Sarah Castle is an architect and co-founding director of award-winning practice IF_DO. Since establishing the firm in 2014 with partners Al Scott and Thomas Bryans, Sarah has guided IF_DO to significant recognition, including a 2021 BD Young Architect of the Year shortlisting and placement on Architects' Journal's 40 Under 40 in 2020.

Sarah believes that spaces should be welcoming and accessible to all. She is an expert in social infrastructure projects, and in 2024, her practice won a national Civic Trust Award for the Brent Cross South primary substation. She has headed the design team for The Observer Building retrofit and contributed to the wider Hastings Commons since 2019.

Championing inclusivity in the built environment, Sarah is a founding member aof Part W, a campaign group advocating for gender equity in design.