Biobased building materials in the Dutch Environmental Database

Importance of biobased construction

Biobased building materials can potentially make a significant contribution to the Dutch climate targets through the use of sustainably produced, renewable (inexhaustible) materials and through the positive effect of the biogenic carbon stored in biobased building materials. However, only a very small proportion of the materials used by the Dutch construction industry are currently biobased: approximately 2% is wood, while other bio-based materials only account for 0.1%.

The construction sector’s unfamiliarity with these materials and their environmental performance is a major barrier to their implementation at a larger scale. The inclusion of more biobased building materials in the Dutch National Environmental Database, which can be used to calculate the environmental performance of buildings, could help to ensure that these materials are used more often.

Biobased materials in the NMD

The NMD is a database that architects and project developers can use to assess the environmental performance of a building. Users of validated calculation tools can only calculate the effects of biobased materials if their product data are included in the NMD. Meanwhile, more and more clients in the civil engineering sector are including environmental performance as an award criterion in their tenders. A category 1 environmental declaration can therefore make the biobased products of building materials suppliers more competitive for the larger construction projects.

During the project, a total of 36 environmental declarations and 3 basis processes of 11 new biobased building materials have been included in the NMD. The TKI subsidy made it easier for participating companies to have a category 1 environmental declaration drawn up, in addition to existing fiscal support measures such as the MIA/VAMIL scheme.

A lifecycle analysis for biobased materials

Within this project, the environmental performance of a number of biobased building materials, such as wood, hemp, expanded cork and wool based products, has been mapped via life cycle analysis and entered into the NMD as a category 1 environmental declaration. In addition, the potential of these materials to store and retain biogenic carbon during long-term service life has been examined. By keeping these materials in use for a long time of time –for example through a longer service life, reuse and recycling – they can make a significant contribution to the climate targets. Project results also show that, partly due to the increasing attention for sustainability and circularity, the share of wood from the demolition of buildings that is currently reused or recycled is much higher than previously assumed. The research results have been published (see bottom of this page), with the recommendation that the insights obtained should be incorporated as much as possible into the NMD’s LCA methods.

Environmental benefits of biobased building materials

The environmental benefits of biobased building materials are often stated qualitatively. In this project, a quantitative comparison with conventional building materials has been made based on reference buildings and using the NMD Determination Method. This shows that the environmental impact of biobased building is clearly lower than that of conventional building methods.