Technical Booklet D Structure·Page 34·Table 4B.7
Table 4B.7 Maximum clear span of ceiling joists
This table specifies the maximum clear span in metres for timber ceiling joists of timber strength class C16, based on joist size, spacing, and dead load (excluding self-weight).
Table 4B.7 Maximum clear span of ceiling joists (m)
Timber strength class C16 C16 Dead Load [kN/m2] excluding the self weight of the joist
Size of joist (mm) | Not more than 0.25 | More than 0.25 but not more than 0.50
Spacing of joists (mm) | 400 | 450 | 600 | 400 | 450 | 600
38 x 72: 1.15 | 1.14 | 1.11 | 1.11 | 1.10 | 1.06
38 x 97: 1.74 | 1.72 | 1.67 | 1.67 | 1.64 | 1.58
38 x 120: 2.37 | 2.34 | 2.25 | 2.25 | 2.21 | 2.11
38 x 145: 3.02 | 2.97 | 2.85 | 2.85 | 2.80 | 2.66
38 x 170: 3.63 | 3.57 | 3.41 | 3.41 | 3.34 | 3.16
38 x 195: 4.30 | 4.23 | 4.02 | 4.02 | 3.94 | 3.72
38 x 220: 4.98 | 4.88 | 4.64 | 4.64 | 4.54 | 4.27
47 x 72: 1.27 | 1.26 | 1.23 | 1.23 | 1.21 | 1.17
47 x 97: 1.92 | 1.90 | 1.84 | 1.84 | 1.81 | 1.73
47 x 120: 2.60 | 2.57 | 2.47 | 2.47 | 2.42 | 2.31
47 x 145: 3.30 | 3.25 | 3.11 | 3.11 | 3.05 | 2.90
47 x 170: 3.96 | 3.89 | 3.72 | 3.72 | 3.64 | 3.44
47 x 195: 4.68 | 4.59 | 4.37 | 4.37 | 4.28 | 4.04
47 x 220: 5.39 | 5.29 | 5.03 | 5.03 | 4.91 | 4.63
50 x 72: 1.31 | 1.30 | 1.27 | 1.27 | 1.25 | 1.21
50 x 97: 1.97 | 1.95 | 1.89 | 1.89 | 1.86 | 1.78
50 x 120: 2.67 | 2.63 | 2.53 | 2.53 | 2.49 | 2.37
50 x 145: 3.39 | 3.34 | 3.19 | 3.19 | 3.13 | 2.97
50 x 170: 4.06 | 3.99 | 3.81 | 3.81 | 3.73 | 3.53
50 x 195: 4.79 | 4.70 | 4.48 | 4.48 | 4.38 | 4.13
50 x 220: 5.52 | 5.41 | 5.14 | 5.14 | 5.03 | 4.73
38 x 89 (CLS/ALS): 1.54 | 1.53 | 1.48 | 1.48 | 1.46 | 1.41
38 x 140 (CLS/ALS): 2.84 | 2.79 | 2.68 | 2.68 | 2.63 | 2.50
38 x 184 (CLS/ALS): 4.01 | 3.94 | 3.75 | 3.75 | 3.68 | 3.47
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