So the designers built a cor-ten spiral staircase next to the existing block building.

Disturbing the site as little as possible was important to the architects so they worked around the topography as much as they could. And they chose shapes and materials that emphasized the aesthetic quality of the existing building. For example, the rusted steel staircase contrasts dramatically with the light-colored stone in the same way that the spiral form contrasts with the original block tower.

Making the additions fit in so seamlessly with the original design could not have been a simple task, but Castillo and Miras have managed to mesh the old and new as though they had always been that way. This beautiful lookout tower embodies the most humble form of sustainable renovation.

+ Castillo Miras Arquitecturos

Via Dezeen