Technical Booklet D Structure·Page 48·Table 4B.33
Table 4B.33: Maximum clear span of rafters for pitched roofs
This table provides maximum clear span values in metres for rafters with roof pitch between 30° and 45°, imposed load of 1.00 kN/m², and timber strength class C24, organized by rafter size, spacing, and dead load range.
Table 4B.33 Maximum clear span of rafters (m); Roof pitch more than 30° but not more than 45°; Imposed load 1.00 kN/m2; Timber strength class C24 excluding the self weight of the rafter
Not more than 0.50, More than 0.50 but not more than 0.75, More than 0.75 but not more than 1.00
Spacing of rafters (mm): 400, 450, 600 (repeated for each dead load range)
38 x 100: 2.42, 2.33, 2.12, 2.29, 2.20, 2.00, 2.18, 2.10, 1.90
38 x 125: 3.02, 2.90, 2.64, 2.86, 2.75, 2.50, 2.72, 2.62, 2.38
38 x 150: 3.61, 3.47, 3.16, 3.42, 3.29, 2.99, 3.26, 3.14, 2.85
47 x 100: 2.60, 2.50, 2.27, 2.46, 2.36, 2.15, 2.34, 2.25, 2.05
47 x 125: 3.23, 3.11, 2.83, 3.06, 2.95, 2.68, 2.92, 2.81, 2.55
47 x 150: 3.86, 3.72, 3.39, 3.66, 3.52, 3.21, 3.49, 3.36, 3.06
50 x 100: 2.65, 2.55, 2.32, 2.51, 2.41, 2.19, 2.39, 2.30, 2.09
50 x 125: 3.30, 3.17, 2.89, 3.12, 3.01, 2.73, 2.98, 2.87, 2.61
50 x 150: 3.94, 3.79, 3.46, 3.73, 3.60, 3.27, 3.57, 3.43, 3.12
38 x 89 (CLS/ALS): 2.16, 2.08, 1.89, 2.04, 1.96, 1.78, 1.95, 1.87, 1.70
38 x 140 (CLS/ALS): 3.37, 3.25, 2.95, 3.19, 3.07, 2.79, 3.05, 2.93, 2.66
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