While modern buildings may operate more sustainably than existing ones, these climate gains are incremental. One study looked at new builds that were 30% more sustainable than average existing buildings. It showed the new builds would take 10 to 80 years to make up for the negative climate change impacts of the construction process.

Given that the New Zealand building and construction sector accounts for around 20% of our greenhouse gas emissions, it’s true that the greenest building is the one that’s already built.

The sustainability credentials are undeniable, but adapting existing structures always comes with unique constraints, which add time, complexity and cost:

• Buildings that predate modern standards of health and safety can be expensive to bring up to code. Under the Building Act 2004, for example, changing a building’s function usually means it must meet all current code standards for strength, insulation, accessibility and fire safety.
• Loose wording in the Act also leaves room for interpretation of how far the upgrades need to go, which makes getting consents more complex.
• Older buildings may come with hazardous materials, outdated plumbing or wiring, and the risk of unexpected issues. These factors can make it more difficult to secure funding.
• Coordinating architects, engineers, heritage consultants and local authorities can make managing a reuse project more complex and higher risk.

Even so, the benefits of adaptive reuse projects can go beyond sustainability returns. For simpler projects, studies show reusing existing buildings shortens construction projects and saves money – one study puts those savings at 10-12% on a new build. By retaining the character of the original structure, reuse can also result in a higher-value property.

The difference between an adaptive use project that delivers those benefits and one that costs more than it returns often comes down to your construction partner. Adaptive use projects rarely fit neatly into cookie-cutter project management frameworks, so will need a flexible, strategic and creative approach.

Bring in the experts early

Adaptive reuse projects are often about expecting the unexpected – concealed services, ageing materials or hidden damage. You can manage those risks and ‘what ifs?’ when you know about them – bring in your architects and engineers before you buy a property or launch your project.

Insist on unified workflows, not siloed stages

Adding modern functionality to older buildings isn’t an easy design project – it’s one that takes both creativity and technical fluency. An integrated delivery model is essential, bringing strategy, design and construction into one workflow. That means feasibility, buildability, cost and cultural considerations can evolve together, not one after the others.

To do that, align your heritage specialists, engineers, designers, regulatory advisors and construction teams on the project’s intent, constraints and success measures. This keeps design grounded in technical and regulatory reality. It’s also the best way to surface potential risks before they become expensive issues.

Consider Space Users

Unlike new builds, many adaptive use projects must also consider those working and living in the existing space, and who will be the structure’s users down the track. Understanding how people actually use a building helps shape smarter design decisions and smooths delivery. Early engagement also earns user buy-in, reducing disruption and resistance to change.

Seek strategic hybridisation

The best adaptive reuse projects are ones where design and construction teams think strategically about what’s worth keeping and where a rebuild will optimise performance, compliance or cost. That requires a construction partner who works closely with – or owns – the design process and takes time to understand your business. They need to know how the space will function, what matters most operationally, and where flexibility will be needed in future.

Case study: WSP, Auckland 

Faced with a tired workspace, WSP in Auckland set out to modernise rather than replace its offices. Expedite applied a value allocation tool to identify what could be repurposed, keeping waste and costs down, while preserving as much embodied carbon from the original space. Expedite delivered the construction during a rapid eight-week programme while the office was empty over the summer break, finishing up seven days ahead of schedule.

Case study: Lichfield Towers at Selwyn village

More than 60 years old and part of one of Auckland’s earliest retirement facilities, Lichfield Towers needed significant renewal: more natural light and modern amenities, without losing its mid-century character or disrupting its 80 residents. Expedite’s solution was a storey-by-storey construction sequence, which meant residents only had to relocate for a few weeks at a time. This phased approach reduced disruption, maintained access for visitors, and saved Selwyn significant rehousing costs. The project was completed 20 days ahead of schedule.

It’s easy to conflate sustainable construction with new low-carbon materials or energy-saving technology. The climate gains these deliver are tiny compared to the act of simply building less. Retaining existing structures means preserving embodied carbon and reducing waste. That can also come with the added benefits of saving time, money and heritage features.

Managing outdated infrastructure, hidden issues and regulatory complexity takes strategy and thought, but with the right partner, the rewards can be well worth the effort.