Second Storey Planning: The Checks That Matter
Start with the existing home, then coordinate the design, engineering and approvals. Compare the complete project scope and agree how the work will affect your household before choosing a builder.
Existing home
Resolve assessment and design assumptions before committing to the layout.
Approvals
Confirm the pathway and conditions for your property.
Budget
Compare inclusions, allowances and costs outside the building quote.
During work
Agree access, household arrangements and the variation process.
Check the Existing Home Before Finalising Plans
A second storey changes more than the roofline. Before committing to a layout, ask your designer and structural engineer what needs investigating in the existing home. An attractive floor plan does not establish whether the proposed addition can be supported.
YourHome's renovation guidance recommends a qualified structural engineer for structural modifications. Arrange design and engineering together so assumptions are resolved before they become a construction problem.
| Planning decision | What to discuss | What to record |
|---|---|---|
| Existing structure | What site inspection, records and further investigations are needed? | The engineer's findings, assumptions and any work still to assess. |
| New layout | Where will stairs, rooms and services go, and what changes below? | A coordinated plan showing the work on both levels. |
| Design team | Who prepares plans and coordinates engineering and approvals? | Each consultant's scope, responsibilities and fees. |
| Reused plans | Can the design be adapted to this property, and do you have permission to use it? | Site-specific changes and the agreed rights to the drawings. |
Choose an architect or building designer whose experience and services fit the project. Check any required registration and ask what documentation is included. A job title or the age of the house alone does not establish suitability.
If the plans are still preliminary, ask builders to identify what they have assumed in their pricing. Keep the assessment findings, design revisions and quote documents together so everyone works from the same brief.
Compare the Whole Project Budget
Compare proposals against the same plans and specifications. Check allowances and exclusions before deciding which quote offers the best value. Consumer Affairs Victoria's quote guide explains why scope and references matter alongside price.
Use this checklist to find costs sitting outside the construction headline. Ask for an amount or a clear explanation of how each unresolved item will be priced.
| Budget item | What the proposal should clarify | A useful question |
|---|---|---|
| Design and assessment | Plans, engineering, investigations and revisions. | Which consultant services are included? |
| Approvals and inspections | Applications, certification and required inspections. | Who arranges them and pays the fees? |
| Existing-home work | Alterations below, service changes and repairs to affected finishes. | Does the scope cover both storeys? |
| Site and access | Scaffolding, temporary protection, removal and reinstatement. | What site assumptions could change the price? |
| Selections and allowances | Fixtures, finishes and items not fully specified. | What is allowed for, and what happens if the actual cost differs? |
| Living arrangements | Temporary accommodation, storage and other household costs. | What should I budget separately from the building contract? |
Set a contingency with advice from the project team about the unresolved risks at your property. Keep it separate from optional upgrades. Base the reserve on what still needs investigating, alongside a clear scope.
Ask for a schedule covering design, approvals, ordering, construction and completion. Confirm the assumptions behind the dates and how delays will be handled, rather than relying on a universal design or building duration.
Agree How the Work Will Affect Your Home
Ask prospective builders about recent additions involving similar existing homes. Speak with previous clients about communication, changes and the finished work. An arbitrary minimum project count is less useful than evidence relevant to your plans.
Plan for access and disruption
Before deciding to stay in the house, discuss the work stages with the builder:
- Which rooms, entrances and services will be unavailable?
- How will the existing home be protected from weather, dust and unauthorised access?
- Where will scaffolding, deliveries and waste go?
- What working hours and site conditions apply locally?
- Who will contact you if the programme changes or temporary accommodation becomes necessary?
Record the arrangement and a backup plan that suits your household. Do not assume the ground floor will remain usable throughout the job, or that temporary roof protection lasts a fixed number of weeks.
Treat changes as a written decision
Finalise important selections before work where possible. When a change is proposed, ask for its scope, cost adjustment, time effect and any design or approval implications. Follow the contract and local rules before authorising it.
The QBCC variation guide explains the written information needed for Queensland projects. Agree the price and schedule effect of the specific change.
Keep demolition and structural work with the right people
Do not treat roof removal or structural demolition as a DIY shortcut. Agree responsibilities with the builder and relevant professionals. Where asbestos may be present, national home guidance says to check before disturbing materials and use a licensed asbestos removalist for major renovations. Confirm investigation, removal and disposal scope separately; these services are not automatically included in every building quote.
Confirm Approvals, Contracts and Cover
Ask the council and the relevant certifier or building surveyor which approvals apply to your design and site. Record who obtains them, any conditions and what must be complete before each stage starts. Do not begin work that requires approval before that approval and its relevant conditions are in place.
Approval pathways vary
In NSW, complying development can combine planning and construction approval for eligible additions that meet its requirements. Other projects use a development application pathway. A second storey should not be assumed to qualify without assessment.
In Victoria, plans and permits guidance distinguishes a planning permit from a building permit. Where a planning permit is needed, it comes before the building permit. Requirements elsewhere should be checked with the local authority.
A neighbour's approval does not establish what is allowed on your property. Ask about applicable height, setback, heritage and other site constraints before committing to the design.
Put the scope and responsibilities in writing
Review the building contract with its plans and specifications. Check the price basis, allowances, exclusions, payment stages, programme, variation process, warranties and dispute steps. Resolve gaps before signing and seek independent legal advice on terms you do not understand.
The NSW contract guide is a useful state example. It also explains that a change needed to correct a contractor's own fault is not automatically an extra charge to the homeowner. Rules and contract requirements differ by jurisdiction.
Check the actual contractor and insurance
Check the contracting business's relevant licence or registration with your state regulator, including its status, scope and conditions. Ask for applicable insurance evidence and project-specific building cover where required. An ABN check does not establish trade qualifications or insurance.
Speak with your home insurer before the work and explain whether you will remain in the house. Ask how renovations, vacancy and the existing building are covered. Moneysmart's insurance guide explains the importance of reading inclusions and exclusions. Do not assume that all cover becomes void, or that the builder's policy covers everything.
A Short Checklist Before You Commit
- Keep one current set of plans, assessment findings and specifications.
- Resolve the approval pathway and responsibility for applications and inspections.
- Compare written scope, allowances and exclusions across proposals.
- Check the contracting business, relevant credentials and applicable insurance.
- Agree access, household arrangements, payment stages and how changes are handled.
For a broader project brief, see how to plan a second storey addition. Use this guide to prepare questions for your project team; it does not assess the structure or approval eligibility of an individual home.
Sources and Further Guidance
Official guidance checked on 14 October 2026. State examples illustrate differences; they do not establish approval eligibility, insurance cover or contract terms for your project.
