Bio-based materials and engineered timber construction

Embodied emissions, which result from producing and transporting construction materials and waste, as well as assembly, disassembly and disposal, are responsible for between 5 and 12% of EU Member States’ total emissions.

Concrete and steel, two of the most important construction materials, have large embodied emissions, which are hard to reduce due to their chemistry and manufacturing processes. Bio-based materials – those from nature – have the potential to be more sustainable.

What the JRC is doing

The JRC is developing novel methods to apply bio-based materials and engineered timber in construction and renovation.

Its NOTICE-EUB project (NOvel TImber Composites for Energy and Seismic Upgrading of Buildings) has evaluated the use of prefabricated cross-laminated timber (CLT) panels in building renovation, demonstrating seismic safety through full-scale experiments.

The JRC’s Novel Modular and Reusable Panels for Safe and Carbon-free Buildings (REUSE) project explored the potential of CLT panels in modular construction.

Prefabricated timber panels for building renovation

The EU-funded NOTICE-EUB project provides a sustainable solution for reducing seismic risks and improving energy efficiency in European buildings.

Hosted by the JRC Ispra, the project introduces an innovative timber-based retrofit system designed to enhance seismic resilience and energy efficiency with minimal environmental impact.

NOTICE-EUB is funded through Horizon 2020 – Marie Skłodowska-Curie Actions.

Advantages

The CLT-based renovation system has wide applicability as it was designed for reinforced building types in Europe’s residential stock.
Reversibility, low invasiveness and lightweight nature of the method allow it to be adapted for other, more sensitive structural systems, such as unreinforced masonry buildings.
Speed and ease of assembly, minimising downtime and labour costs.
Innovative approach which prioritises damage control, localising repairs to low-cost and easily replaceable metallic connectors, preventing dangerous collapse mechanisms often associated with traditional brick-masonry infill walls.
Significant improvements in structural safety against earthquakes, meeting modern performance-based seismic design standards.

Experimental testing

Proposed timber-based seismic retrofit system.© European Commission

Full-scale testing has been carried out at the JRC European Laboratory for Structural Assessment (ELSA) and the University of Trento, demonstrating promising seismic and thermal performance.

Advanced hybrid earthquake tests have been coupled with blower door tests, assessing how the CLT-based retrofit system moderates air infiltration, ensuring the functionality and effectiveness of the integrated thermal insulation system across a sequence of simulated seismic events.

Detailed retrofit design guidelines, derived from experimental and numerical research, will soon be available, offering valuable insights for engineers, policymakers and stakeholders. This transformative project is poised to influence the future of building retrofits across Europe.

The experimental evidence generated by these projects also supports the JRC’s role in developing the structural Eurocodes, whose second generation expands the design provisions for timber structures, including CLT and the seismic design of timber buildings.

Supporting EU policy

By integrating thermal insulation materials into the design, the proposed retrofit system not only strengthens buildings but also delivers significant energy savings, aligning with the revised Energy Performance of Buildings Directive (EPBD), which emphasises energy-efficient renovations alongside structural improvements.

This dual-purpose approach supports the goals of the European Green Deal, the Renovation Wave and New European Bauhaus initiatives, promoting safer and more sustainable building stocks across the EU. The use of bio-based materials also addresses embodied emissions, which the revised EPBD brings into focus by requiring the life-cycle global warming potential of new buildings to be calculated and disclosed.

The timber-based retrofit system integrates mineral wool panels for thermal insulation.
© European Commission

Smiroldo F, Kallioras S, Sommacal G., Bournas D.A., Piazza M, Giongo I., 2023. Full-scale testing of masonry-infilled RC frames retrofitted with cross-laminated timber panels. Eng. Struct., 294, p. 116789, https://doi.org/10.1016/j.engstruct.2023.116789

Kallioras S, Pohoryles DA, Bournas D.A., Molina F, Pegon P. 2023. Seismic performance of a full-scale five-story masonry-infilled RC building subjected to substructured pseudodynamic tests. Earthquake Engng Struct Dyn.; 52:3649–3678. https://doi.org/10.1002/eqe.3940

Smiroldo F, Sommacal G, Kallioras, S, Bournas D, Piazza M, Giongo I., 2023. Material characterisation for the numerical modelling of a timber-based seismic retrofit for RC buildings. Procedia Structural Integrity, 44, 1893–1900. https://doi.org/10.1016/j.prostr.2023.01.242

Kallioras S, Bournas D, Smiroldo F, Giongo I, Piazza M, Molina FJ. 2024. Cross-laminated timber for seismic retrofitting of RC buildings: Substructured pseudodynamic tests on a full-scale prototype. Earthquake Engineering & Structural Dynamics. https://doi.org/10.1002/eqe.4222

Novel timber composites for energy and seismic upgrading of buildings

New European Bauhaus: beautiful, sustainable, together

Renovation wave