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Table 32 (continued) Maximum spans for roof rafters – specified roof snow loads 2.5 and 3.0 kPa (52.2 and 62.7 psf) Maximum Span, m (ft.–in.) Specified Snow Load, kPa (psf)1
Commercial Designation Spruce, pine, or fir (includes spruce [all species except coast sitka spruce], jack pine, lodgepole pine, balsam fir and alpine fir)
Northern species (includes any Canadian species covered by the NLGA Standard Grading Rules)
2.5 (52.2)
3.0 (62.7)
Rafter Spacing, mm (in.)
Rafter Spacing, mm (in.)
Rafter Size, mm
300
400
600
300
400
600
Grade
in.
12
16
24
12
16
24
No. 1 and No. 2
38 x 89
2.29
2.08
1.82
2.16
1.96
1.71
2x4
7–6
6–10
6–0
7–1
6–5
5–7
38 x 140
3.61
3.28
2.86
3.40
3.08
2.66
2x6
11–10
10–9
9–5
11–2
10–1
8–9
38 x 184
4.74
4.31
3.52
4.46
3.96
3.23
2x8
15–7
14–2
11–6
14–8
13–0
10–7
38 x 235
6.06
5.27
4.30
5.59
4.84
3.96
2 x 10
19–10
17–3
14–1
18–4
15–11
13–0
38 x 286
7.06
6.11
4.99
6.49
5.62
4.59
2 x 12
23–2
20–1
16–4
21–4
18–5
15–1
38 x 89
2.07
1.88
1.62
1.95
1.77
1.49
2x4
6–10
6–2
5–4
6–5
5–10
4–11
38 x 140
3.26
2.84
2.32
3.02
2.61
2.13
2x6
10–8
9–4
7–7
9–11
8–7
7–0
38 x 184
3.99
3.46
2.82
3.67
3.18
2.60
2x8
13–1
11–4
9–3
12–1
10–5
8–6
38 x 235
4.88
4.23
3.45
4.49
3.89
3.17
2 x 10
16–0
13–10
11–4
14–9
12–9
10–5
38 x 286
5.66
4.90
4.00
5.21
4.51
3.68
2 x 12
18–7
16–1
13–2
17–1
14–10
12–1
No. 1 and No. 2
Note to Table 32 1. To determine the specified snow load in your location, contact your municipal building department.