Technical Booklet D Structure·Page 46·Table 4B.29
Table 4B.29: Maximum clear span of rafters for roof pitch 30° to 45°
This table provides maximum clear spans in metres for timber rafters of various sizes and spacings, for roofs pitched between 30° and 45° with an imposed load of 0.75 kN/m² and timber strength class C24. Dead loads exclude the rafter's self-weight.
Table 4B.29 Maximum clear span of rafters (m); Roof pitch more than 30° but not more than 45°; Imposed load 0.75 kN/m²; Timber strength class C24 C24
Dead Load [kN/m²] excluding the self weight of the rafter
Size of rafter (mm): Dead load 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 for each dead load category
38 x 100: 2.56, 2.47, 2.24 / 2.40, 2.31, 2.10 / 2.28, 2.19, 1.99
38 x 125: 3.19, 3.07, 2.80 / 2.99, 2.88, 2.62 / 2.84, 2.73, 2.48
38 x 150: 3.81, 3.67, 3.35 / 3.58, 3.45, 3.14 / 3.39, 3.27, 2.97
47 x 100: 2.74, 2.64, 2.41 / 2.58, 2.48, 2.25 / 2.44, 2.35, 2.13
47 x 125: 3.41, 3.29, 3.00 / 3.21, 3.09, 2.81 / 3.04, 2.93, 2.66
47 x 150: 4.08, 3.93, 3.59 / 3.83, 3.69, 3.36 / 3.64, 3.50, 3.19
50 x 100: 2.80, 2.70, 2.45 / 2.63, 2.53, 2.30 / 2.49, 2.40, 2.18
50 x 125: 3.48, 3.35, 3.06 / 3.27, 3.15, 2.87 / 3.10, 2.99, 2.72
50 x 150: 4.16, 4.01, 3.66 / 3.91, 3.77, 3.43 / 3.71, 3.57, 3.25
38 x 89: 2.28, 2.20, 2.00 / 2.14, 2.06, 1.87 / 2.03, 1.95, 1.77
38 x 140: 3.56, 3.43, 3.13 / 3.35, 3.22, 2.93 / 3.17, 3.05, 2.77
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