration criteria must be also be considered for these engineered products.
SUBFLOOR Plywood, OSB or tongue-and-grooved lumber no wider than 184 mm (8 in. nominal) is typically used for subflooring. Minimum thicknesses for subflooring are shown in Table 22 (p. 287). Plywood and OSB are often used as subflooring under wood-strip flooring or as a combination subfloor and underlay for resilient flooring or ceramic tile. When used as a combination subfloor and underlay, the side joints must be supported on blocking at least 38 × 38 mm (2 × 2 in. nominal) fitted between the joists unless the panels have tongue-and-groove edges.
Install subfloors with the direction of the panels or planks at right angles to the floor joists and with the end joints staggered and nailed along the edges at 150 mm (6 in.) on centre and 300 mm (12 in.) at intermediate supports. Use ringed underlay nails, which are designed to resist withdrawal and “nail popping,” or approved staples where the panels provide a combination subfloor and underlay. See Table 23 (p. 287) for sheathing and subflooring fastening requirements. Floor stiffness can be increased and floor squeaks minimized by applying elastomeric glue between the floor joists and the subfloor. The subfloor, adhesive and joists act together as a strengthened floor frame, thus reducing deflection between adjacent joists. All subfloor panels that do not have tongue and groove joints should be covered with an underlay where a vinyl floor covering or ceramic tile is used. An underlay is not required where the edges of the subflooring are supported. All plywood and OSB panels used for subflooring should be the exterior type (manufactured with waterproof adhesives). For a lumber subfloor, 19 mm (1 in. nominal) thick boards are generally used. This thickness can be reduced to 17 mm (11⁄16 in.) where joists are spaced at no more than 400 mm (16 in.) on centre. Apply the boards so that the end joints occur over the joists and stagger end joints throughout the floor. Boards may be applied at right angles to the joists or diagonally at an angle of 45°. When the subflooring is laid at right angles to the joists, place strip flooring at right angles to the subflooring unless an underlay is used. Diagonal subflooring permits strip flooring to be laid either parallel to or across the joists. Nail the boards with at least two 51 mm (2 in.) nails at each support. Lumber subflooring must be covered with a panel-type underlay when the floor is finished with resilient flooring.
Floor Performance The floor joist span tables incorporate vibration criteria. The tables recognize that some floor constructions are more “bouncy” or “springy” than others. Therefore, by adding blocking or increasing subfloor thickness, floors will be less springy or bouncy and floor joist spans may be increased. Alternatively, engineered wood products such as laminated veneer lumber joists, wood I-joists and parallel-chord trusses may be used, but vibration criteria must be also be considered for these engineered products.
SUBFLOOR Plywood, OSB or tongue-and-grooved lumber no wider than 184 mm (8 in. nominal) is typically used for subflooring. Minimum thicknesses for subflooring are shown in Table 22 (p. 287). Plywood and OSB are often used as subflooring under wood-strip flooring or as a combination subfloor and underlay for resilient flooring or ceramic tile. When used as a combination subfloor and underlay, the side joints must be supported on blocking at least 38 × 38 mm (2 × 2 in. nominal) fitted between the joists unless the panels have tongue-and-groove edges.
Install subfloors with the direction of the panels or planks at right angles to the floor joists and with the end joints staggered and nailed along the edges at 150 mm (6 in.) on centre and 300 mm (12 in.) at intermediate supports. Use ringed underlay nails, which are designed to resist withdrawal and “nail popping,” or approved staples where the panels provide a combination subfloor and underlay. See Table 23 (p. 287) for sheathing and subflooring fastening requirements. Floor stiffness can be increased and floor squeaks minimized by applying elastomeric glue between the floor joists and the subfloor. The subfloor, adhesive and joists act together as a strengthened floor frame, thus reducing deflection between adjacent joists. All subfloor panels that do not have tongue and groove joints should be covered with an underlay where a vinyl floor covering or ceramic tile is used. An underlay is not required where the edges of the subflooring are supported. All plywood and OSB panels used for subflooring should be the exterior type (manufactured with waterproof adhesives). For a lumber subfloor, 19 mm (1 in. nominal) thick boards are generally used. This thickness can be reduced to 17 mm (11⁄16 in.) where joists are spaced at no more than 400 mm (16 in.) on centre. Apply the boards so that the end joints occur over the joists and stagger end joints throughout the floor. Boards may be applied at right angles to the joists or diagonally at an angle of 45°. When the subflooring is laid at right angles to the joists, place strip flooring at right angles to the subflooring unless an underlay is used. Diagonal subflooring permits strip flooring to be laid either parallel to or across the joists. Nail the boards with at least two 51 mm (2 in.) nails at each support. Lumber subflooring must be covered with a panel-type underlay when the floor is finished with resilient flooring.
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