I started this thesis project with my curiosity of the idea of layering. This idea has been used in everywhere from computers, fashion to culinary. How about the idea of layering in architecture? I studied the idea of layering in geology. I chose it because I believe geology is very close to architecture in term of physicality, even form and space. We could not separate architecture and geology; architecture inhabits geology. I decided to focus on one most important idea of layering in geology and most interesting for me: the idea of stacking. If we look back to the ancient building, stacking is the basic system to build a building. And for me it is very interesting to see the possibility to apply this idea with all new materials and technology that we have now. In this project I tried to experiment to do stacking from several different materials: concrete, stone, glass, and wood. The project is a health club located in an urban fabric of Georgetown, Washington D.C., between M Street and Potomac River. The site has potential to create a better connection between the lively street of M Street and Potomac River which will be developed in the future. As a private building in an urban area, the building should be able to accommodate urban needs of its surrounding. Therefore the relation between the layers of public and private become very important issue in this project. The building, which program is basically exercise rooms and baths, is expressing the idea of stacking of public and private layers. The running tract area on the second floor and the roof garden on the roof top of the building are accessible to public. Then the building is pushed to one side of the site to create a plaza for a better access from M Street to the riverside. Most idea of stacking in this project applied horizontally because I studied the idea of stacking in geology which is more horizontal than vertical. / Master of Architecture