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PATTERN RAFTER

PATTERN RAFTER. Roof plan. Pitch of roof Half span of roof Eaves overhang Rafter spacing Thickness – ridge hip rafters. = 22.5 ° = 2150mm = 300mm = 450mm = 25mm = 35mm = 45mm. Information required. Rise per metre =

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PATTERN RAFTER

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  1. PATTERN RAFTER

  2. Roof plan

  3. Pitch of roof Half span of roof Eaves overhang Rafter spacing Thickness – ridge hip rafters = 22.5° = 2150mm = 300mm = 450mm = 25mm = 35mm = 45mm Information required

  4. Rise per metre = rise/m = True length per metre = t.l./m = Set out length of rafter = set out length = Tan pitch angle 0.414 1.082 tl/m x half span 2.327m Calculations required

  5. Bevels required • 1. Plumb bevel rafter • 2. Level bevel rafter 1. Rise 2. Half span

  6. Steel square application 207 Rise/m ÷ 2 1000 ÷ 2 500

  7. Pattern rafter Set out length Halfspan

  8. Reduction : Common rafter Ridge Half thickness of ridge Half thickness ridge measured square to plumb bevel

  9. Reduction : Crown end Half rafter thickness Crown end Half rafter thickness measured square to plumb bevel

  10. Rafter spacing x tl/m ½ mitre thickness hip ½ rafter thickness = 0.450 x 1.082 = 0.487 = = 24.75mm = 22.5mm Creeper spacing calculations

  11. Crown end a Long point: first creeper c Creeper spacing b 487mm a a c b • c is long point • first creeper • Half mitre • thickness out • Half rafter • thickness back

  12. Continuous creeper spacing creeper spacing X tl/m 487mm 487mm long point first creeper 487mm 450mm 487mm 450mm overhang x tl/m 325mm 450mm 450mm 300mm

  13. Summary • Set out length and birdsmouth • Plumb bevel centre line • Reduction crown end • Reduction common rafter • Continuous creeper reduction • Long point 1st creeper • Square marks across top • edge and label • Eaves overhang • Mark edge bevel creeper

  14. Produced by : John Friedman jfriedman@tafensw.edu.au

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