AJ Climate Champions podcast: Henning Larsen’s Martha Lewis on how to screen materials for both chemicals and carbon

Launching a new six-part series on materials, Henning Larsen’s head of materials argues that a baseline of health and environmental impacts should inform specification

For the latest series, Hattie Hartman is joined by co-host Joe Jack Williams, partner at Feilden Clegg BradleyStudios and co-editor of their new book, Materials: An Environmental Primer (RIBA Publishing, 2024).

In this introductory episode, Lewis explains why a holistic approach is essential to navigate the nuances of material selection. She describes how the European focus on life-cycle analysis and GWP (global warming potential) of materials is starting to be integrated with the earlier American focus on healthy materials and toxic chemical content.

‘The glut of information is a challenge of our time,’ says Lewis. ‘How do we navigate too much information to make the right decisions?’ She advocates for material passports which would consolidate the relevant data needed to make informed decisions all in one place: carbon emissions, chemical content and circularity. She also argues that certification schemes, despite their weaknesses, are the most effective route to ensuring that a project delivers on its sustainability aspirations.

Lewis also describes Unboxing Carbon, a database with an accompanying course, which she has developed to upskill architects on the carbon aspects of material selection. Lewis has rolled out Unboxing Carbon across Henning Larsen’s 700-strong practice and also offers it to external practices.

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About Martha Lewis

Martha Lewis joined Henning Larsen in Copenhagen in 2003 and took on the role of head of materials in 2018. Martha is a WELL AP, DGNB Auditor, and LEED Green Associate and a member of the Danish Technological Institute’s Advisory Board for Sustainable Building Materials.

She leads materials research at Henning Larsen where she has forged numerous industry partnerships and research, publishing papers on integrating health and toxicity in material specification and comparing Nordic certification systems for their screening of toxic substances. She is currently involved in research looking at the chemical content, indoor air quality impacts and global warming potential of household paint.

Martha has led the development of Henning Larsen’s Unboxing Carbon, an open-source database on the practice’s website. She teaches Unboxing Carbon in a workshop format where participants open a box of 20-plus material samples and try to arrange them in the ascending order of their carbon footprint. She is currently developing Unboxing Chemicals, a similar database for screening the chemical composition of materials, due to launch later this year.

Martha recently joined the board of revalu, a Hamburg-based materials data platform.