If you love where you live but have outgrown your home, a second storey addition can be the perfect solution. It gives you the space you need without sacrificing your backyard or leaving the neighbourhood you’ve invested in.

In Sydney, where land is limited and families want to stay close to schools, beaches, and community hubs, building up is one of the smartest ways to add long-term value and transform your lifestyle.

At Phase Projects, we specialise in complex and architectural second-storey additions, the kind that blend seamlessly with your existing home while elevating both design and liveability.

How Much Does It Cost to Add a Second Storey in Sydney?

The cost of adding a second storey in Sydney typically starts from $450,000 to $800,000+, depending on the size, design complexity, and level of finish.

Luxury additions with custom joinery, premium materials, and detailed architectural features can exceed $900,000, especially if structural upgrades are required.

Here’s what usually impacts your overall cost:

• Foundation strength: whether the existing structure can support another level.
• Roof removal and rebuild: most additions require the existing roof to be removed and replaced.
• Access and site constraints: narrow Sydney streets or tight blocks may add complexity.
• Finishes and inclusions: flooring, staircases, windows, and ensuite fit-outs.
• Approvals and design documentation: DA or CDC applications, engineering, and energy reports.

At Phase Projects, we start every project with a detailed structural and cost analysis, so you have clarity before committing.

Is It Cheaper to Add On or Add a Second Storey?

In many Sydney suburbs, adding a second storey can be more cost-effective, and certainly more practical than extending on the ground level.

Here’s why:

• Land is expensive: ground-floor extensions often mean sacrificing valuable outdoor space.
• Less disruption: upper-floor additions can often be built with limited impact to your daily routine.
• Higher returns: second-storey homes have stronger resale value, especially in view or coastal locations.
• Zoning benefits: in areas with small blocks, councils often encourage vertical expansion over horizontal.

Ground-floor extensions are still a great choice if you have ample land or need accessibility on one level, but in Sydney’s tighter suburbs, building up almost always delivers better value per square metre.

What Is the Average Cost of a 2-Storey Extension?

For full two-storey extensions, such as when the ground floor is renovated along with the new upper level, prices typically start around $700,000 to $1 million+.

This approach is ideal when:

• You want to reconfigure your ground floor for open-plan living.
• You’re modernising the entire façade.
• You’re adding luxury features such as new bathrooms, balconies, or custom staircases.

A two-storey extension is often more transformative than a second-storey addition alone, turning an older Sydney home into something truly contemporary.

At Phase Projects, we specialise in these complex upgrades, from heritage Federation and Californian bungalows to modern rebuilds in suburbs like Coogee, Bexley, and Blakehurst.

Can You Add an Upstairs to an Already Existing House?

Yes, in most cases, you can add a second storey to an existing home, but only after a structural assessment confirms your foundation and framing can support the additional load.

Older Sydney homes, particularly those built before the 1980s, may require foundation strengthening or steel framing to safely accommodate another level.

Our process includes:

1. Site inspection and engineering assessment: to determine structural capacity.
2. Concept design and feasibility: ensuring compliance with council controls and height limits.
3. Full design documentation: integrating stairs, services, and finishes into your existing layout.
4. Approvals and construction: managing all DA or CDC submissions, engineering, and build phases.

In some heritage or terrace-style homes, a loft or attic conversion may be a better option, delivering new living space with less structural intervention.
Read our related article on Attic Conversions Sydney.

Why Sydney Homeowners Are Building Up

Second-storey additions are about more than gaining space — they’re about unlocking lifestyle potential.

With a well-designed upper level, you can:

• Move bedrooms and bathrooms upstairs to create open living areas below.
• Capture city, coastal, or district views.
• Create dedicated home offices or parent retreats.
• Future-proof your home for growing families or multi-generational living.

At Phase Projects, every second-storey addition is designed to feel original, not an afterthought. From exterior finishes to interior detailing, we make sure the new space blends seamlessly with your existing home.

The Phase Projects Difference

We’re not a volume builder. We take on a select number of architectural renovations and extensions across Sydney each year, ensuring every project receives the focus, design thinking, and craftsmanship it deserves.

Our director, Mohamed Tawil, works directly with clients from concept to completion, supported by a trusted team of engineers, designers, and tradespeople who specialise in complex builds.

From structural integrity to seamless finishes, our goal is simple: to deliver a second storey that enhances the way you live, and increases the value of your home for years to come.

Ready to Move Up?

Whether you’re exploring options or ready to start designing, our team will guide you through the process, from structural feasibility to final handover.

Contact Phase Projects today to book a consultation and learn what’s possible for your home.