Located a few metres from the Garden of Príncipe Real in Lisbon, this 41 m² plot allows the construction of a small 5-storey urban house for a family. The exiguity of the plot has led to a scheme where each floor has a different function and layout and all floors connect through a vertical atrium of variable geometry, providing a naturally-lit cadenced, progressive route. In addition to its spatial qualities, the atrium works as a thermal chimney for passive cooling during spring and summer and allows air renewal throughout the year.

Hard as it would be to plan a typical construction site in such a small plot, a light steel construction system – LSF – was used, which has an excellent thermal and acoustic performance. It is the first building in Lisbon made with this system.