A new upper level on a single-storey home
CompletedA second storey we built in 2024 on a single-storey home in the Illawarra. These photos were taken during the build, before the front was clad.
Second-Storey Extensions in Wollongong & the Illawarra
Get a free quoteIf your block is small or steep, or you simply do not want to lose the backyard, the answer may be up. A second-storey extension, also called a first-floor addition or top-floor extension, adds bedrooms, a parents’ retreat or a whole new living level on top of your existing home.
It is a bigger job than building out. The roof usually comes off, an engineer has to confirm the house below can carry the new load, and the staircase has to fit somewhere sensible. We look after it end to end, from design to council approval and build.
We are based in Dapto, and our three directors grew up in the Illawarra. We build across Wollongong and the wider Illawarra, Shellharbour, the Kiama region, Wollondilly and the Southern Highlands, as far south as Berry.
What a second storey can add
A main bedroom suite
A parents’ retreat with an ensuite and walk-in robe upstairs, away from the living areas.
More bedrooms
Extra bedrooms and a bathroom for a growing family, without giving up the yard.
Upstairs living with a view
A living room, rumpus or study with a balcony. On many Illawarra blocks, going up is the way to get the view.
A full upper level
Kitchen, living and bedrooms upstairs, with the ground floor reworked underneath.
A partial second storey
Building over one part of the house only, such as one wing, which can be simpler and less disruptive.
Or build out instead
If you have the yard for it, a ground-floor extension is usually simpler and cheaper per square metre.
Home extensionsOur work
Our second-storey work
Photos from our 2024 second-storey work, and plans from our current jobs.
Roof off: where a second storey starts
CompletedA 2024 second-storey job from the air. The back section of the roof is off, with scaffolding and edge protection around the house: the stage before the new upper floor is framed.
Oak Flats: a new upper level
Design stagePlans for a second storey on an existing home in Oak Flats: a main bedroom with ensuite and walk-in robe, an upstairs kitchen, living and dining area, and a balcony.
A two-level addition joined to an existing house
Design stageA two-storey addition beside an existing house on a sloping block, joined to it by a new metal roof.
OUR APPROACH
Our 3-Step Project Management Framework
From initial consultation to key handover — a proven process that gives you complete clarity and control at every stage.
Discovery & Design
We visit your site to understand your vision, then engage with our draughtsmen to get your plans drawn—ensuring every detail reflects what you want to build.
- On-site consultation
- Vision alignment
- Professional plan drafting
The Specification
A second visit to review a fully broken-down specification list and your initial timeline projection. Every material, fixture, and finish—documented and transparent.
- Detailed specification list
- Material selections
- Timeline projection
Finalization Roadmap
We finalize all adjustments to your project scope and provide an updated, transparent specifications sheet, a clear start date, and a defined timeline for your build.
- Refined specifications confirmed
- Start date projection
- Contractual transparency
Step by step
How a second storey is built
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Site visit and engineering check
We visit the house, and an engineer checks whether the structure below can carry a new level.
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Design
We work with our draughtsmen on the plans, including where the stairs go and how the new roofline sits.
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Approval
A CDC or a DA, plus a BASIX certificate and any bushfire or flood reports the block needs.
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Contract and insurance
You sign a written contract with the specification and start date in it. For work over $20,000 you also receive the home building insurance (HBCF) certificate before any deposit is paid.
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Preparation
Asbestos removal if any is present, temporary supports, and moving any services that are in the way.
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Roof off and new floor
The old roof comes off over the area being built on, the new floor structure goes in, and the house is covered to keep the weather out.
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Frame, roof and lock-up
Upper walls, the new roof, windows and cladding.
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Stairs and fit-out
The stair opening is cut through, services are connected, then linings, wet areas, joinery and painting.
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Final inspection and handover
The certifier carries out the final inspection and issues an occupation certificate, and we walk through the finished work with you.
Can my house take a second storey?
Before anything is designed, a structural engineer needs to look at what is already there. These are the questions they answer:
Footings
Older homes often sit on footings sized for one storey. They may be fine, or they may need underpinning or new piers to carry the extra load.
Walls and frame
In brick-veneer and timber-framed houses, new posts or steel beams often carry the upper floor down to new footings, rather than relying on the existing walls.
Roof and ceiling
The existing roof usually comes off. Ceiling joists are rarely big enough to become a floor, so new floor joists or a steel frame go in above them.
Where the stairs go
A staircase takes floor space on both levels and must meet the National Construction Code rules for step height, depth and balustrades. Finding the right spot is often the hardest part of the design.
Asbestos
Many homes built before 1990 have asbestos in the eaves, wall sheeting or roof space. It has to be identified, and removed safely if it will be disturbed, before the roof comes off.
Planning matters too: the overall height, overshadowing and privacy for the neighbours, and whether the street is in a heritage conservation area.
Approvals
Do I need a DA for a second storey?
Not always. Some first-floor additions can be approved as complying development (a CDC) under the NSW Housing Code, if the lot and the design meet its standards. Those include the 8.5 m height limit, side setbacks that increase for upper levels, and privacy rules for windows and balconies. Others need a development application to council, especially on narrow lots, in heritage areas, or where the design falls outside the code.
A BASIX certificate is needed for alterations and additions costing $50,000 or more, which covers almost every second storey.
Things that can affect your approval
- Bushfire-prone land: a bushfire attack level (BAL) assessment sets the construction standard.
- Flood-affected land: new floor levels may need to sit above the flood planning level.
- Heritage items and conservation areas: usually a DA, with limits on how the addition looks.
- Steep or unstable land: council may ask for a geotechnical report.
- Sewer mains and easements: building over or close to them needs the water authority’s approval (Sydney Water across most of our area).
Local planning rules differ between councils, including Wollongong, Shellharbour and Kiama, so the right approval path is worked out for your block at the design stage.
Cost
What does a second storey cost?
The price comes from the plans and specification. Per square metre, building up usually costs more than building out, and these are the reasons:
Structure
Engineering, steel, and new footings or underpinning to carry the upper floor.
The roof
Removing the old roof, protecting the house while it is off, and building the new one.
The staircase
The stair itself, and the floor space it takes downstairs.
Services
Running plumbing, power and air conditioning upstairs, and sometimes a new switchboard.
Access and scaffolding
Scaffolding around the house for the frame and roof stages, and a crane for steel or trusses on tight sites.
Hidden conditions
Asbestos, old wiring or structural surprises in the existing house.
Finishes
Windows, balconies, bathrooms and the quality of fixtures.
Where you live meanwhile
Not a building cost, but part of the budget if you move out while the roof is off.
You will see a fully broken-down specification list before anything is signed, so you know exactly what is included.
Book a free consultationPeace of mind
Your protections under NSW law
A written contract
Residential building work over $5,000 (including GST) needs a written contract, and the deposit can be no more than 10% of the contract price.
Home building insurance
For work over $20,000, the builder must give you a Home Building Compensation Fund (HBCF) certificate before asking for a deposit or starting work. It protects you if the builder dies, disappears or becomes insolvent.
Statutory warranties
Building work carries a warranty of six years for major defects and two years for all other defects.
Inspections and sign-off
The certifier inspects approved work at key stages and issues an occupation certificate before the new space is used.
These come from the Home Building Act 1989 and the NSW planning laws.
What our clients say
“Fantastic experience from start to finish. The team was professional, reliable, and delivered high-quality workmanship. Communication was excellent throughout the project, and the finished result exceeded our expectations. Highly recommend Brad and his team to anyone looking for quality work and great service.”
5.0 on Google
FAQs
Second-storey extensions: common questions
Can my house take a second storey?
Many houses can, but a structural engineer needs to check the footings, walls and frame first. Some homes need new piers or steel posts to carry the new floor, and for a few, building out makes more sense. That check comes before the design, so plans are not drawn for something that cannot be built.
Is it cheaper to build up or out?
Building out is usually cheaper per square metre. Building up costs more because of the structure, the roof and the stairs, but it keeps your yard, and on a small or steep block it may be the only way to add real space.
Do we have to move out during a second-storey extension?
Most families move out for part of the build, mainly while the roof is off and the ceilings below are opened up. Some designs keep part of the house usable. It is worth planning this at the design stage so you can budget for it.
Can a second storey be approved as complying development (CDC)?
Sometimes. A first-floor addition can be approved as a CDC under the NSW Housing Code if the lot and design meet its standards, including the 8.5 m height limit, upper-level setbacks and privacy rules. Otherwise it needs a development application to council.
How long does a second-storey extension take?
It depends on the design, the approval route and the weather, so there is no standard timeframe. Once the design is settled you get a timeline projection with the specification, then a confirmed start date and build timeline before you sign.
What happens to the existing roof?
It is usually removed, either over the whole house or just the part being built over. The house is protected with temporary weather covers until the new structure and roof are on.
Where will the stairs go?
Usually near the centre of the house or off the main living area, where the stair takes the least useful space downstairs. It must meet the National Construction Code rules for step height, depth and balustrades, and it is one of the first things settled in the design.
Which areas do you build second storeys in?
We build across Wollongong and the wider Illawarra, Shellharbour, the Kiama region, Wollondilly and the Southern Highlands, as far south as Berry.
Other ways we can help
Where we build
We build across Wollongong and the wider Illawarra, Shellharbour, the Kiama region, Wollondilly and the Southern Highlands, as far south as Berry.
- Wollongong
- Illawarra
- Shellharbour
- Kiama
- Wollondilly
- Southern Highlands
- Berry
get in touch
Connect with our team for a free consultation with our experienced builders.