Developing next generation construction materials

Demand for alternatives

As the environmental costs of traditional materials have become more widely recognised, the demand for sustainable alternatives in construction and manufacturing has risen. Unfortunately, this shift has not been swift enough - we need to accelerate the transition to sustainable steel, concrete and wood, particularly in countries where shortages drive up prices, imports or environmental damage.

Composite wood materials made from Cross Laminated Timber and Mass Timber, are already servicing some demand for these sustainable materials but, as we’ll cover later in this article, have constraints that limit their ability to deliver impact in the sustainability of construction and manufacturing sectors, and interfere with the long term reestablishment of primary forests. 

It’s worth noting that, on top of construction materials, there are a variety of other economically valuable commercial and consumer items currently built with wood or plastic that have the potential to be swapped out with more sustainable alternatives. Ideally, innovation within this area would cover a materials spectrum across both construction and more general items, using similar platform technology.

The problem with construction

Construction presents numerous environmental challenges. On one hand steelmaking is highly emission-intensive and the nearly 2 billion tonnes of steel produced every year generates around 8% of global CO2 emissions. On the other hand, when faced with a lack of available steel shortages, construction companies may use wood, indirectly encouraging increases in local logging operations to fill the void, thus reducing the carbon drawdown potential of forest ecosystems. 

There is a lack of suitable alternatives to structural steel for low- mid- and high-rise buildings in many parts of the world, with construction materials such as steel and timber often needing to be imported. Together, dependence on these materials acts to destroy useful ecosystems, drive carbon-intensive production, or carbon-heavy import and export. 

Countries where the demand for wood can outstrip supply, which also coincides with a dependency on foreign steel or iron ore imports (China, Saudi Arabia and much of Latin America), could seriously benefit from alternative, locally produced construction materials. In the post-pandemic world, where global supply chains are strained (and steel and timber prices have risen in response!), countries are increasingly thinking about domestic self-sufficiency for these materials. While there are promising steps in the right direction for “greener steel”, this may not always be the best solution. Indeed, there is no guarantee that the technology can come online fast enough, in enough places, to achieve the positive biodiversity and ecosystem service outcomes that grown materials could.

Existing alternatives: Promises & limitations

Mass Timber (MT) and Cross-Laminated Timber (CLT) are promising alternatives to steel, especially for the construction of low- and mid-rise buildings. Both are terms that relate to composite woods of different categories, and both (especially CLT) are slowly starting to find acceptance in the construction sector, even at international levels. CLT uses fine layering of different woods to create structural elements with a higher tensile strength than steel, high fire resistance, and lower carbon footprints. In addition, the high degree of prefabrication of off-the-shelf structures makes it an ideal solution for developers, shortening projects and driving higher profitability, by enabling convenient transportation and fast installation. 

However, CLT is not without its constraints. There has been slow adoption by construction companies due to a lack of experience amongst construction crews, and issues with charring in fires, meaning that CLT market growth is expected to reach only $3bn by 2028 (in comparison to the Green Building market, which is expected to grow from $217bn today to $384bn by 2025). These issues remain active despite enabling regulations and standards supporting adoption by the construction industry. 

Adoption of CLT’s will likely accelerate in construction, as constraints in experienceare overcome. However, additional constraints in manufacturing processes, technology and versatility also need work. As such, we believe there are two intermediate markets that will allow profitable technical development of new CLT techniques: Transport pallets and wooden furniture, both big markets with a forecast market size of $98bn and $370bn respectively by 2028. Provided that costs can be lowered and improvements made for these specific use cases, the lower regulatory requirements would drive faster adoption of the materials, which could be diverted to construction as the market demand increases.

However, we believe the most fundamental constraint that needs to be overcome in CLT is the fact that its production is reliant on trees being felled. This runs counter to our belief in restorative cultivation. If we can simultaneously develop techniques to source inputs that are not reliant on felling trees, CLT could deliver impact in sustainability of materials and the protection of primary forests.

Keeping trees in the ground

It is generally perceived that paper and wood products coming from renewable forests has been a good outcome for the planet. This view of harvestable forests does not take into account the low levels of biological diversity that tree monocultures support. In contrast, primary forests, which are old growth forests with dense vegetation and high-levels of biological diversity, have greater resilience, support more lifeforms and provide superior ecosystem services.

Fast growing tree farms used for wood production have little of this complexity. Even where natural forests have been regrown on previously farmed land, the process of becoming primary forests can take centuries, and sometimes millenia. A regrown forest can typically only become secondary forests within a human lifetime - a state characterised by trees and species of similar sizes, without that competition-driven complexity. 

The only mechanism for maximising primary forest coverage, is to ensure that as many mature trees stay in the ground, for as long as possible.

Wood without trees

This begs the question, while cross-laminated timber is potentially a great sustainable material, where are we going to source the wood from?

One proposed wood source, bamboo, could be an answer for land that has already been extensively degraded by agriculture. It has the desirable properties of fast growth (reaching maturity within three years depending on the species), low agronomical maintenance (can grow in abandoned plantations), its tensile strength is higher than steel when processed appropriately, and it can be grown in soils not suitable for agroforestry or agriculture, whilst regenerating them for more productive uses in the future. Bamboo has already been used within CLT as a construction material. This same product could be directed toward non-construction uses such as intermediary products (e.g. pallets). 

The follow on questions then become, if bamboo can work, what other plants, herbaceous material could be diverted to this use case? Could biological waste be turned into wood products independent of land-based growth cycles? And what would need to be true to turn widely available or cultivable and sustainable material into cheap, high-performance woods?

The trick in achieving this versatility of use cases and materials likely lies in the correct use of multiple different technical approaches and identifying the limitations to turning particular materials into wood or wood-like materials. There are several options:

Naturally sourced polymers can be used to enhance the strength of the composites of all types - especially fabrics and enhanced plastics - but this is generally investigational and not widely deployed in wood engineering, which typically relies on single boards adhered together. Polymers and adhesives have been sourced from traditional chemistry and biological sources, and there is ample room to enhance biologically sourced materials from microbes (and more), alter their design with machine learning approaches, or design novel polymers and adhesives from the ground up. 

A dialable process for treating different grades of timber already exists, as do various processes for obtaining these from different wood materials, but the same cannot be said for composite woods derived from other plants, including bamboo, which has had significantly less research, despite its overall promise. Prefabricated (prefab) approaches for CLT have proven useful for enhancing the value proposition for construction, but no provider that we are aware of currently offers full prefabrication of construction-grade bamboo composites for anything other than single-storey homes. Whilst there are low-rise prefab providers of bamboo, their complexity is limited and there exists an opportunity to grow into more complex markets through more tunable compositing processes. 

Lastly, taking inspiration from the capabilities of cellular agriculture might even allow the development of enhanced properties not present in sourced materials, such as using microbes to manufacture fire/char-proof resin layers to overcome the issue of charring that currently holds back CLT from greater adoption.

Create ventures with us

Within this area, we’re aiming to identify novel wood sources and composite manufacturing approaches to provide alternative wood materials to be used in multiple sectors. This will allow us to reduce the importation of steel and lumber, reduce the number of trees felled and enhance a return to primary forests. 

This opportunity area will be part of our Tropical Agriculture & Bioeconomy Initiative based in Costa Rica, a country with a breadth of climate zones supporting 4000 agricultural products and their waste streams that have already provided the foundation for a rapidly growing biomaterials science sector. Not only does Costa Rica serve as an ideal testbed to develop novel biomaterials from these diverse inputs, but it is one of the only countries to have successfully reversed deforestation despite a shortage of timber and rising demand for construction materials and wooden pallets to support its growing agricultural export sector. Like many other nations, Costa Rica’s construction and materials sectors would benefit greatly from innovative domestically-produced materials, making the country an excellent location for both research and development, as well as early market launches before product expansion to similar larger markets and biomes, such as Mexico and Colombia. The opportunity area will receive support from the Biomaterials Hub being built at the Costa Rican Investment Promotion Agency (CINDE).

If this is an area of interest to you and you have experience with biomaterials or chemical engineering, we want to hear from you! More details on the specifics of this role can be found in this job description.

More details on the Tropical Agriculture & Bioeconomy Initiative can be found here.