Diana Wellenbrink is an architectural designer that believes that working with a client is a road to take. It is never one and the same with its surprising turns. That keeps the practice evolving.

Graduating from the University of Architecture Civil Engineering and Geodesy in Sofia, Bulgaria, Diana began immediately working on European funded projects. Soon after, she started her own practice and was awarded the Best Interior Design by a leading interior design magazine.

She made her way to the US when the company she worked for with an office based in Sofia invited her to come work at the Seattle Office. Northwest became her home and Diana became a licensed architect in Washington State and LEED AP. She would then spend some time working for a few Seattle architectural firms, including Streeter Architects, which mostly influenced her vision of the architectural practice and its social importance.

“Most impressive and inspiring leaders. As an outstanding architect and an extraordinary man, Mel Streeter left his mark on our community and changed the lives of so many .... As one of the first African-American architects to lead a Seattle firm, Mel broke down barriers and created new opportunities for others who followed.” - Maria Cantwell about Mel Steeter

Diagonal D was started 20 years ago to provide structural design by Bruce Wellenbrink, S.E., P.Eng. When Diana joined the practice in 2011, it evolved the practice, now providing both architectural and structural design, while collaborating with other small businesses or freelancers. When a larger scale project is commissioned, the network of these small studios teamwork to develop the project in timely manner.