Specialists in Basement Extensions & Underground Construction – Sydney

WELCOME

Substructure Solutions specialises in complex underground construction across Sydney. We design and build basement extensions, underground rooms, and bunkers, and carry out professional wall removal, structural repairs, and all forms of underpinning—including concrete underpinning and foundation stabilisation. Whether you're planning under house excavation, reinforcing your structure, or creating a secure underground safe room, we deliver safe, tailored solutions built to last

Underground Construction Done Properly

We help Sydney homeowners and builders make better use of the space below their properties. Our work includes everything from expanding living areas to stabilising foundations and building custom-designed, fire-safe underground bunkers. Every project is handled by a licensed builder with more than a decade of hands-on experience in structural and subsurface construction.

If you need to add space, increase safety, or fix a structural issue without cutting corners, we’ll help you plan the right solution and execute it carefully.

About Us
Testimonials

TESTIMONIAL

★ ★ ★ ★ ★

Sarkis successfully repaired my leaning pier under the house. His expertise was evident throughout the job. He finished the job in record time. To my amazement! He is brilliant!!! I had been worrying about the pier for some time b4 I called him. Don’t bother calling anyone else! Satisfied customer 100 per cent.

Bellywub69

★ ★ ★ ★ ★

Sarkis from Substructure Solutions recently completed a sizeable repair job for me. He was professional and easy to work with starting from the initial assessment and quoting, through to completion of the job. It was completed on time and on budget, and he was always quick to address my many questions and concerns along the way. I should also mention that he went above and beyond when he helped to secure a shed that threatened to blow away in a mini-gale – quite unrelated to the contracted job. I am very happy to recommend Sarkis and his team.

Chris Wickremasinghe

★ ★ ★ ★ ★

Top bloke, transparent with the pricing. Came early, did the job (added three support stumps) and finished early. Easy to work with. Definitely would work with again in the future.

Chris

OUR SERVICES

Modern underground bunker interior in Sydney featuring industrial-grade ventilation systems, corrugated steel walls, and secure reinforced access.

Underground Bunkers

Our underground bunkers are built for strength, longevity, and peace of mind. Use them as an emergency shelter underground, a fire-safe storage room, or a secure backup space with controlled access.

Learn More

Underground Rooms

We build fully enclosed underground rooms that are secure, insulated, and private. From underfloor wine cellars to home offices, we create spaces that fit your needs and your footprint.

Learn More

Basement Extension

Expand your home with a functional, high-quality basement extension. Ideal for extra bedrooms, home gyms, storage areas, or multi-use spaces. Designed to integrate seamlessly with your existing home, without compromising structure or safety.

Learn More

Underpinning and Structural Repair

We specialise in underpinning Sydney properties affected by subsidence, shifting soils, or unstable foundations. Our concrete underpinning techniques are designed to restore stability and protect your home long-term.

Learn More

Wall Removal

Planning to open up your layout? We carry out safe, compliant wall removal for both structural and non-structural walls. Reinforcements, engineering, and approvals all managed from start to finish.

Learn More

Foundation Stabilisation and Concrete Sinking Repair

We diagnose and fix signs of foundation movement, from cracked walls to sunken floors. Our concrete sinking repair and structural solutions are tailored to your site, using proven methods to restore integrity and prevent future damage.

Learn More

Substructure Solutions isn’t a general builder trying to do it all—we focus specifically on underground construction and structural work, including concrete underpinning. That means we understand the challenges of digging, reinforcing, and building below ground. From the first site inspection to the final handover, we approach each project with care, clarity, and the technical know-how to get it done properly.

Why Work With Substructure Solutions?

Over 10 years of specialised structural and underground experience

We’ve spent more than a decade focused on complex construction beneath homes and buildings across Sydney. This isn’t side work—it’s what we do, day in, day out.

Licensed builder with expertise across excavation and construction

Every project is managed by a qualified, licensed builder. We don’t outsource the hard stuff. We show up, we do the work, and we stand by the results.

Local knowledge of Sydney soil, planning rules, and site challenges

From rock-heavy ground to narrow access sites, we know how to work around Sydney’s trickiest conditions and still deliver a safe, solid result.

Safety-first methods with full compliance and documentation

We follow the correct procedure, not shortcuts. Every build meets safety standards, structural codes, and council requirements. We also help manage approvals where needed.

No sales spin—just straightforward advice and reliable work

You won’t get vague promises or inflated quotes. We give honest, practical advice about what’s possible, what it costs, and how to do it right.

We’ve built our reputation by showing up on time, doing the job properly, and fixing problems others won’t touch. If you’re after a team that knows what they’re doing and doesn’t muck around, we’re ready to help.

Built for Safety. Designed to Last.

From complex basement extensions to urgent structural repairs, we bring practical solutions to complicated problems. We don’t overpromise or outsource—we plan thoroughly, build with care, and leave you with a structure you can rely on for years to come.

Ready to get started? Contact Substructure Solutions for a no-obligation quote and expert advice tailored to your site and your project.

HAVE A QUERY