Home Extension Canberra

Moving to a bigger home in Canberra is expensive. Stamp duty on a $1.5 million purchase runs to around $60,000. Add agent fees, removalists, and the disruption of uprooting the family, and the numbers rarely stack up the way people expect. A well-designed extension can give you the space you need for a fraction of what moving costs, and you keep the suburb, the school zone and the community you’ve built.

Rentoule Projects builds home extensions across Canberra’s inner suburbs. Jeff Rentoule holds an ACT builder’s licence (ACT 20211145) and manages every project personally from design through to handover. We price extensions on a fixed-price basis so you know the full cost before work starts.

Types of Home Extensions We Build

Ground Floor Rear Extensions

The most common extension type in Canberra. We extend the living area, kitchen or master bedroom out to the rear of the block. This works well on most standard Canberra blocks and can significantly improve the flow and light in your home.

Side Additions

Where rear access is limited or the block is wide, a side addition can add a bedroom, home office or bathroom without touching the rear yard. Side setback requirements apply, so we check planning rules early in the process.

Alfresco and Outdoor Living Areas

An outdoor living area extends your usable space without increasing the building footprint substantially. We build covered alfresco areas, decks, pergolas and outdoor kitchens that connect to the internal living area and work with Canberra’s climate.

Open-Plan Reconfiguration

Sometimes an extension works best when combined with a reconfiguration of the existing floor plan. We remove walls, install steel beams and redesign internal layout as part of the broader extension project.

Garage Conversions

An existing double garage can become a self-contained studio, home office, teenager’s retreat or gym. This is one of the more cost-effective ways to add usable space when the footprint already exists.

Granny Flats and Secondary Dwellings

A secondary dwelling on your block can house family or generate rental income. ACT planning rules allow secondary dwellings on blocks above a certain size. We advise on eligibility and manage the approvals process.

Extension vs Moving: The Real Cost Comparison

People often assume moving is simpler than extending. The costs tell a different story.

If you’re upgrading from a $1.2 million home to a $1.7 million home in Canberra, stamp duty alone is around $60,000 to $70,000. Add agent fees, removalists and temporary accommodation and you’re looking at $90,000 to $120,000 in transaction costs before you’ve changed anything about your living situation.

A ground floor extension of 30 to 40 square metres can be delivered for $120,000 to $200,000. You end up with a better home in your existing suburb, no stamp duty, no agent, no school change.

The comparison is different for everyone. But it’s worth running the numbers before you go to market.

Extension Costs in Canberra

Home extension costs in Canberra currently run from around $3,000 to $7,000 per square metre, depending on scope, finishes and site conditions. A straightforward single-room extension at the lower end of finishes sits around $3,000 to $4,000 per square metre. A full-quality extension with structural work, high-spec joinery and large glazing runs toward $5,000 to $7,000 per square metre.

Factors that affect cost include:

Whether structural work is required, including wall removal and steel installation
The level of glazing and sliding door systems
Kitchen or bathroom inclusions within the extension
Roof connection details and the complexity of tying into the existing structure
Site access and soil conditions
Finishes selections across flooring, joinery and fittings

Jeff will walk you through realistic cost expectations during the initial consultation. We don’t underquote.

The Extension Process

Initial consultation. Jeff visits your home to understand what you want, inspect the site and talk through what’s achievable. No charge for this visit.
Design and scope. We work through the design either with your own architect or designer, or we co-ordinate this for you. The scope is developed in detail so the quote covers everything.
Development application (if required). We advise on whether your extension needs a DA or qualifies as exempt development. Where a DA is required, we manage the submission to the ACT Planning Authority.
Fixed-price contract. Once design and approvals are in place, we issue a fixed-price contract covering the full scope of works. Every cost is itemised. No surprises.
Construction. Jeff manages the build on site. You get regular updates and clear communication throughout.
Handover. We carry out a final inspection before handing over. All works are completed to standard before we call the job done.

ACT Planning Rules for Extensions

Whether your extension needs a development application depends on the specifics of your project and your block. The ACT Planning Authority sets the rules.

Exempt development. Some extensions qualify as exempt development under the Territory Plan. These do not require a DA. Conditions include limits on overall block coverage, rear setbacks, wall height and proximity to boundaries. An outbuilding or small rear addition may fall into this category.

Code-track approvals. Many standard residential extensions are assessed as code-track development applications, which have a faster approval timeframe than merit-track applications. These are assessed against specific criteria in the Territory Plan.

Key rules to be aware of:

Block coverage limits restrict how much of your block the buildings can cover in total
Rear and side setbacks specify minimum distances from boundaries
Wall height limits apply to single-storey additions
Boundary clearances affect where an extension can be sited on the block

For full details, see the ACT Planning Authority website. Jeff will advise on what applies to your specific block and proposed extension during the consultation.

Suburbs We Work In

We work across Canberra’s inner suburbs. These are the areas where extending makes the strongest financial sense, because the land value is high and moving costs are steep.

North Canberra

Braddon and Turner. Smaller blocks and proximity to the city make extension a popular choice over moving. Rear extensions and garage conversions suit these suburbs well.

Ainslie and Campbell. Larger blocks with established homes. Rear extensions and alfresco additions are popular here.

Dickson and O’Connor. Good block sizes and strong school zones. Extending is often a better financial decision than selling and buying up.

South Canberra

Griffith and Narrabundah. Post-war homes on standard blocks. Ground floor rear extensions and open-plan reconfigurations work well here.

Forrest and Yarralumla. Larger blocks with prestige homes. Extension work here is often high-spec and we work to that standard.

Deakin and Red Hill. Established suburbs where residents prefer to stay put. Extension demand is strong in both areas.

Frequently Asked Questions

Do I need DA approval for an extension?

It depends on the size and type of extension, and your block’s specific planning conditions. Some smaller extensions qualify as exempt development and do not need a DA. Most extensions of meaningful size will need either a code-track DA or a building approval. We review your site and proposed scope early in the process and advise exactly what’s needed before you commit to anything.

How long does a home extension take?

A straightforward ground floor extension typically takes eight to fourteen weeks once construction starts. Larger extensions take longer. If a DA is required, that adds six to twelve weeks before construction. We give you a realistic timeline during the planning phase.

Can I stay home during the build?

For most ground floor extensions, yes. The building works are typically at the rear of the home and the existing living areas remain accessible. During certain stages, particularly when structural tie-ins are made or utilities are affected, there may be short periods of disruption. Jeff will walk you through what to expect at each stage before work starts.

What is the difference between a ground floor extension and a second storey?

A ground floor extension expands your home’s footprint outward across the block. A second storey addition builds upward on the existing footprint. Ground floor extensions are generally simpler, faster and less disruptive. Second storey additions require a full structural assessment of the existing home, almost always need DA approval, and involve more complex construction. Both are viable depending on your block size and what you’re trying to achieve. We can advise on which suits your situation.

How much value does an extension add to my home?

A well-designed extension typically adds more value than it costs to build in Canberra’s inner suburbs. The exact uplift depends on the suburb, the quality of work and what the extension adds functionally. We can’t guarantee a specific figure, but in our experience, inner suburb extensions are a sound investment.

Ready to Talk?

If you’re thinking about extending your Canberra home, the first step is a free consultation. Jeff visits your property, listens to what you want to achieve and gives you an honest view of what’s possible, what it will cost and how long it will take.

Rentoule Projects is an HIA member and Master Builders ACT member. We hold ACT builder’s licence ACT 20211145 and NSW builder’s licence 453726C. We carry a 5.0 star rating from 19 Google reviews.