Posted on November 28, 2018 by Stuart Simington and

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 Stuart Simington on 02 8235 9704.