The street Presidente Arriaga, located between Alcântara and Santos in Lisbon, is part of a dense urban fabric composed of blocks and irregular lots, adapted to the topography. The area is predominantly occupied by residential buildings, some of which include ground-floor commercial spaces. The objective of the intervention was to transform the building, originally structured with one apartment per floor, into a single-family residence. A technical inspection carried out in December 2022 confirmed that the original structure consisted of stone masonry walls (approximately 50 cm thick) and two central cross walls extending from the ground floor to the second floor. The third floor, a later addition, did not follow the same structural logic.
In accordance with regulatory requirements, the central cross-shaped structure and the typical staircase of pre-Pombaline buildings were preserved. To improve spatial amplitude, the slab in the rear-facing rooms—where ceiling height was reduced and non-compliant—was removed.
The existing staircase was reconfigured, maintaining its original typology up to the second floor. The ground floor now includes a garage and the main entrance. The first floor is designated as the social area (kitchen, dining, and living room), with direct access to the rear. The bedrooms are located on the upper floors.
Previously fully occupied, the rear area was transformed into a garden/patio that connects directly to the living room, which features a double-height ceiling.