Mini CO2 Housing Digital Project

How can construction processes be rethought to minimize resource consumption and CO2 emissions?

With the MiniCO2 Apartment Building DIGITAL, Realdania By & Byg, together with a team consisting of Vilhelm Lauritzen Architects, Søren Jensen Consulting Engineers, HD LAB, and MT Højgaard Denmark, highlights how digital collaboration models can reduce time consumption, errors, and material waste.

10%. That is the average amount of material wasted during a construction project.

Misdeliveries, incorrect installations, and buildings handed over with defects and deficiencies are everyday occurrences in the construction sector, accepted for generations. Most construction projects allocate 10% of the budget for unforeseen events, a figure that is often exceeded.

The potential to streamline construction processes is immense. The construction sector accounts for 40% of Denmark’s economy, employs hundreds of thousands of people, and generates billions in revenue annually.

If material waste could be reduced from 10% to nearly 0%, it would be possible to construct 11 houses with the same resources typically used for 10 houses. The value of each house could increase by 10%. In other words, one could build 1.1 houses with the same time and resource consumption normally required for 1.0 houses.

Reducing Resource Consumption

With the MiniCO2 Apartment Building DIGITAL, Realdania By & Byg and the team aim to explore how digital tools can enhance collaboration and reduce resource consumption in terms of materials, costs, and time.

The house is a standard new residential building constructed from concrete and clad with brick, comparable to typical residential developments seen in Kanalbyen.

The hypothesis is that through meticulous planning and addressing the complexity of a construction project early, it becomes possible to build more accurately, with fewer errors both during the process and upon final delivery. The approach relies on a carefully planned process and close collaboration among all involved, supported by a precisely structured digital production framework developed collaboratively in a process led by the client.

An essential aspect of this approach is the ability to shift many detailed decisions to the early planning phases instead of making them "at the last moment," often involving stakeholders who were not part of the initial process.

The house was constructed in 2023 and handed over in December 2023 without defects and two months ahead of schedule.

Results

• Construction time: Approximately 10 months, about 2 months faster than expected.
• Budget savings: Built 8% under budget, with very limited additional work after contract signing.
• Flawless delivery: The house was handed over without defects.
• CO2 savings: A reduction in emissions during the construction phase (A4 + A5) equivalent to a 12% reduction in the project's overall life-cycle assessment (LCA), when material waste and transport are included, compared to the benchmarks of the Voluntary Sustainability Class (FBK). In terms of CO2, this equates to 0.9 kg CO2-eq/m²/year (compared to 2.4 kg CO2 in standard calculations)—a saving of approximately 60% in A4 and A5 specifically.