Award-winning or headline-grabbing sustainable homes often showcase heat pumps, solar panels, or greywater systems. But there’s another, simpler product behind many of these designs: clay brick.
While standards like Passivhaus and BREEAM are relatively new, the sustainable properties of clay brick have evolved over more than 6,000 years. Manufacturers like Michelmersh continue to improve brick’s sustainability profile, making it a versatile choice for projects of any budget or scale—from large housing developments to bespoke extensions.
If you’re designing or specifying for more sustainable homes, here’s what makes clay brick such a smart choice.
What makes clay brick sustainable?
Those in the built environment will know clay brick for its strength, weather resilience, and A1 non-combustible rating. But its sustainability credentials are equally impressive:
- Minimal operational carbon: Clay brick’s durability means buildings require little to no maintenance over their lifetime, contributing to low operational carbon emissions.
- Highly durable: Through a process called partial vitrification, bricks become strong and highly water-resistant. This makes them more resilient to freeze/thaw cycles and gives them an exceptionally long lifespan.
- Thermal performance: Thanks to its high thermal mass, clay brick helps regulate indoor temperatures—cooler in summer, warmer in winter—reducing energy use and associated emissions.
- Reusable and recyclable: Durable enough to be reclaimed, whole clay bricks can be reused in new builds. Even damaged bricks can be crushed and recycled, helping reduce reliance on virgin materials.
- Locally sourced: Clay is abundant, with most countries able to source it locally. At Michelmersh, 85% of raw materials are sourced within 2.5km of our factories, cutting emissions from transport and giving our bricks a distinctive, site-specific appearance.
Brick habitats: encouraging biodiversity
Biodiversity- the rich mix of plants, animals, fungi, and bacteria in ecosystems- under pins natural resources, food systems, and wellbeing. But construction, among other pressures, contributes to habitat loss.
Innovative brick designs now offer nesting spaces for keystone species like sparrows, bees, bats, and starlings. These brick habitats can be built into new homes or retrofitted to existing buildings, enhancing biodiversity without compromising design integrity.
Lower carbon bricks: recycled content and alternative fuels While clay brick’s operational carbon is low, embodied carbon—the emissions from producing materials—remains a challenge. One solution is incorporating recycled content. For example, our Blockley Porcelain White Smooth contains 44% recycled porcelain from sanitaryware, significantly lowering the carbon impact of raw material extraction. We’re also developing ways to de materialise bricks, using thinner profiles or more perforations to reduce material use.
Reducing the carbon intensity of manufacturing is also key. Firing and drying stages are the most energy-intensive, typically fuelled by natural gas. Michelmersh’s HyBrick™ trial, using green hydrogen, cut emissions during production by up to84%—all while maintaining the technical performance of our bricks. While still in development, projects likeHyBrick™ points to the future of low-carbon brickmaking.
