The big construction sustainability win that is often overlooked

Projects championing new green building materials or lower-carbon construction methods dominate headlines and conference stages when the industry talks about sustainability.

Innovations like those are worth celebrating, but the reality is that the largest sustainability wins for construction right now aren't coming from what we build with; they're coming from how well we plan before we build at all.

Sustainability gains from better planning are harder to photograph – they happen before the first shovel even breaks the ground – but their potential to reduce waste and carbon emissions, and save time and money, eclipses almost any other single action.

Overseas research from the US Construction Industry Institute puts rework costs at around 5% of a project's value, with some studies placing it as high as 20%. In my 25 years in the industry, I've even seen other companies' projects sent back to the drawing board mid-construction – that's the kind of waste and delay no amount of clever materials selection can offset.

The fix to many re-work issues isn't complicated: better planning, and involving builders and subcontractors early enough that their experience shapes the design, not just the delivery. Working in silos rarely works. Collaboration does.

Documentation is one place this plays out directly. A late design change communicated informally, rather than through a proper drawing revision, can easily get lost by the time the next stage of work begins. At Hawkins, we tag every change directly to the shared digital models everyone on our projects works from, so nothing falls through the cracks between a sketch and a formal drawing update.

There's a whole lot of technology and systems making effective planning and collaboration far easier to achieve than in the past. Modern Building Information Modelling (BIM) platforms let multiple parties collaboratively plan, test engineering solutions and materials against a shared model, and sequence construction more efficiently – before a single dollar is committed to site.

Research published in the peer-reviewed Ain Shams Engineering Journal in 2025 modelled the impact of BIM-based design coordination on a sample construction project and found it led to a 15% reduction in embodied carbon, as well as 10% decrease in cost. That's a great reminder that sustainability gains and efficiency gains often go hand in hand.

At Hawkins, using Revizto collaboration software is business-as-usual across every project we run, from commercial towers to airports, universities and hospitals, and it's a meaningful part of why our rework costs are lower than some others.

It's a pity BIM and digital collaboration software isn't even more widely used across the sector. In a procurement environment that often rewards the lowest up-front price, the unfortunate truth is that digital collaboration tools can be the first thing cut to trim a tender. That's a false economy because it only shifts cost into the asset's operating life instead, through unforeseen issues during construction and, later, maintenance crews cutting exploratory holes in walls to find services that were never properly mapped.

The sustainability gains show up in many smaller ways too. Some of the projects we work on can generate as many as 12,000 A3 PDF drawings, constantly revised and required by 400–500 people at once. Managing that digitally rather than in print isn't just a massive paper saving – it also means field teams can navigate the current version of a drawing on site from an iPad or laptop, reducing construction errors that come from someone building off a superseded plan.

The numbers I'm seeing on the projects I work with are compelling. Since the start of June, Hawkins has had more than 300 unique users of our Revizto digital collaboration system, and more than 200 of them have been from external client companies or subcontractors who are all working together on the one platform. Between them, there have been 8,966 interactions within the platform – at a conservative five minutes saved per interaction, that's 747 hours saved, or roughly 249 hours a month. 

That kind of efficiency helps teams focus their time on the decisions and activities that most directly support successful project completion, while reducing delivery risk and the likelihood of time and cost overruns. 

Some companies, including ours, are extending BIM tools into 4D modelling – which incorporates construction sequencing, not just an asset's geometry – so different scenarios for resilience works can be gamed-out before construction starts. Used in this way, BIM isn't just a standalone piece of software, it is embedded as part of the design management approach. 

It's particularly helpful for some of the large projects we work on, which require as many as 80,000 individual seismic restraints to hold services and other non-structural building components in place so they survive an earthquake and don't pose a danger to occupants. Getting all those restraints right in a 4D model before work begins, rather than discovering a clash on site, avoids a mammoth amount of rework.

Of course, technology isn't the only way to generate sustainability gains that doesn't involve innovative material use or low-carbon construction methods. The shift towards design and build contracts, where a single consortium or alliance holds both design and construction expertise under one agreement will also help our industry in future. This is embedded in many government agreements in Australian states, including New South Wales and Queensland, and it's starting to emerge in New Zealand through Pre-Construction Services Agreements (PCSAs).

Too often, design is handed to a consultant with limited input from the contractors who will actually build the project, and rework follows when the design meets the realities of the site and supply chain. Under a genuine design and build two-stage managing contractor model, contractors can work with their own design team from the outset, agree a firm price once design is 70–80% complete, and largely remove the need for value engineering later.

As AI adds another layer to digital twins – from automated scheduling to compliance tracking – I expect models to move from reference tool to core contract document. That shift, so that contractors can price and build directly off the model rather than a 2D drawing, will be another genuinely valuable step forward for accountability and sustainability in the industry.