Technical Booklet D Structure·Page 43·Table 4B.23
Table 4B.23 Maximum clear span of rafters
Table providing maximum clear spans in metres for timber rafters with C16 strength class, roof pitch between 22.5° and 30°, and 1.00 kN/m² imposed load. Spans vary by rafter size, spacing, and dead load category.
Table 4B.23 Maximum clear span of rafters (m); Roof pitch more than 22.5° but not more than 30°; Imposed load 1.00 kN/m2; Timber strength class C16
Dead Load [kN/m2] excluding the self weight of the rafter
Size of rafter (mm): 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
38 x 100: 2.18, 2.13, 1.96, 2.01, 1.96, 1.82, 1.88, 1.82, 1.68
38 x 125: 2.80, 2.69, 2.45, 2.65, 2.55, 2.30, 2.53, 2.44, 2.15
38 x 150: 3.35, 3.22, 2.93, 3.18, 3.06, 2.73, 3.03, 2.92, 2.55
47 x 100: 2.41, 2.32, 2.11, 2.28, 2.20, 2.00, 2.18, 2.10, 1.90
47 x 125: 3.00, 2.89, 2.63, 2.85, 2.74, 2.49, 2.72, 2.62, 2.37
47 x 150: 3.59, 3.46, 3.14, 3.41, 3.28, 2.98, 3.25, 3.13, 2.83
50 x 100: 2.46, 2.37, 2.15, 2.33, 2.24, 2.04, 2.23, 2.14, 1.94
50 x 125: 3.06, 2.95, 2.68, 2.91, 2.80, 2.54, 2.78, 2.67, 2.43
50 x 150: 3.66, 3.52, 3.21, 3.48, 3.34, 3.04, 3.32, 3.20, 2.90
38 x 89: 1.82, 1.79, 1.69, 1.69, 1.65, 1.55, 1.59, 1.55, 1.44
38 x 140: 3.13, 3.01, 2.74, 2.97, 2.85, 2.56, 2.83, 2.72, 2.29
CLS/ALS
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