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Table 44 Joists for exterior decks Joist span, m (ft.–in.) Joists not incised
Douglas fir - larch (includes Douglas fir and western larch)
Hem - fir (includes western hemlock and amabilis fir)
Spruce, pine, or fir (includes spruce [all species except coast sitka spruce], jack pine, lodgeploe pine, balsam fir and alpine fir)
Northern Species (includes any Canadian species covered by the NLGA Standard Grading Rules
Joists incised
Joist spacing, mm (in.)
Joist Size mm
400
600
400
600
in.
16
24
16
24
38 x 140
2.9
2.3
2.6
2.2
2x6
9-6
7-6
8-6
7-2
38 x 184
3.5
2.8
3.2
2.6
2x8
11-6
9.2
10-6
8-6
38 x 235
4.3
3.5
3.9
3.2
2 x 10
14-1
11-6
12-9
10-6
38 x 140
2.9
2.5
2.8
2.3
2x6
9-6
8-2
9-2
7-6
38 x 184
3.7
3.0
3.4
2.7
2x8
12-1
9-9
11-2
8-10
38 x 235
4.3
3.6
4.1
3.4
2 x 10
14-1
11-9
13-4
11-2
38 x 140
2.8
2.4
2.7
2.3
2x6
9-2
7-10
8-10
7-6
38 x 184
3.7
3.1
3.5
2.8
2x8
12-1
10-2
11-6
9-2
38 x 235
4.3
3.8
4.3
3.5
2 x 10
14-1
12-6
14-1
11-6
38 x 140
2.5
2.0
2.3
1.9
2x6
8-2
6-7
7-6
6-2
38 x 184
3.0
2.5
2.8
2.3
2x8
9-9
8-2
9-2
7-6
38 x 235
3.7
3.0
3.4
2.8
2 x 10
12-1
9-9
11-2
9-2
Notes to Table 44 1. Incising is knife cutting the surface of wood to help perservatives penetrate the wood. 2. Design based on 2001 CAN / CSA O86 3. Live load + 1.9 kPa (40 psf), Dead load = 0.5 kPa (10 psf). 4. Lumber No. 2 and Better grade, pressure treated, wet service conditions.