Second Storey Extension Costs in Sydney
A second-storey extension in Sydney typically costs between $280,000 and $420,000 for a full-width addition to a single-storey home. The cost depends on the footprint size, the number of rooms added, the structural requirements of the existing ground floor, and the finish level selected. The following ranges reflect Pearson Industries project data from 2024–2025 in the Hills District and North Shore, where we complete the majority of our second-storey work.
| Project Scope | Typical Cost Range | Build Time |
|---|---|---|
| Partial second storey (1–2 bedrooms, 60–80m²) | $180,000 – $260,000 | 16–20 weeks |
| Full second storey addition (3–4 bedrooms, 100–140m²) | $280,000 – $420,000 | 20–28 weeks |
| Full second storey with ensuite and retreat (140–180m²) | $380,000 – $520,000 | 24–32 weeks |
These costs include structural engineering, all construction works, internal fit-out (flooring, joinery, painting, electrical, plumbing), and project management. They do not include council or certifier fees, which typically range from $3,000 to $15,000, or the cost of temporary accommodation during construction if required. Pearson Industries provides fixed-price contracts — your quoted price does not change unless you alter the scope after signing.
CDC or DA: Which Approval Do You Need for a Second Storey Addition?
Most second-storey extensions in Sydney can be approved via either a Complying Development Certificate (CDC) issued by a private certifier, or a Development Application (DA) lodged with your local council. Choosing the right pathway can save you 8–12 weeks of approval time and several thousand dollars in fees. Pearson Industries assesses your CDC eligibility at the free consultation stage at no charge.
| CDC (Complying Development) | DA (Development Application) | |
|---|---|---|
| Who approves it | Private accredited certifier | Local council |
| Typical timeline | 10–20 business days | 8–16 weeks |
| Typical cost | $2,500 – $6,000 certifier fee | $3,000 – $15,000 council fees |
| Neighbour notification | Not required | Usually required (14–28 days) |
| Best for | Standard suburban lots meeting SEPP criteria | Corner lots, heritage areas, irregular sites |
CDC Eligibility for Second Storey Extensions
Under the State Environmental Planning Policy (Exempt and Complying Development Codes) 2008 — the SEPP Codes — a second-storey extension qualifies for CDC approval if the site meets all of the following: the lot is at least 200m² in area, the height of the building does not exceed 8.5m at any point, total floor space ratio does not exceed the applicable threshold, setbacks from the primary street and rear boundary comply with the code, and the lot is not within a heritage conservation area, a foreshore area, or a flood planning area. Corner lots, properties in heritage conservation areas, and lots in certain bushfire zones must generally use the DA pathway regardless of size.
The Low and Mid Rise Housing SEPP, which commenced 21 March 2026, has expanded CDC eligibility for certain medium-density housing types within 400m of train stations, but this applies primarily to dual occupancy and multi-dwelling housing, not to single-dwelling second-storey additions which remain governed by the SEPP Codes criteria above.
Second Storey Extension Overview
Elevate Your Home with Pearson Industries. Thinking about adding more space to your home without compromising your backyard or garden? A second-storey extension is a perfect solution. At Pearson Industries, we specialise in creating beautiful, functional, and structurally sound second-storey additions that blend seamlessly with your existing home.
Why Choose Pearson Industries for Your Second Storey Extension?
Expert Design and Planning: Our experienced design team works closely with you to create a second-storey extension that complements your home’s architecture and meets your family’s needs. We provide detailed plans and 3D renderings to help you visualise the transformation.
Quality Construction: Pearson Industries prides itself on high-quality craftsmanship. We use the finest materials and the latest construction techniques to ensure your second-storey extension is built to last. Our attention to detail ensures that every aspect of the construction meets our exacting standards.
Seamless Integration: One of our primary goals is to make your second-storey extension look like it’s always been part of your home. We match the style, materials, and finishes to create a cohesive and harmonious look.
Project Management: From the initial consultation through to the completion of your extension, our dedicated project managers oversee every detail. We handle all permits, inspections, and logistics to ensure your project runs smoothly and is completed on time and within budget.
Increased Value: Adding a second story to your home not only provides additional living space but also significantly increases your property’s value. A second-storey extension typically adds 20–30% to the resale value of a Sydney home, according to data from property valuers across the Hills District and North Shore. It is a smart investment that offers both immediate and long-term benefits.
Our Second Storey Extension Services Include
Initial Consultation and Design: We begin with a comprehensive consultation to understand your vision, needs, and budget. Our design team then creates detailed plans and 3D models to illustrate the proposed extension.
Planning and Approvals: We manage all aspects of planning and approvals, working with private certifiers and local councils to ensure your project complies with all regulations and codes. We advise on the fastest and most cost-effective approval pathway for your specific site.
Construction and Building: Our skilled builders and tradespeople bring the design to life, constructing your second-storey extension with precision and care. A dedicated project manager is assigned to your build and provides weekly photo updates throughout construction.
Interior and Exterior Finishing: From flooring and cabinetry to painting and exterior cladding, we handle all finishing touches to ensure a polished and complete look.
Project Completion and Handover: Once the extension is complete, we conduct a thorough inspection and walk-through with you to ensure everything meets your expectations. You receive all certificates, warranties, and maintenance documentation at handover.
A Recent Second Storey Extension — Castle Hill, NSW
In early 2025, Pearson Industries completed a full-width second-storey addition for a client in Castle Hill (Hills District). The project added four bedrooms, two bathrooms, and a parents’ retreat over an existing single-storey brick-veneer home. The existing roof was removed, the ground-floor walls were reinforced with steel posts to carry the new load, and the entire second storey was framed, sheeted, and tiled in 22 weeks from the day the CDC was issued. External cladding was fibre cement panels painted to match the existing brickwork colour, maintaining a consistent street-facing elevation. Final cost: $385,000 including all fit-out. The client, Rob from Castle Hill, noted: “Pearson Industries exceeded our expectations. The team was professional, communicative, and dedicated to making sure every detail was perfect. We now have the extra space we needed, and it looks fantastic.”
Suburb Areas for Second Storey Extensions
Pearson Industries carries out second-storey extensions throughout Greater Sydney. We regularly work in:
- Castle Hill, Baulkham Hills, Kellyville — Hills District
- Chatswood, Gordon, Killara, Lindfield — Upper North Shore
- Manly, Dee Why, Brookvale — Northern Beaches
- Parramatta, Westmead, Merrylands — Parramatta
- Ryde, Meadowbank, Eastwood — Ryde
- Hornsby, Wahroonga, Pymble — Ku-ring-gai
- Neutral Bay, North Sydney, Cremorne — Lower North Shore
- Mosman, Balmoral, Spit Junction — Mosman
Frequently Asked Questions — Second Storey Extensions
How long does a second storey extension take in Sydney?
A typical second-storey extension project in Sydney takes 20–28 weeks from the day construction begins, depending on the size of the addition and the complexity of the structural work. Approval (CDC or DA) adds additional time before construction starts: CDC approval typically takes 2–4 weeks; DA approval typically takes 8–16 weeks. Pearson Industries provides a fixed construction timeline in the contract. Delays due to adverse weather are the only variation we apply without prior agreement.
Do I need to move out during a second storey extension?
For a full second-storey addition, you will generally need to vacate for at least the framing and roofing phase (typically 4–8 weeks) as the existing roof is removed and the new structure is exposed to weather. We install temporary waterproofing as fast as possible to reduce your time out of the home. For partial second-storey additions where only part of the roof is opened up, some clients are able to remain in a section of the house with appropriate safety barriers. We advise on the specific scenario at consultation.
What is the best way to add bedrooms to a Sydney home?
A second-storey extension is typically the most efficient way to add bedrooms to a Sydney home if the block is too small for a rear extension or if you want to preserve backyard space. It provides the largest amount of new floor area for the cost compared with any other addition type. Ground-floor additions to the rear are also viable if the property has sufficient rear setback. Pearson Industries compares both options and provides a cost-per-square-metre estimate for each at the consultation stage so you can make an informed decision.
Get a Free Second Storey Extension Quote
Contact Pearson Industries for a free, no-obligation quote on your second-storey extension project. We serve all of Greater Sydney and provide a written feasibility assessment at the initial consultation at no charge. Call us on 0450 677 357, email info@pearsonindustries.com.au, or use our online quote form.
NSW Builder Licence 292515C | 700+ completed projects | Serving all of Greater Sydney
