Basement Living
Extra bedrooms or a family room, right up to a full lower level under the house. If you're reworking a space that's already there, our basement remodeling work can take it from there.
Excavation · Sydney, NSW
Under House & Basement Excavation in Sydney
Short on space but love your block? For professional underhouse excavation in Sydney, Substructure Solutions manages everything from compact storage excavations to full basement digs. We plan around your ground and access, then build it out in careful stages.
- Licensed NSW Builder
- 10+ Years Below Ground
- Transparent Pricing
The basics
What Is Under House Excavation?
Under house excavation is the process of digging out the ground beneath or beside an existing home to create usable space, without changing the building's footprint.
You build down into your own block rather than out into the yard or up with a second storey. It's the dig, not the whole build. Excavation removes the soil and rock, then the structure and waterproofing follow before any fit-out.
On most jobs you can stay in the house while we work, because the dig is staged and your services stay connected. Many people choose under house excavation because it adds space without giving up the garden.
Possibilities
What the Excavated Space Can Become
Once the ground is out, the space is yours to shape. These are some of the most popular ways Sydney homeowners put it to use.
Garage or Parking
Off-street parking on a block with none, which adds value on tight streets. Our basement garage builds cover the ramps and structure that come with it.
Storage & Utility
A dry, out-of-the-way level for storage or a workshop, with room for services like hot water and pumps. It's a simple way to free up room upstairs.
Cellar, Gym or Studio
Purpose-built rooms that suit the steady temperature below ground. Take a look at our underground room builds for ideas.
Shelters & Safe Rooms
Some households use the space for security. That might be an underground panic room or an emergency shelter underground built to protect the family.
Methods
Under House & Basement Excavation Methods
Every dig is different, and the equipment we bring depends on what's under your floor and how we can get to it. These are the methods behind most of our basement excavation work.
01
Tight-Access & Mini Excavators
Compact machines fit through side access or a doorway and work under low head height. Where clearance is tight, we can take the canopy off. The smaller the access, the smaller the machine.
02
Rock Sawing & Hammering
Much of Sydney sits on sandstone, so we cut it with a diamond rock saw and break it up with a hydraulic hammer. It comes out in controlled sections. A home on solid rock is often the easier case, and it may need little or no underpinning.
03
Spoil Removal & Site Management
Every cubic metre dug out has to leave the site, often through the same tight access. We load and cart the spoil away while keeping dust under control. All work runs within council-approved hours, and we plan truck access so your street isn't blocked for long.
04
Shoring, Retention & Services
Where the dig runs deep or close to a boundary, temporary shoring holds the surrounding soil. Before any machine starts, we locate and protect underground drainage and plumbing, along with any electrical lines.
Methods at a Glance
| Method or equipment | What it does | When it is used |
|---|---|---|
| Tight-access & mini excavators | Dig under low clearance and narrow access | Under an existing home with side access only |
| Rock sawing & hammering | Cut and break Sydney sandstone in sections | Rock ground, common across Sydney |
| Spoil removal | Load and cart excavated material off site | Every dig, and harder with tight access |
| Shoring & retention | Hold the surrounding soil during the dig | Deep digs, or near footings and boundaries |
| Service location | Find and protect drainage and utilities | Before every excavation |
Local ground
Excavating in Rock & Tight-Access Sites
Sydney sites are often rocky or tight on access, and both change how a dig runs. Most under house excavation Sydney jobs involve at least one of the two.
Rock. Sandstone is removed by saw and hammer rather than scooped out, which is slower but keeps the ground stable. On many rock sites, underpinning may not be needed at all.
Tight access. Where the only way in is a side path or a garage door, we scale the machine down to match. The dig is then staged to protect the house and your neighbours. Planning around this local ground is a big part of our basement excavation projects in Sydney, and it's the difference between a smooth dig and a stalled one.
Footings
Foundation Excavation & Underpinning
Foundation excavation digs around and beneath existing footings, either to form new footings for the build or to underpin a foundation that has moved.
When excavating under house footings, we sometimes find the reason a floor was sloping or a wall was cracking. That's a foundation problem rather than a space problem.
Where it happens, the fix is underpinning, and we can carry it out as part of the same dig.
Pricing
How Much Does Under House Excavation Cost in Sydney?
No two digs cost the same, because the price follows the ground and the access. The cost of under house excavation Sydney homeowners can expect comes down to a few key factors, listed alongside.
A real figure comes from a site assessment. We read the ground and the access, then give you a scope and a price before any work starts. Getting the dig right early also helps keep the rest of your build on budget. Book a site assessment.
Approvals
Do You Need Council Approval to Excavate Under a House?
It depends on the scope. Digging out a basement or a new level usually needs a Development Application and a structural engineer, while smaller works may not. We'll help you confirm the right pathway, and the NSW Planning Portal explains the options if you'd like to read up.
Why Substructure Solutions
Why Choose Substructure Solutions for Under House Excavation
Digging beneath Sydney homes has been the core of our underground construction work for more than a decade. We take the same care with basement excavation Sydney homeowners need for a storage room as we do for a full lower level.
10+ Years Experience
More than ten years below ground has shown us how Sydney sandstone and clay behave once the machines start. Every dig we plan draws on that experience.
Licensed Builder
Every job is led by a licensed NSW builder who stays involved from the first inspection to handover. You'll always know who to call with a question.
Transparent Pricing
You'll get a clear scope and price before any work starts. If something changes on site, we'll talk it through with you before going ahead.
Completed Package
We don't just dig and leave. Once the ground is out, we can build the full basement through our basement construction service, including wall removal upstairs if you're opening up the layout. It saves you coordinating a second contractor.
Our process
How We Build Your Basement
Whether it's a small storage dig or a full lower level, every project follows the same steps. It keeps your home supported and the site under control.
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Inspect
We read the ground and the access, then locate your services. This tells us what's possible before you commit to anything.
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Plan
We set the machine size and spoil route, along with any retention the dig needs.
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Excavate
The ground comes out in staged sections, by digger in soil and by saw and hammer in rock. Each section is checked before the next one starts.
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Clear
Spoil is loaded and carted off site within council hours.
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Prep
We bring the base to level, ready for footings or a slab. Any foundation excavation for new footings happens at this stage too.
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Handover
We continue straight into the build, or hand over a clean, level base for your own builder. Either way, you'll get the paperwork for the work we've done.
Our work
Our Recent Projects
Testimonials
What Our Clients Say
★★★★★
Completely satisfied with the basement addition to our premises. On time and on budget, highly recommend Sarkis and his team.
★★★★★
A great and reputable service! Sarkis was great and we had great security with his supervision under pressure he kept us informed and reassured. Would definitely recommend to anyone needing underground basement solutions.
★★★★★
Sarkis was warm and friendly but also genuine, very responsive and professional from the get go. It gave me a lot of peace of mind to have him managing the project. Would recommend to anyone needing a trustworthy, knowledgeable person to deal with basement issues.
FAQs
Under House Excavation FAQs
Can I stay in the house during excavation?
On most jobs, yes. Excavating under house floors is done in stages and your services stay connected, so daily life can carry on above. Expect some noise and vibration during rock work.
Can you excavate through rock?
Yes. Sandstone is common across Sydney, and we cut it with diamond saws before breaking it out with hydraulic hammers. It's slower than digging soil, but the ground stays stable.
How much clearance or access do you need?
Less than you might think. Mini excavators can fit through a side path or a doorway and work under low head height. Very low or narrow sites may need some hand digging at the start. We'll confirm the right machine for your site during the inspection.
Do you build the basement after excavating, or dig only?
We can do either. We'll hand over a clean base for your own builder, or take the project all the way through. Many clients choose the full package so one team handles the basement excavation and the build.
How much does under house excavation cost?
The price of under house excavation depends on the volume of the dig and the ground conditions, along with access for machines and spoil. We'll give you a clear scope and price after a site assessment.
Do I need council approval to dig under my house?
Often, yes. A basement or new level usually needs a Development Application and a structural engineer's design, while minor works may not. We'll help you check before any work begins.
How long does under house excavation take?
Smaller digs can take a few weeks, while a full basement through rock takes longer. Approvals add time up front, so we'll give you a realistic timeline with your quote.
Book Your Site Assessment
Ready to see what's possible beneath your floor?
Get in touch to book a site assessment and a clear plan for your dig.