How much does it cost to build with CJG in New Zealand?

CJG builds from $2,500 per square metre for materials and construction. A granny flat of 60m2 costs from $165,000 all-in. A 150m2 home costs from $390,000 all-in. Typically up to 30% less than the market rate.

How long does CJG take to build a house in NZ?

CJG builds up to 50% faster than standard construction. Manufacturing runs simultaneously with the consent process, saving weeks on every project.

Is CJG Healthy Homes compliant in New Zealand?

Yes. CJG's steel frame and EPS composite panel system is Healthy Homes compliant by design. The closed-cell EPS panel does not absorb moisture, preventing mould. Continuous insulation meets and exceeds NZ Healthy Homes thermal requirements.

Does CJG build granny flats without resource consent?

CJG builds granny flats up to 70m2 which under current NZ government reforms do not require resource consent. CJG manages the building consent process at no extra charge.

Castro James Group | Steel Frame Construction NZ

Our philosophy

The system that makes sense
for New Zealand.

Built better. Priced fairly.

New Zealand's climate demands a construction system built for it. When you look at the materials — steel frame that never rots or warps, EPS composite panel that never absorbs moisture, WPC interior cladding that never needs painting or treatment — they make sense for this country.

When you see the price — up to 30% less than the market all-in rate for superior specification — that makes sense too.

When you see the build time — up to 50% faster than standard construction, with a predictable timeline that does not depend on weather — that makes sense as well.

When you understand that the same system can be extended as your life changes — a granny flat that grows into a family home, a Healthy Homes compliant facility that adapts as your business evolves — that makes sense most of all.

CJG is the construction system New Zealand has always needed. Not a compromise. A better answer.

Why CJG

Every advantage.
No trade-offs.

Every point below follows directly from building with a system engineered for New Zealand's specific conditions. These are not claims. They are consequences.

Engineered for this climate

Built for New Zealand's conditions

Steel frame and EPS composite panel, engineered for humidity, rainfall, seismic activity and temperature variation.

New Zealand asks more of buildings than most countries. High humidity encourages moisture. Heavy rainfall tests weathertightness over decades. Seismic activity requires structural strength. CJG's system was designed to answer all of these challenges simultaneously. Not just on completion day. Every day.

Moisture absorption — EPS closed-cell panel

Zero moisture. Zero mould.

EPS composite panel is closed-cell. It does not absorb water. Ever.

NZ's humidity and rainfall create conditions where moisture finds its way into buildings over time. EPS closed-cell panel does not absorb water regardless of what the weather does. No moisture means no mould, no health risk and no remediation cost. Healthy Homes compliant by design, not by treatment.

STC 50+

Acoustic rating — composite wall assembly

Like entering a recording studio

EPS and WPC together create exceptional acoustic performance.

Step inside a CJG home and the difference is immediate. The EPS structural panel and WPC interior cladding work together as a composite acoustic wall assembly. Street noise, rain, neighbours significantly reduced. For families who value quiet and for businesses needing compliant offices within industrial buildings, this changes everything.

Continuous

Insulation — no thermal bridging

Permanently warm. Permanently efficient.

No thermal bridging, airtight joints. Lower energy bills. Permanently.

EPS insulation runs continuously across the full wall surface with no gaps or thermal bridges. Airtight panel joints eliminate the heat loss that makes many NZ homes cold regardless of how much they are heated. Your home heats faster, stays warm longer, and costs significantly less to run. Every year, for the life of the building.

Expandable

Add rooms, floors or whole wings later

Built to grow with you

Start with what you need today. Extend when you are ready.

A granny flat today can become a full family home when the time is right. A warehouse with one office today can have four offices in three years without touching the core structure. CJG's steel frame system is designed with future extension in mind. Your building is a starting point, not a fixed decision.

$17,500

Saved per month on a $3M development

Move in sooner. Earn sooner.

Every month saved is rent paid, rent earned, or financing saved.

For homeowners, building faster means months less of paying rent. For investors, rental income starts sooner. For developers, every month saved on a $3M project at current financing rates saves approximately $17,500. The speed of CJG's system is not just a convenience. It is a financial argument.

50 yrs

Design lifespan — vs 25–35 standard

A structure that lasts

Steel does not rot. EPS does not degrade. Built for 50 years.

Steel frame and EPS composite panel is designed for 50 years and beyond. Steel does not rot, warp, shrink or attract pests. EPS insulation does not compress or degrade over time. The thermal performance you have on completion day is the thermal performance you have in 30 years. Your building is a long-term asset.

Certified

Fire rated and seismic rated for NZ

Fire rated. Seismic rated.

Structurally certified for New Zealand's requirements.

CJG's structural system meets New Zealand's seismic requirements and carries a fire rating that reflects the performance of the materials used. Steel does not burn and does not feed a fire. The peace of mind is not marketing. It is built into the structure from the first panel installed.

$90K

Average maintenance saving over 50 years

Minimal maintenance. For decades.

No repainting, no pest treatment, no moisture remediation.

Steel does not need treating. WPC does not need painting. EPS does not need remediation. The maintenance demands of a CJG home over 50 years are a fraction of what standard construction requires. Estimated saving: $60,000 to $120,000 over the life of the building. That stays in your pocket.

0 L

Water used in the construction process

Better for New Zealand

No water used. Minimal waste. Fewer movements. Less carbon.

The construction process uses no water. Panels are cut to exact specifications off-site so material waste on site is minimal. A faster build means fewer vehicle movements over fewer weeks. WPC interior cladding contains recycled materials. A better building that is also better for the country it stands in.

Bank

Managed escrow — your funds protected

Your money is protected

Escrow managed by your bank. Released only as milestones complete.

CJG operates an escrow payment structure managed by your bank. Your funds are held securely and released only when each milestone is completed and verified. You do not hand over money and hope for the best. Your risk is controlled at every stage of the project.

10 yrs

Guarantee — double the industry standard

Backed by 10 years

Double the industry standard. Because the materials justify it.

The standard NZ construction guarantee is one to two years on defects of workmanship. CJG offers 10 years. That is a reflection of confidence in the materials. Steel frame, EPS panel and WPC cladding do not fail in the ways that generate warranty claims. The 10-year guarantee is the logical consequence of building with a system that lasts.

Who we build for

One system.
Every project.

The same structural performance applied to every type of build. What changes is how we apply it.

Steel frame home built by CJG Auckland New Zealand residential construction

Homes · Granny flats · Rebuilds

For families, homeowners and investors

Whether you are building your first home, adding a granny flat for rental income or family, rebuilding on land you already own, or starting small with a plan to extend — CJG delivers a Healthy Homes compliant structure at a price that makes the decision straightforward.

New homes — single to multi-storey, designed from scratch for your site
Granny flats to 70m² — no resource consent required, built fast
Multi-generational homes — acoustic privacy for every generation
Expandable structures — start with what you need, extend when ready

Get a quote for your residential project

Commercial warehouse construction CJG New Zealand

Warehouses · Offices · Facilities

For businesses that need space that performs

CJG builds commercial facilities that work structurally, acoustically and operationally. Need a warehouse with a proper acoustic office environment inside? A standalone building for your business? A facility that adapts as the team grows?

Warehouses with integrated acoustic office environments
Office buildings — 2 to 4 storeys
Adaptable facilities — reconfigure as your business changes
Commercial builds for owner-occupiers and investors

Discuss your commercial project

Development land Auckland New Zealand land partners CJG

Your land · Our expertise

For landowners ready to do more

Your land is an asset. CJG explains every option honestly — sell, joint venture or develop — with no pressure and no commitment required. If you decide to build, we manage everything from first design to handover.

Honest feasibility conversation — understand your options first
Joint venture structures available
Single builds or multi-unit developments
Faster build means your asset returns sooner

Explore what your land could become

Residential apartment development CJG Auckland New Zealand developer partners

Better margins · Shorter cycles

For developers who run the numbers carefully

Up to 30% lower build cost and up to 50% faster delivery change the economics of every development. One construction partner, consistent quality across every unit, a fixed price and a process that does not surprise you mid-project.

Residential developments — townhouses, apartments, multi-unit
Fixed price turnkey — one contract, one team
No variations executed without your written approval
Shorter build cycle means less construction financing cost

Talk about your next development

Our process

From first conversation
to keys in hand.

Nine steps. One team. No surprises.

Initial consultation

We listen first. You tell us what you want to build, where, and what matters most. We give you an honest all-in cost estimate before the conversation ends. No base rates. No hidden extras discovered later.

Design and structural calculations

Our team designs your project from scratch based on your brief, your site and your preferences. Every design is bespoke. Structural engineering calculations completed in-house to NZ Building Code standard. Seismic and fire rated.

Quote approved. Contract signed.

You receive a full itemised quote. We walk through it together. Once you are satisfied, the contract is signed and your escrow account is opened with your bank. Your money is protected from this point forward.

Manufacturing and consent simultaneously

Most builders wait for consent before ordering materials. We do not. Manufacturing of your steel frame and EPS panels begins at the same time as the consent application is processed with your local council.

This is why CJG builds faster. Weeks saved on every project.

Shipment arrives on site

Your structural components arrive on site on schedule, cut to specification and ready to install. No waiting. No reordering. No delays caused by material management.

Construction and installation

Steel frame erected, EPS panels installed, WPC interior cladding fitted. Weathertight in weeks. Your building takes shape on a timeline you can see and rely on from day one.

Finishing

Kitchen, bathroom, flooring, electrical and plumbing completed to the specification agreed at contract stage. Standard or premium. Everything decided before work begins. Nothing changed without your written approval.

Handover

We hand you the keys to a completed, code-compliant, Healthy Homes certified building. Full handover documentation provided. Your 10-year CJG guarantee begins on this day.

After handover

CJG does not disappear after the keys are handed over. Your 10-year guarantee is active. Our team is reachable. If anything needs attention in the first decade, we are the people you call.

Built better.Priced fairly.

The system that makes sensefor New Zealand.

Every advantage.No trade-offs.

One system.Every project.

For families, homeowners and investors

For businesses that need space that performs

For landowners ready to do more

For developers who run the numbers carefully

From first conversationto keys in hand.

Tell us aboutyour project.

Built better.
Priced fairly.

The system that makes sense
for New Zealand.

Every advantage.
No trade-offs.

One system.
Every project.

From first conversation
to keys in hand.

Tell us about
your project.