All government and council approval authorities must ensure that any new or refurbished building, or part of the building, complies with the design and construction requirements nominated under the BCA. These requirements form the base approval regime Australia wide.

Australian Standards are part of the BCA as well but generally the BCA takes precedence as the guiding framework while quite often deferring to the relevant Australian Standard as a compliance guideline. All building designs and therefore the built components of the design have to ensure that they comply with all relevant BCA requirements.

The BCA is a prescriptive requirement only and therefore is quite flexible.

The basic framework outlined within the BCA allows for acceptance of alternative design and build solutions. These alternative solutions must comply with the overarching performance requirements spelt out by BCA but can address the issue or solve the problem encountered during the design or building process in a number of different ways.

The BCA in many cases is also open to interpretation.

The code is updated every year and in 2006 a raft of energy efficiency requirements were implemented into the BCA. These requirements, known as Section J (named after the relevant section in the BCA on Energy Efficiency) have raised the level of energy efficiency in all buildings throughout Australia. Although every state and territory must comply with the BCA requirements there are certain state and territory exemptions and dispensations that are found in the BCA relevant to those particular states. Most of these are found in the residential section of the BCA and the one that is most well known is BASIX.

BASIX is a NSW Government initiative designed to improve the efficiencies of a residence over and above that required by Section J.

BASIX is an acronym for Building Sustainability Index. It was introduced before the introduction of the Section J efficiency requirements so it can claim to be the first real mandatory measurable energy efficiency standard for homes in Australia. It deals with three specific areas of efficiency:-

1. Energy efficiency
2. Water efficiency
3. Thermal comfort

It is a web based tool for all home owners and designers to access .Through the use of the tool it is possible to create a list of efficiency requirements for your home relevant to the actual climate zone in which the home is located. This ensures that the house designed for The Alpine region, for instance, has different design protocols for the house designed for the North Coast of NSW which has a more temperate climate.

Once you have completed all the relevant requirements under BASIX using the web based tool and your building design complies with the efficiency levels stipulated for that type of home in that specific area, a certificate of compliance is issued. Once you print this out you must then produce that certificate to the approval authority such as Council or Private Certifying Authority (PCA) to gain your construction certificate.

You cannot commence works with out that construction certificate and it wont be issued unless you have complied with the BASIX design requirements and can produce the appropriate certificate that certifies your proposed homes compliance.

In other states a more simple check list is issued which ensures similar residential efficiency compliance. If you feel it is too difficult to ensure your home complies with BASIX or you would like to make your home even more efficient or even validate the interpretations you have gained from BASIX, you can use an accredited assessor who can undertake a thermal assessment of your home design and provide a certificate certifying that your home has achieved the required thermal comfort and energy efficiency ratings stipulated under the BCA. These professional assessors use leading edge thermal analysis software. They are trained in thermal building assessments while also being accredited to issue the thermal and energy components of the BASIX compliance certificate.

While all states vary slightly in their approval requirements, outside of NSW there is a minimum energy and water consumption requirement graded by a star rating that all homes must comply with. In NSW, BASIX sets actual numerical consumption targets your home must comply with.

The overall intent of BASIX is that your home will use 40% less energy and water than a similar home that doesnt meet all of the BASIX requirements.