<![CDATA[The continued growth of the Faculty of Sustainable Development at Institut Teknologi Kalimantan (ITK) and the increasing complexity of its academic and administrative activities have created a greater need for functional, comfortable, and sustainable workspaces. This study aims to optimize the interior design and spatial organization of Building C by identifying existing spatial deficiencies and developing design interventions based on functional, environmental, and sustainability considerations. A descriptive design research approach was employed through field observations, interviews, documentation, and literature review. Data were analyzed using qualitative, quantitative, spatial, and comparative approaches to identify spatial requirements and evaluate alternative design solutions. The analysis identified key deficiencies in the existing interior, including inefficient spatial organization, suboptimal relationships between functional spaces, limited workspace flexibility, inadequate integration of natural lighting, and the absence of a coherent visual identity reflecting the faculty’s sustainability-oriented character. The proposed design addresses these issues through functional zoning and circulation reorganization, optimized workspace configurations, flexible and ergonomic furniture, improved natural lighting integration, environmentally responsible material selection, and a consistent sustainable design language. The design process incorporates interior design principles, green building concepts, UI GreenMetric indicators, and Indonesian Green Building standards. The resulting design establishes a more systematic spatial arrangement and strengthens the functional, environmental, and visual relationships among workspaces. The study contributes a context-specific approach to optimizing academic and administrative interior spaces in higher education buildings and provides a practical reference for supporting green campus development in tropical environments.]]>
