Reuse of construction materials

Reuse of construction materials is rewarded in the Nordic building LCA

Publiceret 09-05-2023

The Nordic countries face similar challenges when it comes to incite reuse in construction.
One way forward is through Life cycle assessment (LCA) of buildings where reuse of construction material is rewarded in the climate declarations for buildings. Currently, there is a window of opportunity for harmonising the approaches on to how to calculate reuse in LCA for buildings.

All of the Nordic countries have a strong focus on minimising the climate and environmental impact from construction. One method to do so is by implementing regulation that contribute to the decarbonisation of the building stock, such as obligatory climate declarations and setting a limit to how much CO2 you can emit when building.

Reuse of construction materials as the attractive choice

A major part of the climate impact of new buildings happens in the building phase because a lot of materials, often virgin resources, go into the production and it requires large amounts of energy to produce and transport construction materials. This makes reuse of construction materials an attractive choice when building; especially for countries like Denmark who have introduced limit values for the carbon footprint of buildings in the Danish building code. However, the question is: how should the emissions from reused construction products be calculated in LCA for construction?

Window of opportunity for more aligned methods of calculating emissions from reused construction products

Sweden, Finland and Norway have already chosen to give reused construction products an advantage by setting the CO2-emission to zero for the modules A1-A3 (raw materials, transport and manufacturing) in the LCA calculations. Norway differs slightly as they include the CO2-emissions from the processing of the product as well.

In a new political agreement, Denmark has also chosen to set the CO2-emissions for reused construction products for the LCA modules A1-A3 to zero, hence the same as the other Nordic countries who have made regulation on this.

The Danish broad political agreement is currently in National hearing and the principles are expected to enter into force on January 1st 2024. Iceland is currently working on a roadmap for decarbonisation, and it is expected that more details on their regulation in this field will come later this year.

These are all important first steps; there is, however, still an open window for more harmonised approaches for the other modules of the LCA: The Nordic countries still use different methods, and they do not include the same LCA modules.

As an example, Sweden, Finland and Norway have chosen to include module A4/A5 (transport to site and installation) in their national climate declarations and thus have an aligned calculation approach.
The modules A4/A5 relates to the emissions from the transportation to the building site and the construction process, and for all three countries counts, that you can either include the generic values from a national database or calculate exact emissions. In Denmark, this phase is not yet included in the LCA and therefore, it is also not yet defined how a reused product should be calculated.

In the table underneath you can get the full overview of the LCA modules, which are relevant for reused products and how they are calculated - or expected to be calculated - in the modules across the Nordic countries.

How the Nordic countries calculate CO2-emissions from reused products in the LCA of new buildings

This table illustrates resemblances and differences in how the Nordic countries calculate CO2-emissions from reused products in the Life Cycle Assessment of buildings.