Purlin Spacing For Metal Roofing Nz

It often depends on the wideness thickness and the types of roofing materials the climate it has to withstand and many other factors.

Purlin spacing for metal roofing nz.

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. 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. 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. The adjustable cleat can be rotated up to 15 degrees from normal to accommodate the change in angle from vertical portal to the roof slope of the rafter.

For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap. Purlins up to 1200mm spacing must be fixed with a 1 10g 80mm long purlin screw minimum or a pryda purlin strap bs 70. The introduction of nzs 3604 in 1978 gave specific requirements for rafter purlin and ceiling joist sizes and spacing. See section on purlin girt spacing.

For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet. End purlins and periphery of roof to be fixed every 2nd crest. End purlins and periphery of roof to be fixed every 2nd crest. C3 fix side laps and miss 2 hit 1 miss 3 hit 1 miss 2 etc with approved fasteners alone.