Sweeping changes

There have three significant moments in time for Australia’s National Construction Code, formerly the Building Code of Australia (BCA). These were:

• 1988: the first edition of the consolidated Building Code of Australia (BCA) encompassing nationally consistent technical building requirements
  
• BCA 1996:
  
• The first edition of the BCA being a performance-based code offering both prescriptive Deemed-to-Satisfy Solutions and Performance (Alternative) Solutions to demonstrate compliance
• The full first edition of BCA Volume Two the ‘Housing Provisions’ providing a dedicated stand-alone code for houses, garages and other low-rise buildings and structures.
• 2011: the first edition of the National Construction Code encompassing both building and plumbing incorporating the Plumbing Code of Australia.

NCC 2022 will be the next and arguably the most significant amendment to the national building code since its inception. 

All in all NCC 2022 is shaping as the largest single amendments of any past amendments both in terms of the volume of changes and the scope and impact of the proposed reforms, particularly for houses and low-rise apartments. 

Whole of house approach to energy efficiency

In February 2019 the COAG Energy Council (State and Territory Energy Ministers) met and agreed on a forward program for increases to the NCC energy-efficiency provisions over the next decade and beyond. 

For Class 1 buildings and Class 2 buildings, the agreed trajectory recommends significant stringency increases for NCC 2022 and NCC 2025 and thereafter more gradual increases every three years until a target of ‘zero energy (and carbon) ready buildings’ is achieved. 
The proposed NCC 2022 changes includes:

For Class 1 buildings

• Requiring the building fabric to be set at 7 stars
  
• A significant re-write of the DTS provisions of Part 3.12, set at a 7-star equivalence
  
• Introducing new requirements for thermal bridging of steel framing
  
• New whole of house provisions for determining the building services and required size of PV required for the building – likely to be a new ABCB calculator
  
• Revising the verification using reference building method
  
• Developing a new quantified Performance Requirement (based on a societal cost of energy metric).

The concurrent work being undertaking on upgrading the star rating tools (Accurate, first rate5, BERS Pro and HERO) to be set at 7 star and to be whole of house rating tools.

Currently the star rating tools only assess the building fabric. They are also likely to be expanded to include other rating tools including BASIX in NSW and potentially the Net Zero Carbon tool recently developed in Victoria.

For Class 2 buildings and Class 4 parts of a building

• Under star rating approach, it will require 7-star average approach across the apartment building with no apartment permitted to be less than 6-stars (under NCC 2019 it is set at 6-star average and no apartment less than 5-star)
  
• Developing new elemental DTS provisions for Class 2 buildings set at 7-star equivalence
  
• Developing a new verification using reference building method for Class 2 buildings
  
• Introducing new requirements for thermal bridging of steel framing.

Given the scope of these changes and their complex nature, they will be released for consultation separate to the remainder of the NCC in mid-July for an eight-week consultation period. The condensation provisions will also be released for consultation at this time. 

HIA will convene some workshops in late July to further discuss and break down these changes.

Current state variations to the national energy-efficiency provisions will be considered alongside the decision on the final NCC provisions, and there will be separate consultation on BASIX changes in NSW.

Breathing buildings

The issue of condensation in buildings and how the NCC should deal with the risk has been on the ABCB work program since 2014. The issue emerged in the colder climates of Australia but concerns have also been raised in warmer and humid climates.

With the energy-efficiency provisions in the NCC ramping up and buildings being more tightly sealed with less ability to breathe, condensation has become a real concern. 

NCC 2019 introduced requirements for vapour permeable membranes in certain climates, mandatory ducting and/or roof space ventilation and a new condensation risk management Verification Method.

For NCC 2022 more substantive measures are being proposed including:

• Reviewing the NCC 2019 provisions
  
• Updating Australian Standards
  
• Changes to wall sarking requirements to more vapour permeable type equivalent to Class 3 or Class 4 membrane
  
• Ventilation roof spaces – including air spaces for roofs and under roof insulation and roof sarking not to ‘saturate’ roof and either whirly birds, ridge or eave vents. 
  
• More substantive and targeted education material particular
  
• Exhaust systems changes including:
  
• Minimum flow rate for exhaust fans
  
• Mandatory exhaust and ducting for rangehoods
  
• No recirculating rangehoods permitted
  
• Bathrooms not naturally ventilated have exhausts with 10-minute run-off timer.