Full-scale Demonstration: Comparing Conventional and Innovative Building Materials for a Low-Carbon Future

As part of the INBUILT project, two full-scale demonstration modules are currently under construction at the facilities of Leipfinger-Bader, an innovative brick and building materials manufacturer, in Pfeffenhausen, Germany. The demonstration site is designed to make sustainable construction practices visible, proving that low-carbon materials and circular design principles are not only technically feasible, but ready for immediate application.

In this context, two twin buildings, the Reference Module and Office Plus Module, are being developed to directly compare conventional construction materials with the innovative, low-carbon solutions produced within the INBUILT project. The results will generate robust and practice-oriented evidence for industry, research and policymakers. This initiative represents a key step towards Technology Readiness Level 7 validation, translating innovative products into standard construction practice and assessing their potential for industrial uptake.

Twin Demonstrators for a Direct Comparison

Built according to circular and low-waste construction principles, both buildings share identical geometry and layout, a compact single-storey unit of 9.73 × 3.77 m with two rooms, including a bathroom (4.68 m²) and a working/living area (21.26 m²). In particular, the structures are built on strip foundations and follow the same design principles, ensuring that conventional and the innovative configurations can be compared directly.

While the Reference Module is built using standard materials, the Office Plus module integrates a range of INBUILT innovations, such as:

• Fired wall bricks with a high proportion of recycled and reused material and filled with bio-based insulation – used for the exterior wall (Leipfinger-Bader), offering reduced embodied carbon and improved thermal performance;
• Hybrid straw–clay interior boards with innovative clay-based render – used for the interior lining (Leipfinger-Bader), providing natural humidity regulation and a fully bio-based alternative;
• Insulation mats made from recycled wastepaper – used for the ceiling insulation (Balticfloc), offering a low-carbon, recyclable solution with high thermal efficiency
• Non-fired bricks with a high proportion of recycled and reused material – used for the partition wall between bathroom and living/office area (Leipfinger-Bader), significantly reducing energy use in production and allowing full material recyclability;
• Second-life photovoltaic panels for supplementary power generation – installed as additional energy supply system (CEA), extending the lifespan of existing PV technology and reducing electronic waste.

In addition, complementary materials from the EASI ZERo project, including an exterior insulation render (Sievert) and a bio-based polyurethane (Bio-PUR, Indresmat) system for window blind box insulation, highlight the strong cross-project collaboration within the European research landscape.

Monitoring Under Real Conditions

Construction of both modules is already underway, with completion planned for the end of January 2026. Following the construction phase, the buildings will undergo a one-year monitoring campaign covering all seasons.

The University of Stuttgart, one of the partners of the INBUILT project, is responsible for installing and operating a comprehensive sensor network to continuously monitor temperature, humidity, material moisture, and energy consumption, complemented by outdoor weather data. This integrated setup makes it possible to thoroughly assess how conventional and circular construction approaches perform under identical real-world conditions, particularly with respect to energy efficiency, thermal comfort, and material durability.

Towards Quantifiable CO₂ Reduction

The demonstration aims to provide measurable data on the environmental and functional benefits of INBUILT products. By replacing conventional mineral and synthetic materials with bio-based, recycled and reused components, the Office Plus module is expected to significantly reduce embodied carbon and improve resource efficiency while maintaining high levels of thermal and structural performance. Together, these innovations are anticipated to lower embodied carbon by roughly 60 % compared to their traditional counterparts, contributing to more climate-neutral buildings.

The results gained from the demonstrator will help validate the project’s approach of integrating circular design principles into standard construction practices. They will also provide valuable feedback for future industrial applications and market adoption, supporting the transition to climate-neutral construction.

After the completion of the INBUILT project, the two modules will be relocated from Pfeffenhausen to Vatersdorf, both Leipfinger-Bader sites, where they will continue to serve as office buildings. This long-term use ensures that the demonstrators remain active and functional spaces rather than temporary test structures, offering a lasting example of how innovation can be integrated into everyday building practices.

A Showcase for European Collaboration

The demonstration at Leipfinger-Bader embodies the spirit of INBUILT: bridging innovation and application, uniting industrial and research expertise, and proving that circular construction is not only possible but practical. It also acts as a visible example for education and knowledge exchange, inspiring professionals, students, and the wider public to rethink the future of sustainable construction. Through this initiative, the consortium takes an important step towards a more responsible, low-carbon, and circular future in the European built environment. These buildings symbolise what joint forces can achieve when innovation in construction techniques meets responsibility, showing that the future of construction is not a distant vision, but something we can build today.

This article was written by Fabian Teubl (HeiQ) and curated by Giorgio Alessandro (Greenovate! Europe) for the INBUILT project.