A ground floor extension is one of the most practical ways to add living space to your home without building upward or moving house. It pushes the footprint of your home outward, usually at the rear or side, and can add anything from a single room to a complete new kitchen, living, and dining area. Our guide to renovating in the Inner West covers this in detail.
At Dura Group, ground floor extensions are one of our most requested services across the Sutherland Shire. This guide covers what’s involved, what it costs, and what you need to know before starting.
What Can a Ground Floor Extension Include?
The scope depends on your needs and your block. Common ground floor extensions include:
- Open-plan kitchen, dining, and living: The most popular option. See our kitchen renovation cost guide for the fit-out component. Removes the back wall of the house and extends into the backyard to create a modern, open living space with indoor-outdoor flow
- Extra bedroom or rumpus room: A single-room addition, often for growing families or to create a home office
- New bathroom or laundry: Added alongside a larger extension, or as a standalone addition
- Sunroom or enclosed alfresco: A lighter-weight addition that adds usable space without the full cost of a structural extension
Ground Floor Extension Costs
In Sydney, ground floor extensions typically cost $3,500 to $6,000 per square metre fully fitted out. That includes structure, fit-out, approvals, and project management. For current rates across all project types, see our Sydney building costs guide.
For a more detailed cost breakdown, see our full home extension cost guide. Or browse our Sutherland Shire builders page for an overview of our services.
- Small (15 to 25m2): $150,000 to $200,000
- Medium (25 to 40m2): $200,000 to $300,000
- Large (40m2+): $300,000 to $400,000+
The Ground Floor Extension Process
1. Initial Consultation and Site Assessment
We visit your home, discuss what you want to achieve, and assess the site. This includes checking boundary setbacks, easements, fall of the land, and access for construction. We identify any potential issues early so there are no surprises later.
2. Design and Documentation
Working with our design and build team, we develop plans that meet your needs and comply with council requirements. This includes architectural drawings, structural engineering, and BASIX energy assessments.
3. Council Approval
Most ground floor extensions require either a development application service. A CDC is faster (typically 10 to 20 business days) but has stricter size and setback requirements. A DA takes longer (6 to 12 weeks) but allows more flexibility. We handle the entire process and recommend the best pathway for your project.
4. Construction
Once approved, construction typically runs 12 to 20 weeks:
- Weeks 1 to 3: Site preparation, excavation, and footings
- Weeks 4 to 6: Slab pour and framing
- Weeks 7 to 9: Roofing, windows, and external cladding
- Weeks 10 to 12: Internal fit-out (plumbing, electrical, plasterboard)
- Weeks 13 to 16: Kitchen/bathroom installation, tiling, painting
- Weeks 17 to 20: Final fixtures, landscaping, and handover
5. Handover
We walk through the completed extension with you, address any items on the defect list, and hand over all compliance certificates and warranties.
Key Considerations for Ground Floor Extensions
Setback Requirements
Sutherland Shire Council (and most Sydney councils) require minimum setbacks from side and rear boundaries. Typically 900mm from the side boundary and 3 to 6 metres from the rear. These setbacks limit how far you can extend. We check these early in the planning process.
Floor Space Ratio (FSR)
Every property has a maximum floor space ratio set by council. This determines how much total floor area you can have relative to your block size. If your home is already close to the FSR limit, there may be limited scope for extension.
Stormwater and Drainage
Extending the footprint of your home means more roof area and more hardstand, which increases stormwater runoff. Council requires a stormwater management plan for most extensions. This can involve new drainage pits, pipes, or on-site detention tanks.
Connecting Old and New
One of the biggest challenges in a ground floor extension is making the new section feel like it belongs with the existing home. Matching rooflines, floor levels, ceiling heights, and materials takes careful planning. This is where experience matters. At Dura Group, we’ve delivered hundreds of extensions where you can’t tell old from new.
Ground Floor Extension vs Second Storey
- Ground floor: Lower cost per m2, less structural complexity, but reduces backyard space
- our extension service: Keeps your backyard intact, but costs more due to structural reinforcement, scaffolding, and roof rebuild
The right choice depends on your block size, backyard priorities, and budget. If you’re also weighing up a full rebuild, our renovate or rebuild guide compares all options. If you have a generous block and want to keep costs down, ground floor is usually the way to go. If backyard space is important (especially with kids), going up makes more sense.
For a detailed walkthrough of going up, see our second storey extension guide.
Why Dura Group for Your Ground Floor Extension
- Fixed-price contracts so you know the full cost before we start
- All approvals handled from DA/CDC to occupation certificate
- No material markups on finishes and fixtures
- 25+ years experience extending homes across the Sutherland Shire
- Mark manages every project personally
See our extension gallery for recent projects, or check out extensions we’ve completed in Menai house additions, Engadine home extensions, and Caringbah house additions.
Contact Dura Group today or call Mark on 0424 665 793.
For more about how we can help, visit our Dura Group home extensions page.
Frequently Asked Questions
How much does a ground floor extension cost in Sydney?
A ground floor extension in Sydney costs $150,000 to $400,000+ depending on size and finish level. Expect to pay $3,500 to $6,000 per square metre fully fitted out.
Do I need council approval for a ground floor extension?
Yes. Most extensions require a DA or CDC. Our guide to DA vs CDC approvals in NSW explains the key differences. We handle the full approval process for you.
How long does a ground floor extension take?
Construction takes 12 to 20 weeks. Add 8 to 16 weeks for design and council approvals before construction starts.
Will a ground floor extension add value to my home?
Yes. A well-designed extension that adds functional living space typically adds more value than it costs. Open-plan kitchen/living extensions are particularly strong for resale.
Can I live at home during a ground floor extension?
In most cases, yes. The new section is built separately before being connected to the existing home. There will be 1 to 2 weeks of disruption when walls are opened up, but it’s usually manageable.
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.
