‘A lot of floor spaces as much as possible ’that was a strong demand from the client was treated as ‘the loft space of the ceiling height 1.4m (child’s room)’.Because that space might not be counted in to the total floor area calculation as an architectural regulation in Japan. This is my speculation that it wants to give not only an area calculation meaning but also a spatial ability to the loft space that tends usually to be treated as ‘the secondary one’. The loft was made to be hung in midair in between the 1st floor and the 2nd floor. And it works as an engine that makes the air of this building unique. The loft prepares openings along the outside wall of this building which induce sunlight, ventilation and scenery on the outside. At the same time ’Ceiling of the aluminum specular finish’ weakens the power of ’Senses of depth’ and ’Outline feeling’ of the loft space by reflecting each other of real space and fictional space. The measurement of outline in the loft must become difficult. Reflecting real space and fictional space each other by the aluminum specular finish reduces the feeling of existence as the matter. But to the extent that it loses, on the other hand it van give the power to the part of its void (=air). The scene of the light poured from the basin and the void of the second floor will lend power so that the work of the loft may come to go well. The loft space as ‘the secondary one’ works as a concealed device that controls. It is like TOKONO-MA (the void space in Japanese tatami room) of vertical space.