Barriers to bio-based buildings
In our first article, we highlighted changes in ESG that were promoting bio-based materials and practices. Without question there is a newfound interest in building materials that are more local, minimally processed, regenerative and health-promoting. In many respects, construction and real estate seem to be “catching up” with credentials promoted in other industries.
Despite the enthusiasm for – and greater use of – bio-based materials, many hurdles remain. Planning and regulation, supply chain readiness, developer reluctance and practitioner scepticism all tend to frustrate their widespread adoption. In this, our second article in the series, we examine these barriers - and how they may be changing.
Challenges to greater uptake
The generally risk-averse construction industry has yet to embrace bio-based materials on a large scale. Whether it is questions about flammability and durability, or simply familiarity with conventional products, the adoption of bio-based materials will take time. It is understandable, given concerns about health and safety – not to mention regulatory compliance – that the route to market would be a cautious one.
There are many more hurdles to mortgaging and financing bio-based projects than those constructed with conventional building materials. Chief among these are regulation and conventional business practices, especially as they relate to insurance (underwriting). Even as net zero carbon drives timber and other bio-based materials into buildings, regulation in the UK (particularly fire and building regulations) limits their (widespread) use. Historically, insurers have been unwilling to underwrite timber-framed buildings. The duo of regulatory restraints and market hesitancy is a difficult combination to overcome.
Currently, regulations don not allow timber cladding on buildings above 18m. While this ostensibly covers the façade, in practice it has also dampened enthusiasm for timber framed buildings in general. Although other countries build tall buildings using timber, in the UK this has not happened on a large scale.
When it comes to plant-based materials, objections extend beyond fire. Water damage is as important as combustibility in discouraging plant-based materials. Timber is viewed as more susceptible to water damage to finishes, delamination and structural deterioration. Both fire and water concerns contribute to uncertainty about timber’s safety and integrity.
Regulation and best practice are changing
There appears to be momentum in both regulation and best practices (first internationally and now in the UK) that favours wider adoption of bio-based materials. Beginning in 2022, France required all public buildings to be composed of 50% or more bio-based materials. The mandate can be fulfilled by bio-based materials made from matter derived from living organisms such as hemp and straw and applied to buildings constructed for the 2024 Paris Olympics complex.
It is no coincidence that France is also the first country to have regulation around embodied carbon. France’s RE2020 regulation requires that developers produce and report a life-cycle analysis that details carbon from materials and construction – the wrong carbon profile at planning can doom a project. This is widely seen as a driver of demand for bio-based materials of all types (and not just timber), since meeting the standards will require non-conventional materials.
Even in the UK, there is a movement afoot among various Government agencies (DEFRA and DESNZ) to actively promote timber in construction. Added to this, some insurers have begun to expand underwriting of engineered timber for commercial buildings. The appetite for insuring bio-based materials appears to be increasing, albeit slowly.
The role of whole life carbon assessments
Ten countries in Europe have introduced regulation on whole-life carbon emissions, addressing both embodied carbon and operational emissions. Not surprisingly, a strategy of choice – often mandated – is the use of timber and bio-based materials for buildings.
The European Performance of Buildings Directive (EPBD), best known for introducing energy performance certificates (EPCs) into the UK, is undergoing revision. New changes in regulation are likely to incorporate the reporting of whole life carbon emissions in the next few years. This could change the way embodied carbon is addressed at a European scale. If it does, bio-based materials are very likely to be products of choice for meeting new measurement and reporting categories.
The lack of embodied carbon regulation in the UK on a national scale fails to focus attention on the impact of embodied carbon and the potential benefits of bio-based materials. Indeed, interest in timber in the UK comes mostly from companies employing voluntary net zero carbon frameworks.
That is why the recent work by DEFRA and other Government agencies in promoting timber appears more hopeful, as does the possibility of changing building regulations to include embodied carbon (the so-called “Part Z”) in building regulations. Should more net zero carbon standards be required (including embodied carbon regulation) the experience of other countries suggests that bio-based materials will be the route to regulatory compliance.
Barriers are lowering, albeit slowly
There is initial evidence that the insurance industry is becoming at least a little more comfortable with the idea of using more bio-based materials like timber. There is also increasing pressure on insurers to change practices as bio-based materials become more attractive in a carbon-constrained construction industry.
The same hurdles that timber faces also apply to other bio-based materials like straw, cob, thatch and so on. Typically classified as “non-standard” construction, it may be possible to get insurance and underwriting from some specialist companies. However, it is more difficult and expensive to get insurance for buildings where plant-based materials comprise the façade, the structure, or both.
Likewise, there has been movement in the insurance industry. The tenor of the debate has changed as it becomes clear that traditional modes of building and underwriting may not be sufficient to address issues of whole life carbon in buildings. It is not surprising that there is still a reluctance among conventional players to take on risks. But some larger firms are softening their approach to insuring timber buildings – this is bound to continue.
In our third and final article, we will look at hour wider changes in ESG are further challenging regulation and conventional business practice. Looking backward at recent developments and projecting forward, we suggest both bio-based materials and processes represent a risk-reducing, value-adding trajectory for the future.
