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Purlin-Rafter Connections

For sprung curved roofs, the purlin/rafter connection must be increased at the eaves.

Long lengths of pierce fixed roofing will impose added loads to the purlin connection due to thermal movement of the roof.

Purlin to rafter fastener requirements for SG8 Radiata pine, complying with NZS 3604:2011

 Use 70 x 45 mm radiata pine on flat minimum
 Use 90 x 45 mm radiata pine on flat minimum
Rafter SpacingPurlin SpacingLow Wind ZoneMedium Wind ZoneHigh Wind ZoneVery High Wind ZoneExtra High Wind Zone
0.90.6ABCCC
0.90.9BCCCD
0.91.2CCCDD
1.20.6BCCCC
1.20.9CCCDD
1.21.2CCDN/AN/A
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Purlin to Rafter Fastener Fixing Capacity

TypeFastenerFixing Capacity (kN)
A1/90 x 3.15 gun nails0.55
B2/90 x 3.15 gun nails0.80
C1/10g x 80 mm self-drilling screw2.40
D2.10g x 80 mm self-drlling screws3.45
E1/14 g X 100 mm self-driling screws5.50
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/cop/structure/maximum-span-and-fastener-requirements#purlin-rafter-connections
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