At the end of September, we hosted our first CPD event in collaboration with Margent Farm in Oxfordshire. We were lucky enough to have some fantastic speakers presenting, Jeremy Blake, Graham Durrant and Professor Tom Woolley. Although we recorded the presentations, we thought it would be a great idea to highlight the key points of each talk, beginning with Tom. 

As a former Professor of Architecture at Queens University, Belfast, a multi-published author and editor of the award-winning Green Building Digest, Tom has more than a few credentials. He is currently a researcher at Rachel Bevan Architects in Belfast, Northern Ireland. He is excited by hemp beyond design and construction, also in its regenerative farming capacity.

However, the uptake of bio-based materials in the UK has been challenging. Misinformation and misguided energy initiatives combined with a lack of education and industry bodies representing bio-based materials have been root barriers. Tom delved into some of these issues.

Industrial Scale

Tom has worked with hemp in many capacities, including large-scale urban projects (2.38 – 3.00). These projects highlight how we can successfully implement hemp in mainstream construction. This point is relevant to mention. People claim, ‘it’s all very well doing these “hippie houses” in the countryside, but hemp is not suitable for mainstream construction.’ Tom reinforced this is not the case, pointing to Parisian projects, with ‘quite a number of buildings being built’ using hemp-lime and steel frames. (4.55 – 5.17)

Mainstream not Convinced

Tom’s experience in Ireland suggests great enthusiasm around hemp but also how mainstream embracement of hemp is lacking. The case in question was the Ballymun Rediscovery Centre for recycling in North Dublin. Efforts to build a wholly sustainable centre were unsuccessful. The belief in hemp’s capacity to insulate and protect against moisture was not shared by everyone involved (9.03 -11.17). Tom noted it is not just the mainstream that needs to be convinced, but some aspects of green campaigning. (14.45 – 56)

Misconceptions and Paranoia?

These are partially rooted in administrative action plans to decarbonise, meaning total dependency on electricity. (16.50 – 17.15)

Combined with current building standards, this severely obstructs the mainstream adoption of bio-based materials.

Building Safety Act

A further misconception radiated in the aftermath of the Grenfell Tower tragedy in 2017 and the UK’s 2022 introduction of the Building Safety Act. The most hard-hit sector is the cross-laminated timber industry (CLT). ‘It has been decreed that wood is flammable, so, therefore, we can’t use it anymore, but anybody who knows about cross-laminated solid timber knows you’ll have a hell of a job to set fire to it.’ Tom mentions additional challenges posed by the Building Safety Act, caused by a lack of a ‘strong industry body representing the interests of biomaterials’. (20 – 21.05)

It is distressing because the evidence for biomaterials is strong. Tom says that Norway offers a great example of large multistory buildings constructed from timber. (22.50 – 57)

Jammed Hemp Initiatives

In addition to CLT, hemp comes up against opposition as well. In Tom’s work, he has experienced stringent attitudes opposing hemp, particularly regarding fire safety. The LABC and LABSS provided certification for hemp in one of Tom’s projects in Dumfries and Galloway, Scotland, only to rescind it in response to the Building Safety Act. (21.40 – 22.00)

War with Petrochemicals

Standards

Considering construction UK standards, Tom highlighted the attention to airtightness and fire safety promoted by these organisations, favouring petrochemical materials, with biomaterials assumed to be ineffective. (24.45 – 26.15) 

Petro Power 

Our dependence on petrochemicals was made abundantly clear by the level of outsourcing from the UK and Ireland for polyurethane and isocyanates. These chemicals are sourced from great distances, as far as China, for making foam insulation. This process involves pollution, and economic cost from transport, and several chemicals used in this material production are also illegal (CFCs). The reported use of slave labour is also a considerably worrying concern. 

 Tom’s presentation indicated that there is little effort to disguise these illegal practices, showing the true power of the petrochemical industry. (28.10 – 31.10)

Retrofitting Right

The UK’s government retrofit policy ignores materials. Yet, the need for retrofitting is critical. Current schemes are unsustainable and harmful to human health. Tom presented several images of mould, which had formed and thrived behind dense plasterboards and soft insulation used in retrofit schemes. As you may have guessed, the mycotoxins that flourish within are toxic. Hemp poses a solid countermeasure to mould. Tom showed us his home experiment, where he placed hemp block samples around his conservatory, where condensation on the glass was rife. Within 24 hours, the condensation had entirely disappeared. An excellent example of hemp’s moisture retention capacity! (35 – 44)

Hemp Cowboys

Finally, among the many barriers to hemp are hemp cowboys, offering homeowners flawed advice on building with hemp. Sadly, when the project inevitably suffers, yet another story of hemp’s inefficiency as a construction material is released into the debate. 

It may seem pessimistic to discuss the current barriers hemp comes up against, but the tide is turning. This year has been great for Hemspan as a company but also for hemp in general. Ultimately we were uplifted by the examples of work and projects achieved. We will be talking about Jeremy’s presentation next week. In addition, the audience’s enthusiasm for using hemp in construction was uplifting. It instilled our belief that we’re in the right place at the right time… The future is hemp! 

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NB: The bracketed numbers are the quoted timing spots in the presentation.