A second storey addition doubles your living space without reducing backyard area. It costs $250,000 to $600,000+ in Sydney and takes 16 to 30 weeks to build. For families on standard 500 to 700m² Sutherland Shire blocks, going up is often the only practical option for more space.
At Dura Group, we’ve been building second storey additions across the Shire for over 25 years. This guide covers everything you need to know before going up.
Why Go Up Instead of Out?
- Keep your backyard: On a standard 500 to 700m2 Shire block, going out means losing outdoor space. Going up keeps it all
- Views: Many Sutherland Shire properties gain bush views, district views, or even water glimpses from a second level
- Better layout: Separating living areas (downstairs) from bedrooms (upstairs) creates a floor plan that works well for families
- Block limitations: If your home is already close to side and rear setback limits, going up may be the only option for more space
Second Storey Addition Costs
In Sydney, second storey additions cost $4,500 to $7,000 per square metre fully fitted out. See our full home extension cost guide for detailed breakdowns.
- Partial second storey (30 to 50m2): $250,000 to $350,000. Adds 2 to 3 bedrooms and a bathroom
- Full second storey (60 to 100m2): $350,000 to $600,000+. Complete upper level with bedrooms, bathroom, living area, and balcony
The higher cost compared to ground floor extensions reflects the structural work required: reinforcing the ground floor, removing and rebuilding the roof, scaffolding, and working at height. Our Sydney building costs guide breaks down current per-square-metre rates.
What’s Involved in a Second Storey Addition
Structural Assessment
Before anything else, a structural engineer assesses whether your existing ground floor can support a second storey. This means checking:
- Foundation type and condition (strip footings, slab, piers)
- Wall framing capacity (timber stud, brick, double brick)
- Roof structure and removal requirements
- Load paths and where new support may be needed
Most Sutherland Shire homes built in the 1970s and 80s have brick veneer walls on strip footings. These can often support a second storey with targeted reinforcement rather than complete foundation replacement.
Council Approvals
Second storey additions always need council approval, either through a Sydney DA approval service. Key council considerations include:
- Height limits: Most residential zones in the Shire have an 8.5m to 9m height limit
- Overshadowing: Council assesses the shadow your addition casts on neighbouring properties
- Privacy: Upper floor windows and balconies facing neighbours may need screening or offset
- Floor space ratio: The total floor area must stay within the FSR limit for your block
We handle the entire approval process, including architectural plans, engineering, shadow diagrams, privacy assessments, and BASIX certificates. Our design and build approach means one team manages it all.
Construction Process
A second storey addition is a 16 to 30 week build:
- Weeks 1 to 3: Site setup, scaffolding, temporary weather protection
- Weeks 4 to 6: Roof removal and structural reinforcement of ground floor
- Weeks 7 to 10: Upper floor framing, new roof structure
- Weeks 11 to 14: Roofing, windows, external cladding
- Weeks 15 to 20: Internal fit-out (plasterboard, plumbing, electrical)
- Weeks 21 to 26: Bathroom, flooring, painting, staircase
- Weeks 27 to 30: Final fixtures, external works, and handover
The Staircase
Adding a staircase takes space from the ground floor. Typically 3 to 4m2 of floor area on both levels. We plan staircase location carefully to minimise disruption to the existing layout. Common positions include replacing a hallway cupboard, using part of a living room, or building into the new extension footprint.
Living at Home During Construction
Most families stay in their home during a second storey build. The ground floor remains liveable while the upper level is constructed above. The most disruptive phase is the roof removal (1 to 2 weeks), during which temporary weatherproofing is installed.
If the ground floor renovation is extensive (new kitchen, bathroom, or layout changes at the same time), families with young children often move out for 4 to 8 weeks during the connection phase.
Common Concerns
“Will my existing home handle the weight?”
Most homes can be made to work with targeted structural reinforcement. Full foundation replacement is rare. The structural engineer will specify exactly what’s needed, and we include this in our fixed-price quote.
“Will it look like an addition?”
Not if it’s designed properly. We match materials, rooflines, and proportions so the addition looks like it was always part of the home. Browse our extension gallery to see examples.
“How much backyard will I lose?”
None. That’s the whole point of going up. Your backyard stays exactly as it is.
Second Storey vs Ground Floor Extension
- Choose second storey if you want to keep backyard space, gain views, or your block’s setbacks limit ground floor expansion
- Choose professional home extensions if budget is a priority, your block is generous, or you prefer single-level living
Many of our clients combine both: a ground floor extension for the kitchen and living areas, plus a second storey for bedrooms. If you’re also weighing up a full rebuild, see our renovate or rebuild comparison. This gives you the best of both options.
Why Dura Group for Your Second Storey Addition
- Fixed-price contracts covering all structural work, approvals, and fit-out
- Structural engineering included in the quote, not as an extra
- No material markups on any finishes or fixtures
- 25+ years building second storey additions across the Sutherland Shire
- Mark manages every project from design through to handover
See second storey projects we’ve completed in Menai house additions, Illawong home extensions, Engadine house additions, Barden Ridge house additions, and Caringbah home extensions.
Contact Dura Group today or call Mark on 0424 665 793.
For more about how we can help, visit our home extension by Dura Group page.
Frequently Asked Questions
How much does a second storey addition cost in Sydney?
A second storey addition in Sydney costs $250,000 to $600,000+ depending on size and complexity. Expect to pay $4,500 to $7,000 per square metre fully fitted out.
How long does a second storey addition take?
Construction takes 16 to 30 weeks. Add 8 to 16 weeks for design and council approvals before building starts.
Can my house support a second storey?
Most houses can, with structural reinforcement. A structural engineer assesses your home during the planning phase and specifies any work needed. We include this in our fixed-price quote.
Do I need to move out during construction?
Usually not. The ground floor stays liveable while the upper level is built. The most disruptive phase is the 1 to 2 week roof removal period.
Will a second storey addition need council approval?
Yes, always. Our guide to DA vs CDC approvals in NSW explains which pathway applies. We handle the full approval process for you.
Mark Dura is the founder of Dura Group Building & Renovations, a licensed builder (Lic 381531C) with 27+ years of experience in residential renovations, home extensions, and knockdown rebuilds across Sydney. Mark oversees every project from design through to completion.
