This apartment in a two-story house from the 1920s in the center of Madrid belongs to the architect Marta Rodriguez y Arino. Its interior meets two requirements: to be as bright as possible and to include the architectural office area. The house had to be thoroughly repaired and was seriously changed during that time. The basement has been deepened and an additional lower level for the office has appeared. The floor of the terrace on the first floor had become transparent because thick glass had been used. This floor is also the basement ceiling, so that the office is always filled with daylight during the day. The private areas of the apartment are on the second floor, so that professional and private life are separated. The entire interior reflects the author’s worldview; The house is bright, clear and almost ephemeral.