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Table 27 Maximum spans for built-up ridge beams and lintels supporting roof and ceiling only. No. 1 or No. 2 grade Maximum Span, m (ft.–in.)1, 2,3
Commercial Designation Spruce, pine, or fir (includes Spruce [all species except Coast Sitka Spruce], Jack Pine, Lodgepole Pine, Balsam Fir and Alpine Fir)
Specified Snow Load, kPa (psf)
Lintel Size, mm
1.0
1.5
2.0
2.5
3.0
in.
20.9
31.3
41.8
52.2
62.7
2.88
2.48
2.21
2.01
1.86
9–6
8–2
7–3
6–7
6–1
3.30
2.86
2.55
2.32
2.14
10–10
9–5
8–4
7–7
7–0
3.55
3.10
2.82
2.59
2.40
11–8
10–2
9–3
8–6
7–10
3.53
3.03
2.70
2.46
2.27
11–7
9–11
8–10
8–1
7–5
4.07
3.50
3.12
2.84
2.62
13–4
11–6
10–3
9–4
8–7
4.54
3.91
3.43
3.17
2.93
14–11
12–10
11–5
10–5
9–7
4.09
3.52
3.13
2.85
2.63
13–9
11–6
10–3
9–4
8–8
4.72
4.06
3.62
3.29
3.04
15–6
13–4
11–10
10–10
10–0
5.28
4.54
4.04
3.68
3.40
17–4
14–11
13–3
12–1
11–2
3-ply 38 x 184 2x8
4-ply
5-ply
3-ply 38 x 235 2 x 10
4-ply
5-ply
3-ply 38 x 286 2 x 12
4-ply
5-ply
Notes to Table 27 1. Beam and lintel spans are calculated based on a maximum supported length of 4.9 m (16 ft.–0 in.). Spans may be increased by 5 per cent for supported lengths not more than 4.3 m (14 ft.–1 in.), by 10 per cent for supported lengths not more than 3.7 m (12 ft.–2 in.) and by 25 per cent for supported lengths not more than 2.4 m (7 ft.–10 in.). 2. For ridge beams, supported length means half the sum of the rafter, joist or truss span on both sides of the beam. For lintels, supported length means half the sum of truss, roof joist or rafter spans supported by the lintel plus the length of the overhang beyond the lintel. 3. Provide minimum 76 mm (3 in.) bearing.