The built world tells a story of a bygone era; monuments to construction methods that once served us well, but now weigh heavily on our planet. Yet, here there is an extraordinary opportunity – a chance to not just renovate, but to reinvigorate, to breathe new life into old spaces, and in so doing, cultivate a green future and sequester carbon. This future might just be grown.
Imagine a world where our homes, our offices, our schools are insulated not with synthetic materials, but with materials born from fungi. This isn’t science fiction; it’s the imminent reality of mycelium-based building materials, poised to unlock the monumental potential of retrofitting and propel us towards a truly sustainable age.
Our global commitment to a Net Zero future demands a radical reimagining of our existing infrastructure. From Glasgow to Tokyo, London to New York, the vast majority of buildings that stand today will still be in use for decades to come. To ignore them is to surrender our climate goals and squander all the embedded carbon already used.
The statistics are stark, and they paint a picture of immense opportunity. For instance, an astounding 80% of UK buildings that will be occupied in 2050 have already been built, representing not a problem but the largest construction project of the century. The retrofit market alone is a colossal economic engine, with projections indicating it could exceed £500 billion for domestic housing alone over the next decade, with further trillions waiting to be invested globally in making our existing structures sustainable.
Millions of homes worldwide lack adequate insulation, bleeding energy and contributing relentlessly to carbon emissions. In the UK, for example, 90% of solid wall homes remain uninsulated, despite over 70% of cavity walls and lofts having some form of insulation. Mycelium offers a direct, elegant, and bio-intelligent remedy to this pervasive inefficiency. The burgeoning global market for mycelium in construction is a testament to its disruptive potential, poised for exponential growth as the world wakes up to its benefits.
So, what makes mycelium – the intricate root-like structure of fungi – so revolutionary for retrofitting? It’s a remarkable fusion of nature’s ingenuity and cutting-edge biotechnology. By growing mycelium on agricultural waste, like hemp shivs, we create a bio-composite that boasts an array of unparalleled characteristics.
Mycelium panels are incredible insulators; studies show their thermal conductivity can be as low as 0.039 to 0.05 W/mK. To put that in simpler terms, this number measures how well a material stops heat from escaping (or getting in), and a lower number means it’s a much better insulator. This impressive resistance to heat flow means they trap heat in winter and keep buildings cool in summer, slashing energy consumption and bills.
The natural, porous structure of mycelium makes it an excellent sound absorber, with research indicating acoustic absorption coefficients of up to 99% at 1,000 Hz. What this means is that the material can soak up almost all (99%) of typical sound frequencies, like human speech (1,000 Hz), preventing echoes and making spaces much quieter and more comfortable. This transforms noisy urban environments into peaceful indoor spaces.
Unlike many synthetic materials that can melt or ignite, mycelium tends to char when exposed to fire, forming a protective barrier that enhances fire safety by slowing combustion and releasing non-toxic fumes. These aren’t inert, off-gassing materials; mycelium panels are bio-based, naturally breathable, and contribute to superior indoor air quality, free from harmful volatile organic compounds (VOCs). These are invisible gases released from everyday products and materials like paints or glues, which can negatively impact health. Healthy buildings, healthy people.
Furthermore, being lightweight, adaptable, and limitless, they are easy to transport and install, and can even be grown into bespoke shapes, offering architects and builders unprecedented design flexibility for complex retrofit challenges. This isn’t just about reducing a carbon footprint; it’s about transforming buildings into healthier, more comfortable, and truly regenerative spaces.
Decarbonising our built environment is a monumental undertaking. While renewable energy generation and low-carbon heating systems like heat pumps are crucial, the most impactful and often most cost-effective first step is to drastically reduce the demand for energy. This is the essence of the “Fabric First” approach. A building with poor insulation is like a leaky bucket; no matter how much energy you pour in, it will constantly escape.
By prioritising the building’s envelope, we significantly reduce energy consumption, making any heating or cooling system dramatically more efficient. Superior insulation not only cuts energy bills for households and businesses, with internal wall insulation alone potentially saving a semi-detached home up to £405 annually but also reduces the strain on electricity grids during peak demand.
Critically, it also reduces CO2 emissions by up to 2,100 kg per year – that’s equivalent to driving the average UK car nearly 10,000 miles! Crucially, it translates into healthier indoor environments, fewer cold-related illnesses, and a lighter burden on public health services, with potential NHS savings of £2 billion by 2030 – enough to fund nearly 50,000 additional nurses for a year.
Critically, failing to properly insulate our existing building stock will force us to generate far more renewable energy, at a much higher cost, to meet the inflated demand of inefficient structures. Investing in robust, long-lasting insulation like mycelium panels is thus a strategic economic decision, not just an environmental one.
While the principles of retrofitting with mycelium apply universally, some regions are uniquely positioned to lead this charge. Take, for instance, Newcastle upon Tyne in the North East of England. Their world-class bio-fabrication expertise at Newcastle University’s Hub for Biotechnology in the Built Environment (HBBE) lead in pioneering building futures. It’s a blueprint for global application. Every city, every nation with a legacy of existing buildings and a commitment to Net Zero has the potential to harness this bio-intelligent solution.
The opportunity before us is clear: to not just repair the past, but to grow a truly sustainable future. Mycelium offers a visionary yet practical pathway to radically transform our built environment, making it healthier, more efficient, and fundamentally regenerative. By embracing this bio-intelligent approach to retrofitting, we can unlock immense economic value, create green jobs, and make a tangible stride towards a Net Zero world. Let us seize this moment. Let us grow a greener tomorrow, one mycelium panel, one reimagined building, one more sustainable community at a time.
Where next? Use the links below:
Snippets: Curated collection of short, impactful articles and inspiring ideas.
Forward Futures: Actionable essays delving into contemporary issues.
Grasp the Nettle. Table of Contents: A book in progress charting paths toward a more empowering future, for a global audience.
About: Our mission – From Awareness to Action.
Sources and Further Reading:
UK Building Stock Statistics: Look for reports from the UK government (e.g., Department for Energy Security and Net Zero, Department for Levelling Up, Housing and Communities), Office for National Statistics, or bodies like the Energy Saving Trust on the proportion of existing buildings in 2050.
Retrofit Market Value: Consult market analysis reports from construction industry bodies, financial institutions, or specialist energy efficiency consultancies.
Insulation Statistics: Refer to data from the Energy Saving Trust, government energy efficiency surveys, or academic research on current insulation levels in UK homes.
Mycelium Thermal/Acoustic Performance: Seek out peer-reviewed scientific papers or technical reports from universities (like Newcastle University’s HBBE), research institutes, or companies specializing in bio-materials. These would provide detailed specifications for W/mK and acoustic absorption coefficients.
Home Energy Savings & CO2 Reductions: Data often comes from energy efficiency advisories (e.g., Energy Saving Trust, UK government guidelines on insulation benefits).
Car Emissions Data: Official government statistics on average car emissions (e.g., Department for Transport in the UK).
NHS Savings from Healthy Homes: Reports from public health bodies, academic studies on the link between housing quality and health, or government impact assessments.
NHS Nurse Salaries: Official NHS pay scales or reputable salary data providers.
Mycelium Construction Market Growth: Industry reports from market research firms specializing in sustainable materials or construction.