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Granny Flat Complying Development (CDC) – The Definitive Guide

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When planning to build a granny flat, you have two options for gaining approval. The easiest of which is through a CDC. So, firstly, what is a granny flat Complying Development (CDC)?


A Complying Development Certificate (CDC) is a way of gaining approval instead of submitting a Development Approval (DA). It is a faster and more straightforward process, as it was designed to bypass the Council, with the rules being the same over all of NSW. However there are rules that first must be met.


Today I will discuss what happens if you build a granny flat that does not abide by the CDC regulations. And I will explain exactly what the CDC is, and how this differs from a DA (Development Application).


DON'T PAY A FORTUNE FOR YOUR GRANNY FLAT. Find out how to deal with council and build a granny flat for the lowest cost possible. Learn More.

Plus cover what can go wrong if you build a granny flat that has not been approved.


Lastly, I will let you know what the difference is between getting a Council certifier and a private certifier for your CDC.


Do You Need a Permit for A Granny Flat?


In 2009, the NSW Government released the Affordable Housing State Environment Planning Policy (AHSEPP). This was an update from the State Environmental Planning Policy (SEPP). With this change came a new way of handling the Granny Flat applications.


Homeowners and investors wanting to build a granny flat were no longer required to obtain a Development Approval (DA), as long as;

  • Their applications meet the minimum Complying Development (CDC) requirements.


For more information, see the NSW Government Granny Flat Fact Sheet.


However, standard regulations include that your property be a minimum of 450 square metres with at least a 12m street frontage.


Zoning regulations also apply. Secondary dwellings are permitted in:


  • Zone R1 General Residential
  • Zone R2 Low Density Residential
  • Zone R3 Medium Density Residential
  • Zone R4 High Density Residential
  • Zone R5 Large Lot Residential (via DA only)
  • Or similar zones for your local Council region. A guide to these zones can be viewed here.


Unapproved Granny Flats – What Can Go Wrong


It is highly important that you get the relevant Council approval for your granny flat. You may find yourself in dire trouble if you do not take the time to gain approval.


If you build a granny flat that has not been approved by your local Council, they have the authority to:


  • Issue notice(s) that state you are required to do rectification work to make the granny flat compliant
  • If you fail to meet compliance, they can issue an order that the granny flat can be destroyed.


Unapproved granny flats, especially those not installed by qualified builders, are a serious health and safety concern.


Insurance companies will deny claims to unapproved secondary dwellings


Not to mention there is no way an insurance company will issue any payout if anything goes wrong with the Granny flat. This is because once an assessor comes over it will be deemed as being built illegally. Unfortunately this is enough for them to deny any payout


What Happens When You Build a Granny Flat Outside of the CDC Rules


The CDC is a fast way to get your granny flat approved, but it comes its’ with restrictions, which have absolutely no leniency.


Again, complying development (CDC) provisions can be seen here.


If you build a granny flat that does not abide by these regulations after gaining your CDC, you can:


  • Apply for Development Approval (DA) from your local Council. However, there is no guarantee this will be approved, and you may be asked to perform rectification works




  • As above, you will go under the regulations of an unapproved granny flat and potentially try through a DA to get the granny flat approved


So, it is best to abide by the rules of a CDC or you may face failure to meet compliance. With this comes the possibility that your development will be demolished if you break the strict CDC building rules.


What is a CDC? What is the Difference Between a CDC and a DA?


A Complying Development Certificate (CDC) is a way to accelerate the approval process for your granny flat. The rules for getting a CDC approved are the same throughout all of NSW, despite what local Council you reside in.


CDC was put in place by SEPP so low impact developments, such as granny flats, can avoid local Councils’.


This saves you both time and money.


Other benefits of a CDC include:

  • It is much faster and easier than applying for a DA, it can take only 10 days. (Where a DA can take weeks, perhaps months with some councils)
  • Applications can be submitted prior to registration of the land.


However, the disadvantages of the CDC are:

  • It has very clear and very firm rules that offer no leniency.


A Development Application (DA) is an application that is submitted to your local Council.


You must include a variety of information, including:


  • Drawings showing what the granny flat will look like when finished
  • The building materials that you are using
  • The impact you expect your development to have on the surrounding region
  • And much more.


Just exactly what paperwork you need to include depends on your local Council, so it is best you contact them for advice.


A DA comes with no guarantee of approval – it is in the hands of your local Council when they review your application.


Other downfalls of a DA include:


  • It takes much longer to get an answer – up to 3 months.
  • You can only submit your application after the land is registered.


However, a DA does have its’ benefits. These are:


  • The Council is less strict in certain areas of a DA than they are of the CDC
  • So, designs that do not comply with the CDC may possibly be approved through a DA.


To choose between a DA and CDC it is generally easier and cheaper to go the CDC route so check whether a CDC is allowed on your property first.


Some properties have restrictions that will only allow a DA. This information can be found on your 10.7 Planning Certificate.


This contains information on how your site may be developed and any restrictions on development.


Restrictions may include:


  • Hazard risk restrictions
  • Inclusion of critical habitat, conservation area or item of environmental heritage on land.


Landscaping Rules for a CDC?


The landscaping area that is required varies depending on the size of your property:


  • 450sqm – 600sqm = 20%
  • 600sqm – 900sqm = 25%
  • 900sqm – 1500sqm = 35%
  • 1500sqm or more = 45%


You will also need to check your granny flat complies with the guidelines of the estate in which you are building. New estates often have strict guidelines to ensure that the streetscape remains harmonious.


These include:

  • External colours
  • Materials used on the facade of the dwelling
  • Plants allowed in the garden


If you do not abide by these regulations, you could be building your granny flat outside the rules of your CDC.


Difference Between a Council Certifier and a Private Certifier for CDC’s


To gain approval for your CDC, you must either utilise either a Council certifier or an accredited private certifier. This is simply a ‘sign off’ from a building professional, or a certifying authority.


It is what allows you to bypass the need for a DA.


The difference between a Council certifier and a private certifier are:


  • A Council certifier may approve parts of your granny flat development that are DA elements. Meaning, these features do not comply with the SEPP, therefore do not comply with the CDC.
  • This may save you from having to get Development Approval (DA) later if you have not built your granny flat to the strict CDC rules.
  • A private certifier is fully compliant with SEPP, so will only approve your CDC if it abides by its’ firm regulations.


The cost for council certification is also cheaper, roughly $500+ while a private certifier is approximately $1600+


However, if you want to use a Council certifier, you must book them quite far in advance.




When you are looking to build a granny flat, you may have two options for getting your development approved. These are a Development Approval (DA) or Complying Development Certificate (CDC).


A DA is an application that you submit to your local Council, along with a variety of supporting technical reports and plans. A CDC was designed to bypass your local Council, and enable straightforward, fast-tracked approval processes.


Thus, the CDC can save you both time and money.


However, both have their benefits, and one option may be more suitable for you than the other, depending on;

  • The zone you are building in
  • The design you have in mind and the proposal you wish to make
  • Your timeframe


The CDC has very strict rules that offer absolutely no leniency. The DA, on the other hand, may allow you to bend the rules.


Designs that do not comply with the CDC may potentially be approved with a DA. But the DA takes much longer for approval than the CDC – the DA taking up to 3 months and the CDC taking 6-8 weeks.


There is also no guarantee for approval with a DA. As long as you are abiding by the regulations of SEPP, you are guaranteed approval with a CDC.


Whatever decision you make, it is important to get the relevant Council approval for your granny flat. The Council has the authority to make you do rectification work if you build an unapproved granny flat.


If you fail to meet this notice of compliance, they can issue an order to have the granny flat destroyed. So, if you don’t want to see your hard-work demolished before your eyes, ensure you gain the necessary approval.