Home Extensions Northern Beaches | Structural Steel & Load-Bearing Walls

Home extension under construction with structural timber framing, Northern Beaches

Why Bark

Structural Work, Done Once

Extensions are the work most chippy teams either won't touch or quote so high they hope you say no. We don't shy away from the structural side. Steel beams, load-bearing wall removal, second-storey additions, full ground-up extensions. Coby and Bill have run extensions across the Northern Beaches for years.

The risk on an extension is the gap between what's quoted and what's delivered. We close that gap by quoting in detail, locking the price, and running every trade ourselves. You get one builder, one timeline, one number to call when something needs sorting.

HBCF insurance, public liability, contract works cover. Paperwork part of the build, not an afterthought.

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What We Build

Extensions and Structural Work

Single-Room Extensions

Adding a bedroom, study or master ensuite within the existing footprint or as a small addition. Typically 8–25 sqm. Often CDC-approvable.

Rear Extensions

Opening up the rear of the house with a new living, dining and kitchen zone. The most common Northern Beaches reno — older homes with closed-off rear rooms reworked into modern open plan.

Second-Storey Additions

Full upper level over an existing single-storey home. Bedrooms, bathrooms, study, sometimes a deck. Usually a DA project.

Load-Bearing Wall Removal

Removing internal walls to open up floor plans. Structural steel beam, engineering certificate, replastered to match. Typically 1–2 weeks on site.

Structural Steel & Lintels

Steel beams for new openings, lintels over windows and doors, support posts where existing posts won't work. We coordinate the engineer.

Subfloor & Roof Repairs

Older Northern Beaches homes — particularly Manly bungalows and harbourside cottages — often need rotten subfloor timbers replaced or roof rafters strengthened. We handle it.

Approval

CDC vs DA — What You Need

Approval pathway sets your timeline and cost. We confirm which one applies before you spend money on plans.

Exempt Development

Internal-only work that doesn't change the building footprint, alter wet areas, or affect structural elements. No approval needed.

Complying Development Certificate (CDC)

Faster and cheaper than a DA. Single-storey extensions that meet the NSW Codes SEPP standards usually qualify. Approval typically 3–8 weeks via a private certifier.

Development Application (DA)

Required for second-storey additions over height limits, heritage conservation areas, bushfire zones, and foreshore-impact properties. Northern Beaches Council, typically 12–26 weeks.

What This Means for You

If your project qualifies for CDC, you save 2–5 months and several thousand dollars. We tell you up front which path applies after the site visit, often before you've engaged an architect.

Read our full extension cost guide →

How It Works

Site Visit to Handover

Site visit and feasibility. Free site visit. Indicative cost band, approval pathway, structural feasibility, what we'd suggest.
Designer or architect. If you don't have one, we recommend Northern Beaches designers we've worked with. We work to their drawings.
Engineer. Structural engineer engaged for any load-bearing or extension work. We coordinate.
Approval. CDC or DA submitted via private certifier or council. We track and respond to RFIs.
Fixed-price quote. Detailed itemised quote against approved drawings. Number locked, timeline locked.
Build. Site set up, demolition, structural, framing, lock-up, fit-out, finishes, handover.
Defects period. 13-week defects window after handover plus full statutory warranties.

Recent Work

Extensions Across the Beaches

Rotten subfloor + structural rebuild, Manly

100-year-old Californian bungalow. Rotten subfloor timbers replaced, structural framing strengthened, internal walls reworked to open up living. Heritage detailing preserved.

"100 year old Californian bungalow needing rotting timbers replaced. 100 percent professional." — Max H., Manly

Farmhouse renovation + extension, Forestville

100-year-old farmhouse. Internal restructuring, load-bearing walls removed with steel beams, full kitchen and bathroom rebuild, new rear opening to garden.

"Coby and Bill have just finished some renovations on our 100 year old farmhouse and we couldn't be happier." — Tina M., Forestville

Cladding replacement + structural, Avalon

Old cladding stripped back, structural framing checked and reinforced where needed, new modern cladding installed. Three-week build, kept the family in residence.

"Done a fantastic job of replacing the old cladding with brand new modern cladding." — Brooke G., Avalon

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Pricing

Indicative 2026 Extension Costs

Square-metre rates are a useful starting point. Final cost depends on site access, finishes and approval pathway.

Load-bearing wall removal

$4,500–$12,000

Single beam, mid-span, basic re-plaster. Two-storey supports or multi-span beams run higher.

Single-room extension (15–25 sqm)

$80,000–$160,000

$3,500–$5,000/sqm including finishes. CDC pathway where applicable.

Rear extension (40–70 sqm)

$220,000–$420,000

$4,500–$6,500/sqm. Living, kitchen, dining typical scope.

Second-storey addition (60–100 sqm)

$340,000–$650,000

$5,500–$8,000/sqm. Bedrooms, bathrooms, study, optional deck. DA project.

Excludes designer/architect fees, engineer fees, certifier fees, and DA/CDC application fees. Allow 10–15% contingency on top of the build cost.

FAQs

Common Questions

How much does a home extension cost on the Northern Beaches in 2026?

Single-room ground-floor extensions run $3,500–$5,000 per square metre. Rear extensions opening up living, dining and kitchen typically land $4,500–$6,500 per sqm including finishes. Second-storey additions run $5,500–$8,000 per sqm depending on roof structure and access. Most projects sit between $250,000 and $650,000 all-in.

Do I need a DA or CDC for a home extension on the Northern Beaches?

Many compliant single-storey extensions can be approved via a Complying Development Certificate (CDC) under the NSW Codes SEPP — faster and cheaper than a DA. Heritage conservation areas, bushfire zones, foreshore-impact properties, and second-storey additions over height limits typically need a full DA through Northern Beaches Council.

How much does it cost to remove a load-bearing wall in Sydney?

Removing a single load-bearing wall and installing a structural steel beam (with engineering certificate) typically costs $4,500–$12,000 depending on span, ceiling height, and whether services need rerouting. Multi-span beams or two-storey supports run higher.

How long does a home extension take from approval to handover?

CDC approval runs 3–8 weeks. DA approval through Northern Beaches Council typically runs 12–26 weeks. Once approved, build time is 14–30 weeks for ground-floor extensions and 24–40 weeks for full second-storey additions.

Can I stay in my home during an extension?

Most ground-floor extensions allow you to stay onsite, with a sealed work zone and dust protection. Second-storey additions usually require you to move out for 6–12 weeks during the roof removal and frame stage. We tell you up front what's realistic.

Do you handle the engineer, certifier and approvals?

Yes. We coordinate with structural engineers, private certifiers and your designer or architect. You don't chase paperwork — we run that side as part of the build, and we tell you what each stage costs before it kicks off.

What about insurance during the build?

Bark Construction holds Home Building Compensation Fund (HBCF) cover for all jobs over $20,000 as required under NSW law. We also carry public liability and contract works insurance. Certificates are part of the contract pack.

Will an extension affect the value of my home?

Done well, an extension typically returns 1.2–1.8x its cost in equity for established Northern Beaches homes. Layout matters more than square metres — a thoughtful 30 sqm rear extension often adds more value than a 50 sqm bolt-on. We're happy to talk through what your local market rewards.

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Plan Your Extension

Free site visit, indicative cost band, no obligation.

Home Extensions on the Northern Beaches