Alterations and extensions

This guide helps you determine which permits and approvals you need to alter or extend a house that is the only dwelling on a lot (a single dwelling).

  • ‘Alteration’ means making an internal or external change to an existing dwelling without increasing the floor area.
  • ‘Extension’ means adding to or increasing the floor area of an existing dwelling.

How to use this guide

To help you work out which permits you need, begin at Step 1 and answer the questions one at a time.

You may be asked to look at zones that affect the property, measure the property area, determine the height of the building and assess how much of the property will be garden area.

This guide only refers to alterations and extensions to the house itself for example changes to the floor, roof, walls or interior.

To perform works on an associated structure, such as a deck, shed, verandah, pool, pergola, fence or retaining wall, refer to Do I need a Permit? and consult the relevant guide.

Before you begin

If you plan to demolish any part of the dwelling in order complete your project, you may need a Planning or Building Permit for the demolition. 

Before finalising your design, check for easements on your property. Council prohibits the building of habitable structures over easements, as this prevents important maintenance work and blocks stormwater. If your design includes extending the house over an easement, you need to modify your plans. 

We recommend checking whether any restrictive covenants impact your property, as they may stipulate the material out of which you may construct your dwelling.


If you need help with Planning Permits, contact our Statutory Planning team on 9278 4888 or email Statutory Planning.   If you need help with Building Permits, contact our Building Services team on 9278 4999 or email Building Services.

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