Planning a Home Extension in Melbourne: Step-by-Step Guide

Planning a home extension in Melbourne starts with a clear brief, a realistic budget and an understanding of the property. This guide explains the preparation steps before construction, so you can organise the decisions and information your project needs.

For help designing and building the project, visit our home extension service page. This article focuses on planning rather than providing a standard design, price or approval timeframe.

1. Define what the extension needs to achieve

Write down the rooms you need, the problems with the current layout and the features you want to retain. Separate essential requirements from optional features. Think about how your family will use the house over the coming years.

Collect a few examples of layouts or finishes you like, but treat them as a discussion tool. A design that works on another property may not suit your block, structure or budget.

2. Gather information about the existing property

Locate existing plans and any relevant approval documents you hold. Note the property address, access arrangements, visible building issues and the location of services where known.

The design team may need a site survey, investigation of the existing building, engineering advice and other reports. Roof connections, floor levels, drainage and structural support should be considered before the design is finalised.

3. Compare the extension options

A rear or side addition may improve the connection to outdoor living. An upstairs addition may retain more garden space, but introduces stairs and structural requirements. Assess the whole layout, including changes needed within the existing house.

Explore single storey extensions and double and second storey extensions for the specialist service options. For a period property, consider the original character alongside the new accommodation.

4. Establish a budget and scope

Set an approximate budget early and explain whether it includes design, approvals, construction, existing-room renovations and temporary accommodation. Discuss the priorities if the preferred design exceeds the available budget.

A floor-area estimate alone is not a detailed quotation. Access, structural changes, services, finishes and the condition of the existing building all influence the scope. Read our Melbourne extension cost guide for the main pricing considerations.

5. Check planning and building approvals

Check with the local council whether the proposal needs a planning permit. Where it does, planning approval must be obtained before a building permit can be issued. A registered building surveyor assesses the building permit application.

Confirm the approvals needed for your property and who will obtain them. Your agreement should identify the responsibilities. Consumer Affairs Victoria explains the roles in its building plans and permits guidance.

6. Develop the drawings and specifications

Work through the room layout, structural design, materials and key selections. Document what is included in the addition and what changes are required in the existing rooms.

Record decisions about windows, doors, kitchens, bathrooms and finishes. Clear drawings and specifications help the builder prepare a quotation and reduce uncertainty when comparing scopes.

7. Review the quotation and contract

Compare the work described, allowances, exclusions and responsibilities. Ask how unresolved selections or site conditions are treated and how changes will be documented.

Check the proposed stages, payment arrangements and likely disruption. Make sure the scope you agree to is reflected in the documents, rather than relying on conversations alone.

8. Plan for construction and daily life

Discuss access, deliveries, protection of the existing home and whether essential rooms and services will remain usable. Temporary accommodation may be needed, depending on the work and safe living arrangements.

Agree how progress and decisions will be communicated. Timing depends on design development, approvals, site conditions and construction scope, so avoid assuming a standard start or completion date.

Your extension planning checklist

• A clear list of essential rooms and layout improvements
• An approximate budget and agreed scope priorities
• Available property plans and site information
• Advice on the approvals and investigations needed
• Developed drawings and specifications
• A quotation and contract describing the work
• A plan for access, disruption and communication

See Cameron Construction’s design and construction process for our stages, or discuss your extension plans with our team.