Why Using Our Clips Will Ensure You Are NCC Compliant
Currently, in the Australian cladding and roofing industry, it is standard practice for most installers to use stainless steel clips to install all types of metal cladding, including Colorbond®, zinc, etc.
What most installers don’t know is that by doing so, they are in breach of the regulations stated in the National Construction Code (NCC) and Standards Australia (AS 1562.2) outlining the acceptability of direct contact between metals or alloys.
These regulations are detailed and, at times, complicated, so we have compiled all the necessary information in this article to help you understand exactly what you need to do to ensure your cladding and roofing is compliant.
So, what exactly does the NCC specify about the contact and compatibility of metals and alloys? There are two sections in the NCC 2019 containing this information. They can both be found in Volume Two; the first is found on page 178 under the title of “Roof and Wall Cladding” section “3.5.1.1 Acceptable corrosion protection for metal sheet roofing” and classifies the four types of environments in which the corrosion of steel occurs and the corrosion severity.
Environment 1: Low (L)
Remote inland area, more than 1km from sheltered bays.
e.g. dry rural areas, remote from coast or sources of pollution, most areas of Australia at least 50km from the sea, Canberra, Ballarat, Toowoomba, Alice Springs, some suburbs of Melbourne, Hobart, Brisbane and Adelaide that are more than 1km from the sea. Many of these do, however, have exceptions.
Environment 2: Medium (M)
More than 1km from breaking surf and/or aggressive industrial areas. More than 50km from sheltered bays.
e.g. Urban inland, coastal areas with low salinity, Port Phillip Bay, 50m from shoreline to distance of 1km inland but extends to 3 to 6km seasonally, ocean fronts with breaking surf and salt spray, much of Wollongong, Sydney, Newcastle, Perth, Gold Coast, urban and industrial areas with low pollution, several kilometres around steel works and smelters.
Environment 3: High (H)
More than 200m from breaking surf and/or aggressive industrial areas or within 50m from sheltered bays.
e.g. Coast around sheltered bays, extends from up to 50m from shoreline, areas of rough seas and surf to about 1km inland, inside industrial plants, locations 1.5km down wind of a plant.
Environment 4: Very High (VH)
Up to 200m inland from breaking surf and/or within 200m aggressive industrial areas.
e.g. Beachfronts, areas of rough seas and surf beaches, extends several hundred metres inland, aggressive industrial areas with pH of less than 5.
These classifications are important to understand as they are used in the table below that specifies the acceptability of contact between different roofing materials.
As specified in the table, stainless steel fasteners are only acceptable to use for installation with steel, zinc and copper products when being used in an environment classified as “low”; the yellow section of the table details that in a “medium”, “high”, or “very high” environment stainless steel clips cannot be used to install steel materials. Instead, Zinc-coated steel and zinc or Zinc/aluminium coated steel or aluminium/zinc and aluminium/zinc/magnesium coated steel must be used in these environments, as indicated by the green section.
The second section in the NCC 2019 containing information regarding the contact and compatibility of metals and alloys is “part 3.5.5 Metal wall cladding”. This section is small as it refers to the document AS 1562.1 for installation guidelines. It states “performance requirements are satisfied for a metal wall cladding if it is designed and constructed in accordance with AS 1562.1” This document created by Standards Australia has much of the same information as the NCC table above, however, below are the regulations from AS 1562.1 regarding “acceptability of direct contact between metals or alloys” to ensure you are aware and can meet the necessary requirements for your wall cladding according to the NCC and AS 1562.1.
Environment classifications
SI: Severe industrial
VS: Very severe
Mild: Mild classification
As you will notice, the information in this table is very similar to the NCC but there are a few variances so it is important to take note of the yellow and green sections highlighting when stainless steel fasteners can be used to install steel materials and zinc materials and when they cannot.
If you have any questions in relation to this article, do not hesitate to contact us.
