new zealand metal roofing manufacturers inc. april 2012 nz metal roof and wall cladding de of practice table of ntents v:2.2 page 3 table of ntents 1 1.0 table of ntents 2.0p erformance 3.0 nstruction load 4.0.d esign 5.0f laHDPEngs 6.0p enetrations 7.0i nstallation 8.0 roof drainage 9.0 plastic roof lighting 10.0 pressed metal tiles