The companies Södra and Peab are working together to develop a sustainable hybrid frame solution

One of Europe's largest forest industry companies, Södra, wants to create a new generation of environmentally friendly timber frame by combining cross-laminated timber (CLT) and reinforced concrete structures. The Swedish company announced recently in March that it would be working with one of the region's largest builders, Peab, to develop this hybrid solution further.

“Through this collaboration we want to explore how to develop hybrid frame solutions that could be delivered on a larger scale, based on parameters of economy, functionality and sustainability,” says Andreas Berge, head of the Södra business area responsible for Södra Building Systems. “It is about overall optimisation, using the right material in the right place.”

“By combining the low climate impact and light construction of timber with the strength, stability and weight of concrete, we get the best of both ‘worlds’,” explains Carl Rölcker, acting managing director of Peabbolaget Byggelement. “We see potential in a solution based not on ‘either/or’ but on collaboration. With this initiative we are taking a step further towards more sustainable construction, without losing functionality, an economical approach or new building opportunities.”

The collaboration will focus on developing a standardised ECO hybrid frame solution for prefabricated construction. It follows the announcement in 2024 that Metsa Wood was combining cross-laminated timber and reinforced concrete to build so-called sandwich walls.

Research – hybrid timber systems could become the “new reinforced concrete”

The new partnership is being formed at a time when hybrid systems of timber, concrete and steel are being studied in order to meet climate commitments.

In March 2022 researchers at the Fraunhofer wood research institute Wilhelm-Klauditz-Institut** began a research project to examine the long-term value of using timber and concrete in hybrid building systems.

Scientists around the world are studying the combination of timber and concrete, as well as the use of timber reinforced with carbon fibres or flax fibres in polymer matrices to increase its stiffness. Researchers have developed a new system for joining timber and concrete without using nails, plates or grids.

Professor Libo Yan, the project's lead scientist and head of the research group, explains: “By joining the materials with polyurethane or epoxy resin, we can reduce the weight of the timber hybrids and speed up the production process by as much as 15%.”

* Peab has been operating in the Swedish construction industry for sixty years. The company's beginnings date back to 1959, when it was founded by the brothers Mats and Erik Paulsson. Today Peab is Sweden's largest and the Nordic region's leading construction and civil engineering company.

Houses, schools, kindergartens, homes for older people, museums, shopping centres, offices, cultural and sports arenas, libraries, town halls, roads, bridges, parks – all built thanks to Peab. “The company is what it is today only thanks to our staff. Talented and determined people have always been at the heart of Peab's success,” stresses Peab's chief executive Jesper Göransson.

“With our focus on active collaboration, we created a family feeling in the company. Preserving it has always been the main goal as our company has grown. It is the basis of good workplaces, satisfied customers and excellent profitability,” says the company's founder, Mats Paulsson.

** Sustainability has been the central theme at the Fraunhofer Wilhelm Klauditz Institut since its founding in 1946. The institute's founder and namesake, Dr Wilhelm Klauditz, sought ways to make optimal use of untreated timber – a raw material that had become scarce as a result of the war – and to find technical uses for timber residues and small-dimension timber. Klauditz is regarded as the pioneer of the modern wood-based materials industry. Today the Fraunhofer WKI uses the full range of renewable raw materials to develop sustainable materials, components and chemical products. Particular attention is also paid to the sustainable use of plant residues and production waste.