By Thomas Møller Christensen, AAU Communication and Public Affairs
Photo: Astrid Maria Rasmussen

"When we look at how timber construction affects the climate, it is important to connect the life cycle assessments we use to the specific decisions made."

This is explained by PhD candidate Rasmus Nøddegaard Hansen from BUILD -Department of the Built Environment at Aalborg University. In his Ph.D. dissertation, he investigates the environmental sustainability of timber construction and emphasizes the need for a more nuanced approach to assessing their climate impacts.

"You cannot unequivocally say that timber is always better. Among other things, it depends on how architects and engineers can integrate it into building design and construction," he states.

Several factors at play in climate assessments

Rasmus Nøddegaard Hansen encourages a re-evaluation of the traditional perception of the unequivocal climate benefits of timber construction by pointing out improvement potentials in the system models used in life cycle assessments (LCA). LCA is an important tool for assessing how construction affects the climate, but it can be oversimplified when it comes to timber construction.

For instance, the by-products from timber materials are not taken into account in the current LCA system models, even though they can constitute a significant part of timber construction's impact on the climate, he explains:

"When you use round timber for material production, about half can end up as primary construction material in timber. Parts of the remaining products can be used for particleboard, while the rest replaces other production on the market such as cardboard packaging or energy. This exchange in the market can have a significant impact on the climate and environmental impact of timber products." He continues:

"Furthermore, there is a challenge in the LCA system models when looking at how increased market demand for timber affects the world around us. With an increase in demand comes greater pressure on our already limited areas. It is important that we improve our knowledge so we can analyze and manage this pressure on areas," he explains, highlighting fast-growing bio-based materials as a future part of the solution to the challenge.

Need to include more aspects in the analyses

Rasmus Nøddegaard Hansen explains that the construction industry can achieve a better understanding of the environmental impact of timber construction and thus find more sustainable solutions for construction projects by addressing the shortcomings in LCA system models.

"It is not just about spotting the problems, but also about solving them. We should aim for an approach that covers everything from material selection to production methods, with a focus on a broad range of environmental impact categories and the economic consequences of new construction methods in the market," he concludes and adds:

"In addition, we should work on minimizing material usage in general. This will drive sustainable development in the construction industry."

Rasmus Nøddegaard Hansen will defend his PhD dissertation on May 14 at BUILD in Copenhagen.