By relying on the main house for the large kitchen, bathroom, and future children’s room, only a few functions for a living space are required for the extended part. The living spaces are aggregated into a simple continuous structure, which consists of small, 2m high, U-shaped bearing walls. A V-beam roof truss is made with 62mm panels and structural plywood on both sides, and it is topped with a 69mm thin roof. By overlapping the bearing walls and the V-beam frame, and by using a variety of finishes, contrasting spaces are created and a sense of scale in the vertical direction is born in the flat house. By doing so, as the residents’ living scenes unfold, light and air freely circulate in the space, and the people’s lines-of-sight extend beyond the area in a state of freedom. We intended to leave a rich blank space that fosters the imaginations of the residents.