For a fuller explanation of this refer to the nz metal roof and wall cladding code of practice.
Roof purlin nz.
The purlin spacings should be limited to the lower of the trafficable limitations and design wind load with the capacity of the structure.
The vb20 is designed with 4mm evenly spaced openings specifically sized to prohibit large insects gaining access but wide enough to prevent capillary action.
The vent vented batten is a strong durable purlin cavity batten that is designed to ensure that unimpeded airflow is guaranteed through the roof cavity of a skillion roof design enabling passive airflow around the entire building envelope.
Metalcraft roofing s structural division manufactures metalcraft super span shortened to mss purlins and girts for the new zealand construction market and the pre engineered garages and sheds market segment.
This result should be referenced to the wind load span design graphs.
New zealand metal roofing manufacturers inc.
Ms tophats are cut to length and available in a range of sizes and gauges to suit a variety of applications.
Speed of installation is assured as dhs purlins and girts are supplied complete with brace channels ready for site assembly.
The dimond structural dhs purlin range is available in 12 sizes from dhs 150 12 to dhs 400 20 to suit commercial applications from 5m to 18m spans.
Mss purlins and girts are available in a variety of sizes and gauges cut to length and prepunched to suit a variety of applications.
Top notch purlins come in a full range of sizes from 60mm to 150mm depth easily tek screwed to the supports without the need for purlin bracing and cleats.
They are ready for use in many smaller spanning applications from 2m to 7m.
Www miteknz co nz copi 2020 mit holis i all is s ma 2020 purlin batten fixing chart fixing type e 5 5kn 2 nails plus 1 ct200 or 1 pair of cpc40 cpc40 cpc40 purlin batten purlin batten fixing type d 3 45kn 2 blue screws or 2 skew nails plus 2 wire dogs for purlin on edge fixing type c 2 4kn purlin batten 1 blue screw 2 nails fixing.
The introduction of nzs 3604 in 1978 gave specific requirements for rafter purlin and ceiling joist sizes and spacing.
Purlin splice 90 x 35mm block fixed to chord or rafter with 4 x 75mm nails cpc40 cpc40 type c 1 screw to each purlin type d e 1 nail plus 1 screw to each purlin ct200 lumberlok ceiling tie ct200 bend over purlin 4 x lumberlok product nails purlin batten gang nail lumberlok bowmac www miteknz co nz mitek new zealand limited.
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.