Faster, Greener, Cheaper: QIA’s Case Study on Modern Construction
Background – Building Smarter with Prefabrication
Quantum Insights Advisory (QIA) recently partnered with Green Timber Technology (GTT) to analyse a new construction approach for a residential project in Muswellbrook, NSW. The project – a dual-occupancy 2-bedroom, 2-bathroom duplex – served as a test case for GTT’s Modern Methods of Construction (MMC). GTT’s MMC approach uses prefabricated wall and roof panels built off-site in a factory and then assembled on-site. QIA was engaged to independently quantify how this prefabricated method compares to traditional building methods in terms of embodied carbon emissions, construction time, and cost. This analysis supported GTT’s application for a government grant promoting innovative low-carbon construction.
Embodied Carbon refers to the CO₂ emissions associated with producing and transporting building materials and the construction process itself (measured as “CO₂e”). This is a growing focus area for sustainability – in Australia, building material production and construction account for roughly 7% of total carbon emissions. Reducing this footprint is crucial for the property and infrastructure sector’s climate goals.
Comparing MMC to Traditional Methods
QIA’s study compared three scenarios for constructing the duplex’s shell (from the concrete slab up to the completed external walls and roof):
GTT’s Prefabricated MMC Panels – Factory-built engineered timber panels and roof cassettes, assembled on-site.
Traditional Timber Construction – Conventional on-site timber frame walls and timber truss roof.
Traditional Masonry Construction – Double-brick masonry walls with a timber truss roof built on-site.
The findings were striking. Using the same building design, the prefabricated MMC approach outperformed traditional methods on all key metrics – carbon, time, and cost.
Carbon: The MMC system resulted in 12.7 tonnes CO₂e, about 22% lower than the 16.3 tonnes for an equivalent all-timber build, and 68% lower than the nearly 39.8 tonnes for a masonry build. That’s a reduction of 3.6 t CO₂e versus timber and over 27 t CO₂e versus brick – a huge cut in embodied emissions. These savings come largely from using engineered timber (which has a lower manufacturing footprint than brick or concrete) and needing far less on-site energy (fewer days of generators and machinery) due to the rapid installation. A breakdown of emissions shows the biggest differences in materials (masonry production is very carbon-intensive) and on-site fuel usage. In practical terms, the prefab approach trimmed roughly a quarter of the carbon compared to building the same design with traditional timber, highlighting its potential for greener construction.
Time: Assembly of the factory-made panels was incredibly quick – only about 2.4 days on-site with a four-person crew to erect all walls and roofs for the duplex. In contrast, traditional methods would require 6–7 weeks of on-site work (40–51 days) to reach the same stage. That is roughly a 17-fold faster shell construction. In labor terms, the prefab method used just 74 on-site labour hours in total, versus well over 1,200 hours for the others. This dramatic time saving means the homes can be occupied or sold much sooner, reducing site overhead costs (supervision, equipment hire) and neighbourhood disruption. It’s also noteworthy that time savings directly translate to carbon savings – every week of avoided construction is a week of avoided fuel use for machinery and worker travel. As the report observes, the shorter on-site period for MMC inherently cuts down auxiliary emissions like generator fuel burn and daily commutes.
Cost: Despite the advanced techniques, the prefab method was slightly cheaper than the traditional alternatives in this case. On a per-square-metre basis, MMC cost roughly $307/m², versus $310/m² (timber) and $322/m² (masonry). Essentially, GTT’s method delivered a greener, faster build without a cost premium – in fact, with a small cost saving. The efficiencies of factory production (bulk material purchasing, reduced waste, faster cycle times) help keep unit costs competitive. While the cost differences here are modest (within a few percent), it dispels the notion that sustainable construction “must cost more.” And in a larger project, the indirect savings from shorter project duration (financing costs, earlier revenue, reduced preliminaries) can be substantial.
Why the MMC Approach Excels
Several factors inherent to GTT’s off-site construction approach drive these benefits:
Efficient Manufacturing: GTT’s wall and roof panels are produced in a controlled factory environment. Materials (timber, insulation, cladding, etc.) arrive in bulk and are assembled with optimized processes, resulting in minimal off-cuts. Any surplus can be recycled more easily than on a chaotic construction site. The case study used standard emissions factors (from NABERS data) to calculate factory impacts, and the results show that production efficiency kept the prefab carbon footprint low. Building in a factory also avoids weather delays and improves quality control, which can prevent costly rework. GTT was able to verify high labor productivity in the factory, which QIA had previously helped model for GTT’s costing purposes.
Lightweight Low-Carbon Materials: The MMC design uses timber-based components (engineered wood panels) instead of heavy masonry and concrete. Timber not only has lower embodied carbon per kg, it also stores carbon. In the study, the masonry option had to account for emissions from cement production, brick firing, and lots of on-site mortar mixing – hence its CO₂e footprint was roughly triple the prefab option. By using engineered wood and efficient transport, the MMC approach slashed those emissions. Also, less on-site power was required (fewer days running cranes, generators), further cutting carbon. The report notes that transport of prefab elements (Orange to Muswellbrook, ~300 km) was factored in at 0.00022 kgCO₂e per kg per km– and even with delivery, the MMC method was far greener overall.
Rapid On-Site Assembly: When the pre-made panels arrived at the site, the structure was assembled in just a couple of days using a small crew and a mobile crane. In about 2 days, the duplex was fully erected and weather-tight. Faster assembly means significantly reduced site preliminaries (shorter equipment hire, site management, and welfare provisions) which helped keep costs down. It also means less disturbance for the community and earlier start for follow-on trades (plumbers, electricians, etc.). The QIA analysis highlighted that the time savings from MMC directly reduce on-site energy use – for example, diesel for machinery and daily vehicle trips were much lower than in a 7-week build. In short, building faster not only saves money but also shrinks the carbon footprint by curtailing the energy expended on-site.
Quality and Safety Benefits: Although not quantified in dollars in this study, factory-built components often have superior quality (precise fitting, better sealing) which can improve building performance (energy efficiency, durability). Fewer days on-site also mean reduced safety risk for workers. These factors can lead to fewer delays and change orders, indirectly benefiting schedule and cost. GTT’s panels, for instance, came with services pre-routed and external cladding in place, reducing tasks needed at height on-site. The smooth execution observed in Muswellbrook hints at potential risk reduction – the project can be delivered on time and budget with fewer uncertainties, an attractive proposition for developers and financiers.
QIA’s Role – Independent Analysis for Validation
For this project, QIA provided the independent analysis and reporting that quantified these benefits. The scope included detailed cost estimating (leveraging data from sources like Rawlinsons and GTT’s supply chain info) and carbon accounting (using NABERS emission factors and Infrastructure NSW guidance for transport). By translating GTT’s innovative construction method into hard numbers, QIA helped demonstrate its value to stakeholders in an objective way. GTT used these findings in their government grant application, making a strong case that their approach aligns with public goals for cost-efficient, low-carbon construction.
From a broader perspective, QIA’s study serves as proof-of-concept that can be shared via the company’s website and LinkedIn. The accessible tone and clear data in the report help communicate the outcomes beyond technical circles, reaching property and infrastructure professionals who might be considering similar approaches. QIA’s unbiased analysis lends credibility to GTT’s claims, and it showcases QIA’s expertise in modern construction costing and carbon assessment.
Conclusion – A Blueprint for Sustainable Construction
This case study compellingly illustrates that modern construction methods can deliver tangible benefits for both builders and the environment. By partnering with GTT on the Muswellbrook duplex, QIA showed it’s possible to cut roughly a quarter of the embodied carbon of a typical low-rise build by using prefabricated timber panels instead of traditional methods. Equally impressively, this was achieved while slightly reducing costs and completing the structure in a fraction of the time of a conventional build.
Such results carry big implications. Faster project delivery means quicker return on investment and less time financing construction. Lower carbon footprint helps meet ESG targets and could future-proof assets against carbon regulations. With governments and industry pushing for net-zero construction, the ability to quantitatively prove carbon savings (as QIA did) is invaluable. GTT’s innovative kit-of-parts approach, backed by hard data, is a prime example of how the construction sector can evolve to meet 21st-century demands.
Key Takeaways for the Industry: Modern prefabrication techniques are not just theoretical – they are being used on real projects right now, and they can outperform traditional methods on multiple fronts. It’s crucial to evaluate new methods holistically; as seen here, considering carbon alongside cost and time reveals the full value. The Muswellbrook project shows that you don’t have to sacrifice financial feasibility to build green. In fact, you can have it all: a build that’s faster, cheaper, and better for the planet. QIA is proud to have helped quantify these benefits for GTT, and we look forward to supporting more projects that reshape construction for a sustainable future.
