Greg Zahn holds a 5-year professional degree in Architecture with a minor in Civil Engineering from the University of Notre Dame. Greg has over 25 years experience in the construction business, beginning as a laborer working on high-rise buildings in Chicago. As a member of the architectural design team for Wisconsin's largest contracting company, he worked closely with estimators, schedulers and project managers. This experience gives Greg a great understanding of and appreciation for how design works in the field.

At the request of the Mayor, Greg serves on the D.C. Building Code Advisory Committee (BCAC). The Committee coordinates improvements in the D.C. Government’s permit processing, permit enforcement and construction inspection procedures. Greg has been professionally licensed in the District of Columbia since 1988, Virginia license pending.

David Zahn is a graduate of the Milwaukee School of Engineering, holding a B.S. Electrical Engineering and A.S. Electrical Communications Engineering. David left Sprint Cellular as Director of Engineering to establish Pinnacle Towers Inc. as Vice President where his responsibilities included engineering, construction, site security, network monitoring, FCC compliance, land acquisition, zoning and permitting.

David’s engineering background provides Zahn Design a unique advantage in coordinating mechanical, electrical, and plumbing (MEP) drawings with consultants. Many MEP drawings are produced in-house and reviewed and certified by outside consultants, saving clients additional engineering fees.

Christina Hayunga has over 10 years experience working in architectural firms in the Washington, DC area on various residential, religious, institutional, and commercial interior projects. She received a five-year professional degree in Architecture from The Catholic University of America in Washington, DC and before joining ZDA, worked at several local firms including Gensler, one of DC’s leading interior design firms on various workplace interior projects in the metropolitan area. Christina has experience in high-end tenant build-out projects and historic renovation projects and enjoys coordinating design efforts among the various consultants on large projects.

Christina also volunteers with the Architecture in the Schools Program that puts local architects in DC public school classrooms each semester to introduce students to the exciting world of architecture. She is a registered architect in the state of Maryland, a member of the American Institute of Architects and past board member of the AIA-DC Chapter.

Bill Chang received his professional degree in Architecture from Feng Chia University in Taiwan.  Since coming to the U.S., Bill has also earned Masters degrees in Civil Engineering, Engineering Management and Computer Sciences, and with those credentials, he is an invaluable part of the project team. Bill works closely with project managers and engineers to help facilitate the MEP designs for each project.

Fluent in Manderin and Taiwanese, Bill also enjoys bowling and volunteering with local community groups. Most recently, Bill has been assisting his church in the design and development of CAD drawings for their new sanctuary.