Code Of Practice On-Line

Code of Practice on-line

As the NZMRM updates its COP and prepares for a new version, a brief review of the past and current documents is presented by Stuart Hayman of the MRM Technical Committee.

The NZMRM Metal Roof and Wall Cladding of Practice is now available as a downloadable pdf from the NZMRM website, www.metalroofing. org,nz and has recently been updated to Version 2.2. It is intended to review the COP in 2013 as has been carried out at 5 year intervals, and it is possible that Version 3 will be
web-based rather than a document converted to a web document.

Watch this space.

In the meantime – some features of Version 2.2


The NZMRM Code of Practice has been through several publication methods in the 10 years it has been in existence. This reflects the changes in the building environment and available materials which seem to occur with increasing frequency as time goes on.

It is therefore perhaps worthwhile to trace in summary the history of this important source of information about metal cladding.

The NZMRM produced three earlier versions of the “NZ Metal Roofing Handbook” under a couple of names, starting in 1978 all written by Stuart Thomson. Following the publication in 2000 of the significant update (which of course is now the previous version) of NZS 3604, NZMRM realised the need to revise
these earlier books and also wanted to achieve greater recognition of our roofing knowledge database by the regulators.

At the time, the regulator was the Building Industry Authority (BIA) the very much smaller predecessor to the Department of Building and Housing (DBH) – which of course is just changing its name again, and becoming part of MBIE.

In those days it had 14 employees and talked to anyone. In July 2000 MRM asked for a meeting to discuss this matter and three of us (two from NZMRM and one from RANZ) met with BIA chairman Bill Porteous and his senior adviser Claire Benge to talk about our proposal to produce a completely new version of the
Handbook (not yet called the COP) and to ask about BIA recognition of such a document and some possible funding.

They were interested in the proposal and supported the idea. They were not however able to produce any funding because the Building Levy funds were not available for such purposes! BIA also told us that there was to be a major upgrade to E2/AS1 and that it would be useful for the two things to coincide – in a year or two.

History overtook the BIA with leaky buildings and E2/AS1 became a very large document produced with little industry input, by the quickly becoming 700 person DBH. The Metal Handbook became the NZMRM Code of Practice for Metal Roof and Wall Cladding and was produced by the NZMRM Technical Committee and published at great expense in 2003 – as a glossy, loose-leaf document in a hard cover. The quality was similar to that of NZS 3604:2000, at the time the biggest NZ Standard - and at a similar cost.

This cost proved to be a bit of a stumbling block as designers didn’t want to spend one hour’s chargeout rate to buy a copy. Eventually the hard copies were paid for by NZ Steel and distributed free.

But before that time, it was realised a more serious real issue with the hard copy was that it was difficult to search, and so it was converted into a very large, copy protected, pdf and put onto CDs which were then sold at a nominal cost.

This allowed users to copy it onto their own computers and use the search function of Adobe Acrobat Reader and its clones. This was undoubtedly a big leap forward (although hardly “cuttingedge” technology) and NZMRM still resisted people copying drawings or bits of text from it (which was not impossible, but difficult, and illegal). By 2007 the then version of E2/ AS1 (2004) was more or less accepted, and a number of technical changes had occurred within the industry. In addition, NZMRM and others had picked up a number of typos and actual errors in both the Code of Practice and E2/AS1. Stuart Thomson was engaged to produce Code of Practice Version 2, and this time the plan was to produce it only as a CD, with no hard copy, and make it more widely available. In 2008 the new version was published as a CD only and then later made available as a download from the NZMRM website – which had also been set up since 2003. This was still a pdf, but we now allowed copying drawings and print provided the source was acknowledged.

This was promoted by NZMRM widely to architects and designers and to Building Inspectors via BOINZ, and to anyone else we could and through Scope to our 11,000 readers.

It is pleasing to note that while at the 2009 BOINZ conference NZMRM participated in virtually noone had heard of the COP and we gave away very large numbers, by the 2012 conference everyone said they already had a copy, or it was on their network.

The COP has by now achieved wide recognition and acceptance by the building industry and regulators compared to its profile when first issued in 2003.

The technical committee realised during the period since 2008 that there were a number of amendments and updates that should be published before the development of Version 3.

Version 2.2

The existing pdf version had as its original a document written in a now-obsolete publishing programme and the entire 9 mb had to be converted into a newer system. Then the whole new version had to be amended in accordance with the Technical Committee’s changes and then converted into a searchable pdf with good internal links. (Some of these had been lost in the 2008 version).

This is now published and can be downloaded from the website, as Version 2.2. Where to find it

Go to

Click on the link and you go to the first page shown at the beginning of this article.

Some changes Navigation

We have improved navigation round the document in a number of ways – some old but improved and some new.

There are some new and some updated links. If a link is available, running your cursor over it changes to an arrow or pointing finger

1) Sidebar

In addition pages are now all numbered to aid going to places.

The normal Adobe Acrobat Reader (or similar – allow me to recommend Foxit Reader, less overhead and quicker) Search function works fine. The index pages, right at the beginning also contain clickable links. And we have re-introduced a feature not available since Version 1 – the linked diagrams

So, it is easier to find your way around, and like Microsoft, with several ways to do it. You will find a favourite way and use this.

2) Content

In the roofing world things do change and some of the original material is either now outdated or new developments have meant it could be reviewed and updated. There are heaps of changes or updates or new stuff. As you look for whatever interests you, you will find out if it has been changed. Changes
are marked in the margin with the date.

There is far too much to list in detail but some areas in which you will see important changes are –

  • Expansion allowance and provision – 4.1.6 – new diagrams and recommendations
  • Fastener durability – 7.8.3 et seq – reflects new products
  • Penetrations – where they are allowed and details of where to put them in the roof – Section 6 and drawings 6.2.6 a-d.
  • Safety Mesh – Section 14
  • Loadings – updated to align with NZS 3604 2011 – wind load, snow load in Section 3
  • Oversize holes have been defined properly – in definitions and to be applied everywhere they are mentioned.