Scaling Renewable Building Materials: Opportunities and Challenges

Renewable bio-based building materials can drive reductions in atmospheric carbon.

If managed responsibly, renewable bio-based building materials have a unique capacity to drive reductions in atmospheric carbon by: 1) matching renewable resources to building material applications, at lower carbon footprints, and 2) serving as a global carbon sink (see Figure 4.1). Timber is the leading bio-based building material being used at scale. Although promising technological product innovations are available to address rising demand for timber in developed countries, demand outpaces forest regrowth and relies on a limited range of tree species (Pomponi et al. 2020). Global timber demand has a large impact on tropical forests, especially since many tropical countries do not have sufficient financial and infrastructural resources to improve material efficiency and sustainable forest management.

More policy support is needed to encourage the use of waste biomass in building materials.

Increased investment is needed to develop regenerative methods of managing global forests and agricultural lands.  The potential to redirect biomass residues into cost-competitive construction products, such as cementitious binders,  bricks, panels, and structural components, could incentivize more careful and productive management. Compounding benefits include the capacity to store carbon within building materials and products,  thereby reducing climate change emissions from decaying matter, forest fires and the burning of crop waste. Further, major carbon sequestration benefits could come from new cooperative approaches between builders  and  forest  managers  to  increase  the  biodiversity  of forests through the selection of functional attributes for  building  materials  according  to  species  (Osborne  et  al.,  2023)

A promising avenue to alleviate pressure on timber resources is the development and use of reconstituted wood products from non-timber lignocellulosic residues from forestry, agricultural and food “waste.” Today, most of the biomass from agricultural by-products is either abandoned on land (generating greenhouse gas emissions through natural decomposition) or burned (releasing carbon directly to the atmosphere). Within forests, excess biomass residues can feed and exacerbate wildfires (Sahoo et al. 2021). Meanwhile, in urban areas, waste biomass is typically either landfilled or combusted for energy recovery, both of which are more carbon-intensive pathways than converting this waste into valuable building materials (Tripathi et al. 2019; Lan, Zhang and Yao 2022). Scaling biomass residues from agriculture requires a biodiverse and material-efficient approach to avoid worsening the negative environmental and labour impacts of monoculture agriculture.