Does F3D5(c), by reference to AS 1562.1, preclude the use of panel-style metal wall cladding that does not meet this standard? The short answer is ‘no’. In those circumstances there is another method of demonstrating NCC compliance.
The 15-second summary
Some practitioners and suppliers have asked whether the new Volume One provision F3D5(c) effectively prohibits the use of panel-style wall cladding, including laminated panels that do not meet AS 1562.1. While the answer is ‘no’, there is also another method of demonstrating NCC compliance that will be more suitable.
F3D5(c) introduces a new method of demonstrating compliance but does not preclude or invalidate the use of other methods, including those used prior to the introduction of this new provision.
Background
The National Construction Code (NCC) contains a Performance Requirement, F3P1 (2019: FP1.4), that requires, in part, that an external wall of a Class 2-9 building must prevent the penetration of water to protect the building and its occupants.
NCC 2019 Volume One Amendment 1 and previous editions include a note indicating that there are no Deemed-to-Satisfy (DTS) Provisions in respect of external walls for FP1.4. Therefore, in this circumstance, a Performance Solution is necessary to demonstrate compliance of a Class 2-9 building’s external wall cladding system with FP1.4.
Conversely, since inception, NCC Volume Two has included DTS Provisions for demonstrating the weatherproofing performance of some traditional external wall cladding systems for Class 1 and 10 buildings. Among these provisions is H1D7(5) (2019: 3.5.5.0) for metal wall cladding. This provision was introduced in NCC 2011 to provide a weatherproofing DTS compliance pathway for the use of solid metal sheeting for wall cladding in Class 1 and 10 buildings. H1D7(5) indicates that compliance with the relevant Performance Requirement is achieved when a solid metal wall cladding system complies with AS 1562.1 Design and installation of sheet roof and wall cladding: Metal. The standard does not apply to composite or laminated metal wall systems.
NCC 2022
NCC 2022 includes a new provision for Volume One, F3D5, that introduces DTS Provisions for demonstrating compliance with F3P1 for certain wall cladding types. Among these is F3D5(c), that provides a DTS compliance pathway for solid metal sheeting in the same manner that H1D7(5) does for Volume Two.
F3D5(c) and metal wall cladding panel systems
It is common for wall cladding systems for Class 2-9 buildings to incorporate solid metal panels, laminated metal panels or composite metal panels. AS 1562.1 applies to solid metal cladding, therefore this standard may be considered as a DTS compliance pathway for solid metal wall cladding panel systems. However, on account of AS 1562.1 being developed primarily for solid metal sheet roof and wall cladding, many other metal wall cladding panel systems will not meet the requirements of AS 1562.1. For example, a laminated or composite cladding panel’s base metal thickness may not meet the minimum dimension specified in AS 1562.1.
F3D5(c) does not prohibit the use of metal wall panel cladding systems that do not comply with AS 1562.1. In the absence of suitable DTS Provisions, such systems should have their compliance with F3P1 demonstrated by way of a Performance Solution. This is not new, having been the case under NCC 2019 Amendment 1 and previous editions.
A CodeMark Certificate of Conformity that attests compliance with F3P1 for a metal wall cladding panel system is one example of a Performance Solution described above.