How the right building materials can support biodiversity

Emily Landsborough, Head of ESG at Ibstock, discusses the steps housebuilders and building manufacturers are taking to safeguard the UK’s biodiversity and protecting a beloved British bird facing extinction. 

Few sights or sounds are more emblematic of the British summer than the scream of swifts soaring across the sky. They are renowned for their brown plumage, contrasting with the white colouration around their throats, and their distinctive call. But the swift’s population numbers have plummeted by 60% from 1995 to 2020. The British Trust of Ornithology reports that breeding pairs are set to fall below 40,000 in 2025, with nesting habitat loss identified as the primary cause. 

Historically, swifts tend to live in old houses or churches, squeezing through tiny gaps to nest inside cavities in roofs and walls. As older buildings are renovated and soffit gaps closed up, swift nest sites are rapidly disappearing. For this reason, swifts were added to the red list in the UK’s 2021 Conservation Status Report, identifyingthem as critically endangered.  

Author and campaigner Hannah Bourne-Taylor has long championed the swifts’ cause. Her petition for mandating swift bricks as a solution to the lack of cavity nesting habitats became the fastest growing petition of 2023. Hannah explains: “Without swift bricks, there is no guaranteed nesting habitat for cavity-nesting urban birds anywhere in the UK. It is no exaggeration to say that housebuilders would be the saviour of swifts in the UK if they proactively specified swift bricks across their developments. And what a fantastic prospect that is: becoming the custodian of one of the UK’s most beloved species.” 

Industry-wide action 

As a sector, we have the unique opportunity to create cavity-nesting habitats as we build. Swift bricks provide a nesting habitat for eight species of birds, from iconic swifts to blue tits and house sparrows. Swift bricks ensure species survival and create an invaluable legacy, preserving our most accessible daily touch point to nature: urban birds.  

Gibraltar added a swift brick planning policy 30 years ago, and their swift populations have stabilised. The Netherlands mandated swift bricks in their equivalent to Building Regulations in 2024. There is a British Standard (BS 42021:2022) specifically for this measure that provides necessary guidance and flexibility for developers. However, we question whether it is enough to save red-listed birds. According to the 2023 State of Nature report, one in six species faces national extinction, including 43% of birds. 75 British birds are currently on the Red List, but we are uniquely positioned to save this whole category of cavity-nesting birds. Site loyal, once swifts and house martins move into their swift brick, they will return year after year to the exact brick. As an industry, we can create a legacy for generations to come, benefiting from the connection this measure gives us to nature. 

We are seeing positive signs that key industry stakeholders are taking affirmative action. The Future Homes Hub, a coalition of businesses across the housebuilding supply chain, has committed to promoting biodiversity and advocates the specification of swift bricks. So far, 20 housebuilders, collectively building over 90,000 homes per year, have committed to the Hub’s pledges, which include adding one nesting brick in every new home built, alongside other ecologically considerate steps. The commitment applies to all new development proposals submitted after September 2024 and goes above and beyond the existing Biodiversity Net Gain regulations. 

At Ibstock, we have significantly invested in our EcoHabitat range of product, which includes our Swift Box carefully designed to meet newbuild and retrofit applications. Available in clay and cast stone, it is mortared into the external leaf of a cavity wall to create a secure, weather-resistant and attractive finish. It is accessible to Swifts, as well as eight other British birds, including Blue Tits and House Sparrows. The range also includes a Bat Box, Hedgehog Concrete Gravel Board, Bee Habitat Brick and a Sparrow and Starling Box. These products help protect and support critical wildlife while maintaining our homes’ integrity and aesthetic appeal so homeowners and wildlife can coexist safely.  

www.ibstock.co.uk