Siri Zanelli, Founding Partner of Collective Works, shares practical lessons from specifying natural materials, exploring how architects can overcome barriers relating to cost, regulation, construction methods and client expectations.

Moving beyond ambition

For Siri Zanelli, specifying natural materials should be an ordinary part of architectural practice, rather than an exceptional undertaking. But achieving this in the UK can be surprisingly difficult. Drawing on her Norwegian background, where timber construction is commonplace, Zanelli questioned why natural building materials are frequently treated as unconventional alternatives in Britain.

She illustrated this through a series of projects, beginning with the relocation and reuse of a traditional log building in Norway, made possible through local knowledge, readily available skills and straightforward construction methods. By contrast, projects in London exposed the barriers created by perceptions of risk, fragmented design responsibilities and unfamiliarity with natural building systems.

In one project, a proposed timber extension was replaced with conventional construction because of concerns about mortgage availability. Another, involving the deep retrofit of a family home, revealed how specialist design responsibilities could become unnecessarily complicated, reinforcing the value of simple, well-understood construction methods.

Zanelli also addressed the challenge of persuading clients to invest in natural materials. While embodied carbon assessments are valuable design tools, she suggested that the benefits of comfort, indoor air quality and health can be more persuasive. Her message was that successful specification depends as much on communication and education as technical performance. Clients and contractors need to understand why particular materials have been chosen, and why apparently equivalent substitutes may not deliver the same benefits.