House Extension Planning: Key Steps for Brisbane and Redlands

Essential Considerations Before Planning Your House Extension

The groundwork you lay before any design work begins is crucial to the success of your extension. When executed correctly, the new spaces seamlessly integrate with your existing home. Failing to address these details can lead to awkward design compromises, such as mismatched roof lines or structural setbacks. This is why we thoroughly assess what is applicable to your property before commencing the design phase.

Start by clarifying the following key aspects.

• Identify your required spaces: Do you need a master bedroom suite, an additional living area, extra bedrooms, or space for a parent moving in? Be specific about the intended use of each room.
• Assess the structural integrity of your home: Since an extension connects to your existing structure, it’s vital to ensure that the foundation is sound and capable of supporting the new addition.
• Evaluate your block’s available space: Most extensions are added to the back or side of the house. The space you have will determine your design possibilities.
• Decide if you want to remain in your current location: Consider whether the neighbourhood holds more value for you than relocating to a different area.

If the existing house presents challenges, our guide on whether to knock down and rebuild or renovate can assist with that decision. Our dedicated page on house extensions in Brisbane outlines what we can construct for you.

Is Approval Required for a House Extension in Queensland?

Absolutely. You must obtain building approval prior to commencing any extension work (Brisbane City Council: extension approvals).

This approval is granted by a private building certifier rather than the council itself. In Brisbane, the council acts as a referral agency, providing advice on your application as necessary (same page). The process is similar in Redlands: the certifier approves the work and submits the endorsed documents to the council (Redland City Council: private building certifiers).

When Is Council Planning Approval Necessary for a House Extension?

Building approval is your first step. some properties may also require planning approval, which depends on the overlays that apply to your block.

Understanding Character and Heritage Overlays in Brisbane

Brisbane’s inner suburbs feature many character homes. If your property falls under the Traditional Building Character overlay, Brisbane City Council states that “planning approval for external extensions is generally required” (Brisbane City Council: extension approvals).

For homes within the Pre-1911 building overlay, additional regulations apply: “Extensions should not alter the original parts of the house” (Brisbane City Council: heritage properties). This directive influences both the location and design of your extension.

Navigating Flood Overlays and House Extensions in Brisbane

Flood risks are a significant consideration for any extension located near a creek, river, or in low-lying areas. A FloodWise property report from Brisbane City Council will indicate if “City Plan overlays for river, creek, overland flow, and coastal hazard floods affect” your property (Brisbane City Council: FloodWise property report). This report also details requirements for habitable floor levels, making it essential to obtain prior to design work.

House Extension Regulations in the Redlands

In the Redlands, the overlays impacting your site are also crucial. According to Redland City Council’s guidelines for residential structures, planning approval is typically necessary when your site is marked by an overlay, which elevates the assessment level for a dwelling house. The relevant overlays include heritage, flood, storm tide hazard, and coastal protection (Redland City Council: residential structures). In coastal suburbs like Cleveland, Raby Bay, and Wellington Point, it’s advisable to investigate coastal and storm tide overlays early in the planning process. If your extension does require a development application, our guide on the timeline for a Redland DA addresses this issue.

What Is the Minimum Distance a House Extension Can Be from the Boundary?

The distance depends on your lot size, zoning, and local council regulations. There is no universal measurement that applies to every property.

Queensland's siting rules are currently undergoing changes. The prior Queensland Development Code sections on house siting, MP 1.1 and MP 1.2, are transitioning to the Queensland Housing Code, with a transition period that spans from 1 September 2026 to 1 September 2029. The old regulations remain in effect until your council implements the new code (Business Queensland: Queensland Development Code). Your certifier will clarify which regulations are applicable to your property.

Councils also have the authority to establish their own siting rules. For instance, Redland City Plan “provides alternative siting provisions” in certain low-density residential zones, addressing building height in relation to “obstruction and overshadowing” (Redland City Council: design and siting).

Engaging in discussions with neighbours can be beneficial, even if not legally required. Redland notes that while “no legislative requirement exists to consult with your affected neighbour” (same page), informing them about changes that may affect their views or sunlight can foster goodwill.

How to Locate Your Existing House Plans Before an Extension

Designing an extension relies heavily on the existing layout of your home, so accessing the original plans is helpful. In Brisbane, you can request approved building plans from the council for homes “built, altered, or renovated after 1987,” although a fee is applicable for each copy (Brisbane City Council: request building plans).

In the Redlands, a residential property search may include approved domestic building plans (Redland City Council: residential property search form).

If no plans exist in the council’s records, this is often the case for homes built before the council’s archival system was established.

Choosing Between a Single or Two Storey Extension: Layout Considerations

Both single and two-storey extensions are viable options. The decision typically hinges on your property layout and the specific rooms you require.

• Single storey extension: commonly constructed at the back, these extensions enhance living areas and keep new bedrooms on the same level as the existing house.
• Two storey extension: these can extend from the back or side, offering living space on the ground floor and bedrooms above. This option maximises room while minimising yard usage.

Regardless of which option you choose, your extension should be designed to complement the existing home. Elements such as roof lines, ceiling heights, floor levels, windows, and materials must align seamlessly. Sloped and narrow blocks require additional planning, which our resources on sloping block builds and narrow block builds will address.

Can You Remain in Your Home During Extension Work?

Typically, yes. The critical aspect to plan meticulously is the junction where the new structure connects to the existing house. We collaborate with you during the design phase to outline the construction process and what to anticipate before work commences.

Avoiding Common Pitfalls in House Extension Planning

Here are some common mistakes to steer clear of.

• Designing without first checking local regulations: discovering an overlay or siting rule after plans are drafted may necessitate a complete redesign.
• Viewing the extension as merely a box added to the back: mismatched roof lines, floor levels, and ceiling heights can make the extension feel like an afterthought, which also affects the interior experience.
• Delaying approvals until the end: since approvals influence design, they should be part of the initial planning phase.
• Neglecting to verify your builder’s qualifications: all licensed contractors in Queensland are listed on the QBCC licensee register (QBCC: find a licensed contractor). Most residential building projects also need to be covered by the Queensland Home Warranty Scheme (QBCC: what work requires insurance), protecting homeowners if a contractor “fails to complete contracted works or rectify defects” (QBCC: the Queensland Home Warranty Scheme).

How a Design and Construct Builder Approaches Your Extension Project

Engaging a design and construct builder simplifies the process, as the planning, design, approvals, and construction are managed by one cohesive team. Here’s how we structure the planning of your extension:

• Site assessment: analysing the existing structure, floor levels, setbacks, services, and how the extension will integrate with your home.
• Concept design: determining the placement of new rooms, how you will transition between the old and new spaces, and the overall appearance from both the street and yard.
• Approvals: we identify the necessary approvals for your property, including any applicable overlays, and manage the entire approval process.
• Design and specification: we finalise finishes, joinery, and fixtures before construction begins, ensuring that the new addition harmonises with the rest of your home.

Frequently Asked Questions About House Extension Planning

Who is responsible for approving house extensions in Brisbane?

A private building certifier is responsible for granting building approval. If your property is subject to an overlay, such as the Traditional Building Character overlay, you will likely need to obtain planning approval as well.

Who manages the approvals for my house extension?

We take care of the entire approvals process. We determine what your property requires, including any relevant overlays, and handle the approvals as part of your project.

Can a garage be incorporated into an extension?

Yes. Converting a garage can transform unused space into functional living areas, such as a guest suite or an additional living room, provided that proper floor levels, insulation, windows, and ventilation are included.

Do you undertake house extensions in the Redlands?

Yes, we specialise in extensions throughout the Redlands, including Cleveland, Raby Bay, Ormiston, Wellington Point, Thornlands, Birkdale, and Capalaba, along with Brisbane’s inner eastern suburbs.

What is the first step in planning my house extension?

Schedule a consultation with us. We will assess your home and block, discuss your desired rooms, and clarify what is feasible for your site.

Consult Iconic Homes and Construction for Your House Extension Plans

Schedule a consultation, and we will evaluate your home and block with you. Alternatively, learn more about our house extension services in Brisbane and the Redlands.

Iconic Homes and Construction is a design and construct builder located in Cleveland, providing services across Brisbane, the Redlands, and Bayside. QBCC licence 15141694. Proud member of Master Builders Queensland.