Purlin Spacing For Metal Roofing Nz

Where the end purlin spacing is less than 800mm an adjustable end brace with a bolted end cleat is available as twisting of the end cleat is not practical.

Purlin spacing for metal roofing nz.

For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet. The introduction of nzs 3604 in 1978 gave specific requirements for rafter purlin and ceiling joist sizes and spacing. End purlins and periphery of roof to be fixed every 2nd crest. For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap.

End purlins and periphery of roof to be fixed every 2nd crest. 1 2 it should be noted that timber purlins for metal roof cladding are minimum 70mm x 45mm h1 2 18 moisture content and that battens used previously for tiles must not be used. C3 fix side laps and miss 2 hit 1 miss 3 hit 1 miss 2 etc with approved fasteners alone. On site framing of gabled roofs generally used couple close construction that is where each pair of rafters are tied at their bases by ceiling joists to prevent spreading.

When the purlin spacing is close to the maximum allowable for the profile and ease of curvature the roof cladding is more likely to be damaged by foot traffic and distortion between the purlins. Purlins up to 1200mm spacing must be fixed with a 1 10g 80mm long purlin screw minimum or a pryda purlin strap bs 70. When the radius of curvature is close to the minimum the purlin spacing should be reduced to the end span distance for each gauge and profile. See section on purlin girt spacing.