This project integrates into one building the three aging administration and welfare buildings that formerly occupied a corner of the factory site. Demolition of the old structures created an expansive front courtyard and a space behind the new building for future extension. The robust, low-cost, low-rise office building is a mixed structure of reinforced concrete pillars with earthquake-resistant walls and steel beams. The main façade, comprising a pillar-and-beam frame and molded cement slab, greatly contributes to energy efficiency through a louver effect. Matching the rhythm created by the frame, granite recycled from the old Kajima head office forms a striped pattern in the front courtyard, thus providing a record of the old headquarters. The frame is visible internally and externally, while the building’s restrained height provides an efficient core, making it a prototype for a low-cost, low-rise office.