When space is tight but the need for extra room is growing, a double storey extension offers a smart, future-focused solution. For many Melbourne homeowners, building upward instead of outward can transform an existing home into a spacious, functional and beautifully modern residence, without sacrificing precious garden or outdoor space.

At Karja Builders, we understand that choosing to add a second storey is a major commitment. With over 15 years of experience in the building industry, we help clients weigh the options, understand the structural and planning considerations, and navigate the complexities of the design and construction process with confidence. If you’re unsure whether a second-storey addition is right for your home extension project, this guide will take you through everything you need to know.

Why Consider a Second Storey Extension?

A second storey extension is ideal when you want to add more space but have a limited footprint or narrow site. Rather than compromising your outdoor area or entertaining space with a ground-floor extension or side extension, building vertically gives you the best of both worlds: additional living space and preserved land.

Some common motivations to build a second storey include:

• Accommodating a growing family with extra bedrooms and a bathroom upstairs
• Creating a home office or private retreat away from the main living area
• Improving the appearance of your home with a modern architectural upgrade
• Increasing the value of your property without needing to relocate
• Taking advantage of views, orientation, and natural light by elevating living zones

If you want to learn how this compares to a single-storey extension, explore our article here:
Single vs Two Storey Extension – Which is Right for You?

Planning Your Double Storey Extension

Adding a second storey to your home requires careful planning to ensure it blends seamlessly with the existing home. Key elements to consider include:

Structural Feasibility

Before you start designing your second-storey extension, a structural engineer or architect must assess whether your home can support an extra level. The strength of the original foundation and wall structure will determine what’s possible, and whether reinforcement is needed.

Design Cohesion

The design of the extension should match your existing home’s character or reimagine it entirely with a cohesive architectural style. Consider how the roofline, cladding, windows, and proportions will work together. A well-executed storey extension can drastically improve the appearance of your home.

Layout and Functionality

A double storey extension gives you flexibility in how you use your home. Many homeowners choose to relocate bedrooms upstairs to free up the ground floor for open-plan living. Others add a parent’s retreat, rumpus room, or second lounge to give the family space to spread out.

Permits, Planning and Regulations

As with all extensions in Melbourne, adding a second storey requires specific approvals. You’ll likely need both a planning permit and a building permit, depending on your location, property type, and the design of the extension.

Check the full requirements here:
Victorian Building Authority – Permits

Working with an experienced renovation builder helps streamline this process. You’ll also need to ensure compliance with local council guidelines, building regulations, and consider how your storey house extension will affect neighbours in terms of overshadowing, privacy, and setbacks.

Costs Involved in Building a Second Storey

The cost of a second-storey home extension depends on various factors, including:

• The size of the extension
• Site access and structural modifications
• Quality of materials and finishes
• Whether wet areas (like a bathroom) are added upstairs
• Design complexity and architectural input

On average, a second storey addition in Melbourne may cost between $2,500 and $4,000 per square metre. However, depending on the scope, complexity, and level of finish, total costs can exceed this range, particularly for architecturally designed extensions or sites requiring structural reinforcement.

Keep in mind the overall cost will also include planning fees, necessary permits, demolition, and possibly temporary relocation costs if access to the ground floor is limited during construction.

Pros and Cons of a Double Storey Extension

Pros:

• Adds significant space without reducing outdoor living
• Increases the value of your home
• Allows for more privacy between living and sleeping zones
• Ideal for narrow blocks or existing homes with limited yard

Cons:

• Generally more expensive than a single-storey extension
• Longer building process and more disruptive during construction
• May require you to move out temporarily
• Can be complex in heritage overlays or tight zoning conditions

Maximising Your Investment

A well-executed second storey extension can deliver excellent long-term return on your investment, especially in tightly held Melbourne suburbs where land is limited. It’s important to work out your budget early, stay realistic about timelines, and prioritise quality design.

A smart layout, generous natural light, and thoughtful detailing are key to ensuring your new upstairs extension enhances how you use your home every day, not just how it looks.

For more general guidance and inspiration, explore our overview of home extension options here:
Home Extensions – Karja Builders Melbourne

Is a Second Storey Extension Right for You?

If you’re looking to extend your home to suit a growing family, preserve your backyard, and unlock greater functionality, a double storey extension could be the ideal choice. While it involves a more complex extension and renovation process than building out, the long-term benefits, more room, greater privacy, and increased property value, can make it well worth the investment.

Get in Touch to Discuss Your House Extension Options

Whether you’re just beginning to explore extension ideas or ready to begin designing your second storey extension today, Karja Builders is here to support you every step of the way. Our expert team can help you evaluate your site, understand your options, and deliver a home that evolves with your lifestyle.