Concrete cubes cascade down a Lisbon school in António Costa Lima Arquitectos' latest extension

A stack of shifting concrete cubes now hangs above the playground of the Colégio de Santa Maria in Lisbon, the work of Portuguese practice António Costa Lima Arquitectos. The extension replaces an illegal annexe that had been bolted onto the historic school building and adds new classrooms, laboratories, and a chapel to the campus.

The studio was commissioned by the Colégio de Santa Maria — the school itself, which owns the building — to rationalise the existing structure, improve accessibility, and add new teaching and recreational spaces. The original building dates to the early 20th century, when it was designed for a Catholic religious congregation. (Dezeen)

The illegal annexe that sat alongside the historic block has been demolished. In its place, the studio built what it describes as a ground-up reinforced concrete sculptural volume, running from the foundations to the roof. The cubes shift side to side as they rise, cascading down towards a terrace and playground below.

The studio says the form was informed by a promontory — a section of rocky, eroded land that juts out over the sea. The result is a building that reads less as a conventional classroom block and more as a landform, its cubic masses stepping and offsetting as they climb.

A new circulation core and lift make the historic building fully accessible for the first time, connecting old and new structures. The extension also adds laboratories and classrooms to the school's programme.

At the top of the stack sits a chapel that cantilevers slightly outwards. Its interior is carved from wood in a cubic form, and a section of glass floor looks straight down to a new playing court below. That glass panel creates a visual connection, in the studio's words, between the tabernacle and the recreation area — the sacred and the everyday, linked through a pane of glass.

António Costa Lima Arquitectos is a multidisciplinary practice working across residential, educational, corporate, and industrial architecture (Designboom). The studio lists the Colégio de Santa Maria project among its selected works on its official website (antoniocostalima.com). Previous projects include the conversion of a ruined tannery into the Montisnava Residential Building, completed in 2025 (ArchDaily), and a residential building by an aqueduct in Lisbon that involved demolishing a warehouse and constructing a new structure, completed in 2019 (ArchDaily).

What sets the Colégio de Santa Maria extension apart is the way it treats the gap between heritage and addition. Rather than mimicking the early-20th-century building or retreating into a glass-and-steel contrast, the studio chose raw concrete shaped like a coastal landform — a material and a metaphor drawn from the Portuguese landscape. The chapel's glass floor, linking a place of worship to a children's play court, is the kind of detail that makes the project feel designed from the inside out rather than imposed from above.

Dezeen published its report on the project on 20 August 2026.