Tha Phra Office is a 655-square-meter three-story office renovation situated adjacent to an old factory compound along Khlong Bang Sakae, Bangkok. The project restructures the building to accommodate both departmental corporate workplaces and a private third-floor residential penthouse for the owner. Level 1 houses the primary reception, executive offices, conference room, pantry, staff canteen, and detached utility pavilions, with a private rear entrance and elevator lobby providing direct, dedicated access to the third floor to ensure complete domestic privacy. Level 2 accommodates open-plan offices and meeting rooms designed for future flexibility. Level 3 transforms into a full residential penthouse uniting living, dining, kitchen, laundry, and family bedrooms. On the exterior, a new facade integrates perforated metal screens and vertical concrete fins to provide rhythmic shading and contemporary unity. The interior preserves original terrazzo floors and raw concrete in the lower loft-style offices, while transitioning into warm timber millwork and terracotta brick accents in the private penthouse above.