Technical Booklet D Structure·Page 32·Table 4B.6
Maximum clear span of floor joists in timber strength class C24
Table 4B.6 provides maximum clear spans in metres for timber floor joists of strength class C24, varying by joist size, spacing, and dead load applied to the floor. The table covers joist depths from 97mm to 235mm, spacing of 400mm to 600mm, and dead loads from not more than 0.25 kN/m² up to more than 0.50 but not more than 1.25 kN/m².
Table 4B.6 Maximum clear span of floor joists (m):
Timber strength class C24 C24
Size of joist (mm x mm) | Dead Load [kN/m²] excluding the self weight of the joist
Not more than 0.25 | More than 0.25 but not more than 0.50 | More than 0.50 but not more than 1.25
Spacing of joists (mm): 400, 450, 600 (repeated for each dead load category)
38 x 97: 1.94, 1.83, 1.59, 1.84, 1.74, 1.51, 1.64, 1.55, 1.36
38 x 120: 2.58, 2.48, 2.20, 2.47, 2.37, 2.08, 2.18, 2.07, 1.83
38 x 145: 3.10, 2.98, 2.71, 2.97, 2.85, 2.59, 2.67, 2.56, 2.31
38 x 170: 3.58, 3.44, 3.13, 3.43, 3.29, 2.99, 3.08, 2.96, 2.68
38 x 195: 4.10, 3.94, 3.58, 3.92, 3.77, 3.42, 3.53, 3.39, 3.07
38 x 220: 4.61, 4.44, 4.03, 4.41, 4.25, 3.86, 3.97, 3.82, 3.46
47 x 97: 2.14, 2.03, 1.76, 2.03, 1.92, 1.68, 1.80, 1.71, 1.50
47 x 120: 2.77, 2.66, 2.42, 2.65, 2.55, 2.29, 2.38, 2.27, 2.01
47 x 145: 3.33, 3.20, 2.91, 3.19, 3.06, 2.78, 2.87, 2.75, 2.50
47 x 170: 3.84, 3.69, 3.36, 3.67, 3.54, 3.21, 3.31, 3.18, 2.88
47 x 195: 4.39, 4.22, 3.85, 4.20, 4.05, 3.68, 3.79, 3.64, 3.30
47 x 220: 4.86, 4.73, 4.33, 4.71, 4.55, 4.14, 4.26, 4.10, 3.72
50 x 97: 2.20, 2.09, 1.82, 2.08, 1.98, 1.73, 1.84, 1.75, 1.54
50 x 120: 2.83, 2.72, 2.47, 2.71, 2.60, 2.36, 2.43, 2.33, 2.06
50 x 145: 3.39, 3.27, 2.97, 3.25, 3.13, 2.84, 2.93, 2.81, 2.55
50 x 170: 3.91, 3.77, 3.43, 3.75, 3.61, 3.28, 3.38, 3.25, 2.94
50 x 195: 4.47, 4.31, 3.92, 4.29, 4.13, 3.75, 3.86, 3.72, 3.37
50 x 220: 4.93, 4.80, 4.42, 4.78, 4.64, 4.23, 4.35, 4.18, 3.80
63 x 97: 2.43, 2.32, 2.03, 2.31, 2.19, 1.93, 2.03, 1.93, 1.71
63 x 120: 3.05, 2.93, 2.67, 2.92, 2.81, 2.55, 2.63, 2.53, 2.27
63 x 145: 3.67, 3.52, 3.21, 3.50, 3.37, 3.07, 3.16, 3.04, 2.76
63 x 170: 4.21, 4.06, 3.70, 4.04, 3.89, 3.54, 3.64, 3.51, 3.19
63 x 195: 4.77, 4.64, 4.23, 4.61, 4.45, 4.05, 4.17, 4.01, 3.65
63 x 220: 5.20, 5.06, 4.73, 5.05, 4.91, 4.56, 4.68, 4.51, 4.11
75 x 120: 3.22, 3.10, 2.83, 3.09, 2.97, 2.71, 2.78, 2.68, 2.43
75 x 145: 3.86, 3.72, 3.39, 3.70, 3.57, 3.25, 3.34, 3.22, 2.93
75 x 170: 4.45, 4.29, 3.91, 4.27, 4.11, 3.75, 3.86, 3.71, 3.38
75 x 195: 4.97, 4.83, 4.47, 4.82, 4.69, 4.29, 4.41, 4.25, 3.86
75 x 220: 5.42, 5.27, 4.93, 5.25, 5.11, 4.78, 4.88, 4.74, 4.35
38 x 140: 2.96, 2.84, 2.58, 2.83, 2.72, 2.47, 2.54, 2.44, 2.17
38 x 184: 3.87, 3.72, 3.38, 3.70, 3.56, 3.23, 3.33, 3.20, 2.90
38 x 235: 4.85, 4.71, 4.31, 4.70, 4.54, 4.12, 4.24, 4.08, 3.70
CLS/ALS
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