About Us


a dynamic group of designers. Design Effect International is an Interior design consultancy, established in 2002 by Diane (Heeger) Thorsen in Johannesburg South Africa. Having collaborated successfully over several projects, Diane relocated to Dubai establishing an international presence.

Diane, now the Design Director and a Principal of Perkins + Will Dubai, collaborates with the Design Effect Studio on projects internationally. In 2012, Justin Cooper, with experience in the Interior Design Industry since 1996 stepped into the role as Managing Director of the South African operation.

Design Effect International and Perkins + Will now stand as powerful forces each in their own right, but with mutually beneficial ties between the two design studios.


Design: This is the essence of our practice, and what we are born to do.

Innovation: Knowledge, learning and research are the spirit of our firm.

Sustainability: Our respect for the natural world motivates everything we do.

Collaboration: We believe in the power of teams.

Social Purpose: The result of our work is to advance social well-being.

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