Complying development certificate for dwelling found invalid for lack of retaining wall certification

The Building Professionals Board (‘BPB‘) recently investigated a complying development certificate (‘CDC‘) issued by an accredited certifier for the erection of a dwelling.  The CDC was issued without an engineer’s certificate for a retaining wall to support the excavation for the concrete slab. The BPB concluded that the CDC was issued inappropriately as the development did not comply with the relevant prescribed development standards in that regard.

Complying Development

Complying development is development that can be addressed by predetermined development standards and that can be carried out with consent in the form of a CDC under Division 4.5 of Part 4 of the Environmental Planning and Assessment Act (‘EPA Act‘) and Part 7 of the Environmental Planning and Assessment Regulation 2000 (‘EPA Reg‘) .

A council or certifier must evaluate whether the proposed development is complying development and whether it complies with the relevant development standards (s 4.28(3) EPA Act).

The erection of the dwelling house for which the CDC was granted could have been complying development if it met the requirements for complying development and the development standards prescribed by the Housing Code in Part 3 of State Environmental Planning Policy (Exempt and Complying Development Codes) 2008) (the ‘Housing Code‘).

The Development Standards

The prescribed development standards include development standards for earthworks, retaining walls and structural support (Cl 3.30 of the Housing Code) and require that a professional engineer must certify, as structurally sound, a retaining wall or other structural support  for earthworks more than 600 mm below ground level (cl 3.30(7)(a) of the Housing Code)


In the case of the subject CDC, the site plan for the proposed development noted that a retaining wall was needed to support the excavation for the dwelling’s concrete slab. However, the certifier issued the CDC without sighting an engineer’s certificate for the retaining wall. The certifier argued that the CDC was issued only for the dwelling and didn’t include the excavation outside the building envelope.

The BPB disagreed with the certifier for the following reasons:

  • The development standards for the development included the excavation for the dwelling not just the erection of the dwelling;
  • The approved plans incorporated the retaining wall and, to be complying development, the retaining walls had to be certified by an engineer; and
  • It was inappropriate for the certifier to treat the application for the CDC as limited to the building envelope.

The BPB took the view that a person relying on the CDC could consider that the earthworks were approved by the CDC. The BPB’s reasons can be found here.

Powers of councils, certifiers and the court

A council or a certifier can require the applicant for a CDC to give the certifier any additional information concerning the proposed development from a properly qualified person that is essential to the certifier’s proper consideration of an application for a CDC (cl 127 EPA Reg).

If the applicant fails to provide essential information such as an engineer’s certificate for a retaining wall or other structural support the council or the certifier must determine the application by refusing to issue the CDC (s 4.28 (6) EPA Act).

The Land and Environment Court has power to declare that a CDC is invalid if the CDC authorises the carrying out of development for which the Court determines that the CDC was not authorised to be issued (ss 4.31 and 9.46(1) EPA Act).


Councils and certifiers should be careful to ensure that applications for CDC’s for proposed development include sufficient information for the council or certifier to determine whether the proposed development complies with the development standards for associated works. If the application does not include appropriate certification from a properly qualified person, the council or certifier should require the applicant to provide that information. If the applicant does not provide the information, the council or the certifier should refuse to issue the CDC.

To discuss this post please contact Frances Richards on 02 8235 9707 or Stuart Simington on 02 8235 9704.


About frances richards

frances richards. special counsel. Frances has practiced as a specialist local government, planning and environmental lawyer for over 15 years. Frances has worked in-house in local government and in private legal practice in Australia and the UK during her career, including 10 years as a partner in a national law firm. Frances has conducted training seminars for local government and private clients on the regulatory and enforcement functions of local government and risk management. Frances has acted for local and state governments, local government entities, statutory corporations and private developers. Frances has conducted litigation for clients in the Local Court, Land and Environment Court, Supreme Court and Court of Appeal in NSW. Frances authored a report to the state government on the national regulation of the aquaculture industry. Frances has particular experience advising local government clients relating to the provision of waste management services and infrastructure including the procurement of services and infrastructure. Frances has investigated and authored reports on complaints about conduct and reviewed governance, probity and compliance frameworks for local government clients.
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3 Responses to Complying development certificate for dwelling found invalid for lack of retaining wall certification

  1. Anthony Newland says:

    Dear Frances

    On the issue of splitting a CDC into a number of parts, a certifier I am dealing with recently took an interesting approach to a fire rebuild of a dwelling costed at $278,000 (genuine cost). The work was not exempt development due to structural timbers being required (but was complying development), however the certifier issued a CDC for structural work costed at $46,000 and stated the rest of the work was exempt development. It is not appropriate to split the rebuild into two categories, or is it?

  2. sam robins says:

    Dear Frances
    I have struggled to understand this issue for a number of years now and have not had a suitable response from the department (have tried a number of times). the issue we have in wagga is that private certifiers often issues CDC’s based on plans that show compliance with the standards. once excavation starts, slab, frame etc they then ‘notice’ that the site cut does not comply. Council then receive a DA for just the site cut and retaining wall. if you are a glass half empty type of guy like me you assume that both the builder and private certifier knew this was the case all along and simply wanted to get the house through and going and deal with the cut and retaining wall issue later.
    my question for the department that i never got answered was does this make the whole CDC invalid? as it was never possible to build the house as a CDC in the first place.
    it seems like a flawed system if you can lodge plans to get something through as a CDC and then just lodge DA’s for the parts of it that dont comply once you start building.


    • frances richards says:

      Dear Sam
      Thank you for your question regarding whether a CDC for building a house can be validly issued if the excavation and retaining walls do not meet the development standards for complying development and subsequently require a DA for the excavation and the retaining walls.
      We can only give a response that is general in nature as we do not know the location of the land, we have not seen the application for the CDC and we do not know which EPI was relied on by the application as specifying the house as complying development.
      In our view a certifier cannot consider and determine whether or not the proposed development for a house is complying development and complies with all of the relevant development standards without requiring information about the associated works and considering whether the associated works comply with any development standards for the associated works under the relevant EPI. A CDC is a certificate that states that particular proposed development is complying development and (if carried out as specified in the certificate) will comply with all development standards applicable to the development and with the other requirements of the regulations (s 4.27 EPA Act). The certifier must refuse to issue a CDC for a house if the excavation and retaining walls for the house do not meet the complying development standards for the associated works in the EPI (s 4.28(6) EPA Act).
      Regards, Frances