A granny flat, also known as an ancillary dwelling, is a self-contained dwelling on the same site as another dwelling that may be attached to, integrated with, or detached from the primary dwelling.
What Is a Granny Flat?
A granny flat is the common term for an ancillary dwelling, a self-contained dwelling provided in association with another dwelling on the same site.
In Western Australia, the R-Codes use the term ancillary dwelling. The dwelling may be attached to, integrated with, or detached from the primary dwelling.
The term “granny flat” does not mean that the accommodation must be occupied by a grandparent or another family member. The applicable planning and building requirements determine whether the proposed dwelling can be developed on the site.
Granny Flats in Western Australia
Ancillary dwellings are subject to the Western Australian planning framework and the requirements that apply to the site.
The R-Codes provide development standards for ancillary dwellings, including requirements relating to floor area, parking, design, setbacks and other aspects of residential development.
Whether planning approval is required depends on the proposal and whether it satisfies the applicable planning requirements. Local government requirements and the planning framework applying to the property should be checked before work begins.
What Is an Ancillary Dwelling?
An ancillary dwelling is a self-contained dwelling associated with another dwelling on the same site.
It can be:
- attached to the primary dwelling
- integrated into the primary dwelling
- detached from the primary dwelling
The dwelling is intended to provide separate residential accommodation while remaining associated with the primary dwelling on the site.
Granny Flat Size Requirements
Under the current R-Codes deemed-to-comply provisions, an ancillary dwelling has a maximum internal floor area of 70 square metres.
The applicable requirements do not stop at floor area. Other planning and design provisions can also apply to matters such as parking, setbacks, building height, site coverage, privacy and open space.
A proposal that does not satisfy a deemed-to-comply provision may need to be considered through the applicable planning pathway rather than being assumed to comply automatically.
Granny Flats and Planning Approval
Whether a granny flat requires planning approval depends on the circumstances of the proposal and whether the applicable planning requirements are satisfied.
Where an ancillary dwelling satisfies the relevant requirements, it may be exempt from planning approval under the applicable planning framework.
However, planning exemption does not mean that the building can simply be constructed without further approval. A building permit may still be required before construction begins.
The applicable local government requirements should therefore be checked before proceeding with a project.
Granny Flats and Building Permits
A granny flat is building work and may require a building permit.
The building permit process is concerned with whether the proposed building work satisfies the applicable building legislation, codes and standards.
This is separate from determining whether planning approval is required.
The planning pathway and building approval pathway should therefore be considered separately when preparing documentation for an ancillary dwelling.
Who Can Live in a Granny Flat?
A granny flat is not limited to accommodation for grandparents.
An ancillary dwelling can provide separate residential accommodation, and the people who occupy it depend on the circumstances and applicable requirements.
The important distinction is between the common term “granny flat” and the planning term “ancillary dwelling”. The planning classification does not mean that the dwelling must be occupied by a particular family member.
Granny Flats and Building Design
Designing an ancillary dwelling requires consideration of the existing dwelling, the site and the requirements that apply to the proposed development.
Depending on the property and proposal, documentation may need to address matters such as:
- site layout
- setbacks
- building height
- access
- parking
- open space
- privacy
- building design
- relationship to the existing dwelling
Clear drawings help communicate how the proposed ancillary dwelling fits within the site and responds to the applicable requirements.
Granny Flats and the R-Codes
The R-Codes are particularly relevant to the planning and design of residential development in Western Australia.
For an ancillary dwelling, the applicable R-Code provisions can affect matters including floor area, parking and the relationship between the new dwelling and the existing development.
Where a proposal departs from a deemed-to-comply provision, the appropriate planning pathway and justification requirements need to be considered.
Kyle Standing’s Perspective on Granny Flats
Kyle Standing’s engineering and drafting background provides context for the role of building documentation in residential projects.
For an ancillary dwelling, accurate drawings need to communicate the proposed building clearly and show how it relates to the existing dwelling and site.
Good documentation can help identify planning and building requirements early and provide the information needed for the relevant approval processes.
Related Terms
Granny flats are closely connected with several terms used throughout the residential building and approval process:
- Building Designer
- Draftsman
- Building Surveyor
- Building Permit
- Development Application
- R-Codes
- National Construction Code