If you’ve been living in Sydney’s inner suburbs for a while, you probably know the feeling — the kids are getting bigger, space is getting tighter, and suddenly your once-perfect home feels a bit small. You love your street, the neighbours, and the cafes around the corner, but moving just isn’t appealing with Sydney’s property prices.
That’s when most families start asking the same question: What if we just build up?
A second-storey addition is one of the smartest ways to create more room without losing your backyard or leaving the suburb you love. It can turn an older cottage into a family home with space to grow, but naturally, everyone wants to know what it will cost. Let’s walk through that, based on what we see every week on real Sydney builds.
1. Why so many homeowners build up instead of moving
In suburbs like Balmain, Leichhardt, Marrickville, and Drummoyne, land is at a premium. Finding a bigger home nearby often means spending hundreds of thousands more — not to mention stamp duty and agent fees.
That’s why adding a second level makes sense. It’s not only about space. You can:
- Keep the original charm of your home.
- Gain more light and airflow by lifting bedrooms upstairs.
- Open up the ground floor for larger living and dining areas.
- Add serious value if you ever decide to sell later on.
At Ardent Construction, we see families choosing this path every year because it simply makes financial and practical sense.
2. So, how much does a second-storey addition actually cost?
Let’s be honest, the range is wide because every home is unique. But as a general rule, most additions across Sydney’s inner suburbs sit between $350,000 and $650,000.
The variation depends on what you’re adding and how your existing home is built. A basic level with a couple of bedrooms might fall toward the lower end. A larger extension with a bathroom, master suite, and premium finishes could easily push past $600,000.
Here’s a simple comparison to give you an idea:
| Project type | Typical cost range | What’s included |
|---|---|---|
| Basic addition | $300,000–$400,000 | One or two rooms, standard finishes |
| Mid-range | $400,000–$550,000 | Bedrooms, ensuite, new staircase |
| Premium build | $550,000–$700,000+ | Custom layout, complex roofline, higher-end materials |
These prices include the structure, roof, stairs, plastering, and basic finishes, but not always kitchens or bathrooms those are usually costed separately.
3. The biggest factors that affect cost
No two projects are ever the same, but the main drivers behind your final price usually come down to a few practical things.
Existing structure:
If your current house wasn’t designed to hold another level, your builder may need to reinforce the foundation or walls. That extra engineering can add anywhere from ten to fifty thousand dollars depending on what’s required.
Roof removal:
Almost all second-storey builds mean taking off part or all of your roof. If the roofline is complex or heritage-listed, there’s more labour involved.
Access:
Sydney’s inner streets can be tricky. Narrow lanes, limited parking, and overhead wires sometimes mean cranes or extra scaffolding are needed, which adds time and cost.
Design and materials:
A simple gable roof and straightforward layout will always cost less than a detailed architectural design with custom windows or steel framing.
Finishes:
This is where people’s tastes differ most. Choosing timber floors, high-end windows, or marble tiles can quickly bump up the budget — but they also add long-term value.
4. A look at average prices around Sydney
When we look across different projects we’ve completed in the inner suburbs, the numbers usually land in this range:
| Type of addition | Average total cost | Typical size | Example layout |
|---|---|---|---|
| Small extension | $350,000 | ~40m² | Bedroom + ensuite |
| Standard | $450,000 | ~60m² | Two bedrooms + bathroom |
| Larger / custom | $600,000+ | 80m²+ | Master suite, balcony, home office |
Those are averages, but they hold pretty steady across areas like Haberfield, Annandale, and North Sydney. The main thing that shifts the cost is the existing condition of the home and the level of finish you want.
5. Don’t forget the behind-the-scenes costs
This is where many homeowners get caught out. The build cost is only part of the picture. You’ll also need to allow for:
- Design and drafting: about $8,000–$20,000, depending on detail.
- Council and certification fees: anywhere from $2,000–$10,000.
- Temporary accommodation: if your roof is off, you may need to move out for a few months.
- Electrical and plumbing upgrades: older homes sometimes need new wiring or pipes.
- Asbestos removal: common in houses built before 1990.
At Ardent Construction, we talk through all these extras early so nothing catches you by surprise later.
6. What you actually gain from going up
Beyond extra bedrooms, a second-storey addition changes how your home feels.
You can free up the ground floor for open-plan living or turn a dark hallway into a bright living area. Upstairs might become a private retreat, a home office with a view, or even a playroom for the kids.
One client in Drummoyne turned a dated two-bedroom home into a four-bedroom haven by adding 65 square metres upstairs — including a small balcony overlooking the bay. They didn’t just gain space; they gained lifestyle.
You can see more examples like that on our Home Extensions Sydney page.
7. How most people finance their addition
Second-storey projects are a big investment, so it’s important to plan the money side properly.
Many homeowners tap into home equity or refinance their mortgage. Some combine savings with a small loan to avoid over-borrowing. If you want a deeper look at financing, check out our article on Smart Ways to Finance Your Home Renovation in Sydney.
The main thing is to talk to your bank early so that funds are ready before the build starts. Builders like us can also set up progress payments that match the construction stages, keeping everything simple and transparent.
8. Typical timeline
Adding a level to your home takes time — but with proper planning, it runs smoothly.
A typical build in the inner suburbs might look like this:
- Design and planning: 1–2 months
- Council approval: around 2–3 months
- Construction: roughly 5–6 months
- Final touches and inspection: 1–2 weeks
Weather and approvals can cause small delays, but an experienced team will manage that and keep communication open from start to finish. You can read more about our approach on the Residential Construction page.
9. How much value does it add?
Done well, a second-storey addition can lift your home’s value by 20–40%. Real estate agents across Sydney’s inner west often see these homes selling well above comparable single-level houses.
Buyers love the mix of character and space, especially families who want to stay close to the city. In one recent project we completed in Five Dock, the owners spent just under half a million and saw their property valuation jump by nearly $500,000 within a year.
10. Ways to manage or reduce cost
There are always ways to make smart decisions without compromising quality.
- Stage the build: finish the structure first, complete interiors later if needed.
- Simplify the design: a straightforward roofline saves a lot in materials and labour.
- Reuse existing materials: sometimes bricks, tiles, or flooring can be repurposed.
- Choose quality over quantity: invest in what adds long-term value, insulation, layout, and structural quality, instead of cosmetic extras.
At Ardent Construction, we focus on practical design that delivers value for every dollar spent.
11. Real story from the Inner West
A family in Petersham came to us after debating whether to move or extend. Their two-bedroom federation home was perfect in every way except size.
We added a 70-square-metre second storey with two bedrooms, a bathroom, and a retreat space. They stayed in temporary accommodation for a few months, and within eight months they had their dream home back, only bigger, lighter, and far more functional.
The total cost came to around $460,000, and today their property value sits comfortably above $2.4 million.
12. Common questions we’re asked
Do I need council approval?
Yes, all second-storey builds require approval. We handle that paperwork for you.
Can I live in the house during construction?
It depends on the work. If the roof is completely removed, most people move out temporarily for safety and comfort.
Are second-storey additions possible on older homes?
Absolutely, though they sometimes need structural strengthening first.
How do I get started?
Reach out through our Contact page, and we can visit your home, discuss ideas, and provide an estimate tailored to your site and design.
A second-storey addition isn’t just about adding rooms; it’s about reshaping your lifestyle without leaving the place you call home. Sydney’s inner suburbs are full of character, and building up lets you keep that charm while gaining the space your family needs.
At Ardent Construction, we specialise in complex extensions, heritage projects, and complete renovations. We take the time to understand your home, your budget, and your goals — so the finished result feels natural, not tacked on.