Abstract

The construction sector faces escalating pressure to reduce embodied greenhouse gas emissions while transitioning from linear material use toward circular, regenerative systems. Biobased modular wall assemblies designed for disassembly and reuse are increasingly promoted as a pathway to address both challenges; however, robust empirical comparisons with conventional construction remain limited, particularly when assessed across different life cycle assessment (LCA) methods and circularity assumptions. This paper presents a comparative, multi tool, and multi cycle LCA of prefabricated biobased modular wall systems developed within two EU research and demonstration projects (Drive 0 and Circ Reno), benchmarked against conventional external wall insulation systems in retrofit contexts and masonry cavity wall construction in new build scenarios. Environmental performance was assessed using ICE database screening, Ubakus elemental LCA, and OneClick LCA whole building modelling, applying harmonised functional units but varying system boundaries and datasets in order to explicitly examine methodological sensitivity. Both single life (100:0) and multi cycle allocation scenarios (Linear Degressive and Circular Economy Linear Degressive) were explored to evaluate how design for disassembly and reuse potential are represented within current LCA frameworks. Results show that, under single life cycle assessment, modular systems may exhibit higher mass and embodied impacts than lightweight bonded solutions, particularly where additional framing, fixings, and protective layers are required. However, increasing levels of biobased material integration substantially reduces embodied carbon intensity, and results are highly sensitive to database choice, system boundaries, and biogenic carbon accounting conventions. When multi cycle reuse scenarios are applied, modular systems designed for disassembly demonstrate 21–45% reductions in cumulative embodied GWP relative to conventional systems, depending on the allocation method adopted. In a high biobased new build prototype incorporating straw based insulation and timber construction, embodied carbon was reduced by 72% per m² compared with an equivalent performance masonry cavity wall, while meeting passive level thermal targets. The study demonstrates that circular and biobased construction outcomes cannot be meaningfully interpreted through single life, linear LCAs alone. At the same time, it highlights significant uncertainties related to dataset maturity, proxy environmental product declarations, future reuse assumptions, and allocation choices. Rather than presenting definitive performance rankings, the paper positions these results as conditional insights, illustrating how methodological decisions shape the visibility—and potential undervaluation—of circular design strategies within current LCA practice. The findings underscore the need for improved data availability for biobased materials, transparent alignment of allocation methods with decision making contexts, and policy frameworks capable of recognising multi cycle building systems as temporary material infrastructures rather than disposable products.

Keywords

Architectural Technology, Biobased Materials, Circularity Performance, Design for Disassembly, Environmental Design, Life Cycle Assessment, Modular Systems, Sustainable Building

Publication Date

2026-03-10

Publication Title

International Journal of Architectural Engineering Technology

Volume

13

Issue

1

First Page

116

Last Page

136

Deposit Date

2026-10-30

Funding

This research draws in part upon research undertaken with two EU funded research projects, Drive 0 EU Horizon 2020 project Grant No 841850 and Circular Renovation (Circ Reno) EU InterregNW project funding Grant No NWE0100144

Creative Commons License

Creative Commons Attribution-NonCommercial 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

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