Rosemary graduated with distinction in Architecture from the University of Technology, Graz (Austria) and the University of Bath (UK) in 2000. Born and raised in Ghana within her family’s construction business, she combines deep local industry insight with rigorous international training—a duality that informs her unique perspective in architecture and cross-cultural collaboration. 

Rosemary co-founded OOA Austria (2003) and OOA Ghana (2006) alongside Martin, establishing a practice renowned for bridging European and African architectural excellence.

She specializes in project management, contract administration, and strategic planning, ensuring seamless execution of complex, multinational projects.

As the Honorary Consul of Austria and Austrian Foreign Trade Representative to Ghana, Rosemary fosters bilateral ties in trade, culture, and architecture, further strengthening OOA’s role in global partnerships.  

Martin Orthner brings a unique dual-qualification background to his architectural practice, having earned distinguished credentials in both civil engineering and architecture. He completed his civil engineering studies with honors at the Federal Higher Technical Institute for Civil Engineering in Salzburg in 1991, followed by architectural training at the University of Technology in Graz, Austria and the University of Bath, UK, graduating with distinction in 2000.

In 2003, Martin co-founded OOA Austria alongside Rosemary, later establishing OOA Ghana in 2006 to create a transcontinental architectural practice. 

Martin specializes in comprehensive design development and technical implementation, with particular expertise in 3D modeling, quantity surveying, and construction cost management. His skills encompass draft construction cost estimation, bill of quantities development, value engineering, and rigorous cost control throughout project lifecycles.