What is the Performance Requirement for metal studs and girts?

The Performance Requirements for metal stud walls and girts differ between residential buildings and non-residential buildings.

For residential buildings, NCC requires you to add no less that R0.2 thermal break to be installed at all points of contact between the external cladding and the metal frame. This is the case even if you are following the Verification Method for energy efficiency compliance instead of Deemed to Satisfy pathway [1]

For non-residential building, you need to calculate the effective Total R-value that includes the negative impact of thermal bridging. The effective Total R-value must be not less than the required Total R-value and if it is, you need to tackle the problem by adding air gaps and thermal breaks.