Plan:b arquitectos Rounds Off a Planted Housing Tower and Gives Its Steep Medellín Slope a Public Stair

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This article covers topics related to Architecture, Curvilinear Architecture, Building Planning & Design, Architecture Project, Architectural Promenade, Building Design. In Medellín's Provenza neighborhood, 23 Living pairs curved, planted concrete balconies with a stepped public path that cuts across its sloping block.

In Medellín's Provenza neighborhood, 23 Living pairs curved, planted concrete balconies with a stepped public path that cuts across its sloping block.

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Plan:b arquitectos, the Medellín practice led by Felipe Mesa and Federico Mesa, completed 23 Living in 2019. The 6,400 m² residential building for developer Acrecer sits in Provenza, a neighborhood on the city's eastern hillside where the street grid bends and breaks to follow the terrain. The plot is long and drops steeply, the kind of site that usually produces a sealed podium of parking with a tower stacked on top.

Two moves make this project worth your attention. The first is formal: the slab edges are rounded and planted, so the tower reads from a distance as a soft column of green rather than a hard-edged block. The second is civic and easy to miss in photographs: a stepped public path runs along the southern side of the building, crosses the block, and shortens the walk for anyone moving through the neighborhood. A private housing developer handed part of its site back to the street, and we think that gesture deserves as much discussion as the curves.

A Tower That Reads Through the Canopy

Aerial view of a tower with planted curved balconies among treetops and high-rises, with green hills behind under scattered clouds

Tower with planted curved balconies rising above a canopy of leafy trees, a brick building beside it under a cloudy sky

Aerial view of the concrete-framed apartment block with planted terraces, rising above dense tree canopy under towering cumulus clouds

The aerial views show how much the building depends on its setting. Provenza is dense with mature trees, and the tower rises from that canopy with planters on every floor, extending the green vertically instead of cutting it off at the roofline. Against the hard, flat-faced high-rises around it, the effect is deliberate contrast.

The brick neighbor in image 5 is a useful reference. It shows the default for the area: a solid, gridded mass. 23 Living keeps a similar footprint and height but trades the wall for a layered edge of slab, column, glass and foliage.

Rounded Slabs and Slender Columns

Street-level view of the rounded concrete tower with stacked balconies trailing plants against a deep blue sky

Two stepped towers with planted balconies and curved slab edges, seen above treetops against a blue sky and hillside

Distant view of the upper floors with rounded concrete slabs and slender columns, framed by green foliage and wispy clouds

From street level the tower reads as a stack of horizontal concrete trays with rounded ends, held at the perimeter by slender round columns. The curves are not decoration added to a box. They come from the slab itself, and because the slabs project into balconies, each floor has its own visible line against the sky.

The concrete is left exposed, and the plants do the softening. Over time the trailing vegetation should blur the floor lines further, which suggests the architects designed the building to look its best several years after handover, not on opening day.

A Public Stair Through the Block

Stepped stone stairway beside a concrete facade of round columns and balconies trailing plants, under a blue sky with clouds

Dark stone stairway with wooden stools between curved concrete balconies and ferns, lit by dappled sunlight

Base of the tower with rounded concrete columns above dark stone steps, dappled in afternoon sunlight and shade

The stepped path on the southern edge is the project's most generous decision. On a steep hillside, a block-long detour on foot is a real cost, and this stair removes it. Dark stone treads climb alongside the building's columns and lower balconies, with ferns and wooden stools turning parts of the route into places to stop rather than only to pass.

Perforated brick wall beside a rounded concrete column and dark stone steps, with leaf shadows falling across the surface in low sun

Three rounded concrete columns standing side by side in front of a lattice brick wall and dark tiled steps

At the base, rounded concrete columns stand in front of a perforated brick lattice. The brick lets light and air through while screening what sits behind, and in low sun the leaf shadows across both surfaces make the ground floor feel shaded and cool. It is a modest material palette, but it gives the public edge texture and keeps it from feeling like the back of a car park.

Balconies Used as Rooms

Curved balcony with two wooden folding chairs beside a dining area, exposed concrete beams overhead and city towers in the distance

Curved concrete balcony with two timber lounge chairs and black stools, overlooking apartment towers and green hills under cloudy daylight

The curved balconies are deep enough to hold chairs, stools and a dining table close by, so they act as rooms rather than ledges. Exposed concrete beams overhead frame views toward the city's towers and the green hills beyond. In Medellín's mild climate, that outdoor space can stay in use for much of the year, and the plan seems to count on it.

Interiors in Walnut, Leather and Green Stone

Living room with green leather sofa, tan leather armchairs, stone coffee table and shelves lit beneath a timber-clad wall

Lounge with green velvet sectional sofas, cluster of faceted ceiling lights and wood-panelled ceiling, floor-to-ceiling windows facing city towers

Kitchen island with green stone countertop on a rough-hewn stone base, walnut cabinetry behind and a dried-flower vase on the table

Estudio Liberal, credited with art direction, concept and interior design, sets a warm counterpoint to the raw shell. Timber-clad walls, wood-panelled ceilings, green velvet and leather upholstery, and a kitchen island with a green stone top on a rough-hewn stone base all push the apartments toward a tactile, slightly retro richness.

The green palette is not accidental. It picks up the planters outside the glass and keeps the interiors visually tied to the facade. The floor-to-ceiling windows in the lounge make that relationship explicit.

Private Rooms Open to the Edge

Bedroom with walnut ceiling panels, a block wall holding a television and timber shelves, and sheer curtains open to a balcony

Bedroom with walnut paneled wall, botanical print above the bed and a tiled round column beside a balcony door in afternoon sun

The bedrooms continue the walnut panelling and open directly onto balconies through sheer curtains. In image 12 a tiled round column sits inside the room beside the balcony door, a reminder that the perimeter structure is part of daily life here, not hidden behind finishes. That honesty about where the building stands up is one of the better qualities of the interiors.

Plans and Drawings

Floor plan drawing of the lowest basement level, a rectangular slab ringed by circular columns around a central core with stairs and lifts

Floor plan drawing of the fourth basement level showing a curved ramp wall at the west end and service rooms beside the core

Floor plan drawing of the third lower level showing the column-ringed volume, a bathroom block and a planted path with trees beside it

The lower plans show how the slope is absorbed. The deepest levels are rectangular slabs ringed by circular columns around a central core, with a curved ramp wall at the west end. As the levels rise, a planted path with trees appears beside the volume, the first sign of the public stair.

Floor plan drawing of the second lower level with a curved glazed volume, a central core and a terrace with café tables above

Floor plan drawing of the first lower level showing a narrow, rounded-end wing with rooms, a core and a tree-lined paved edge

Floor plan drawing of the upper level showing a long narrow wing with rounded west end, a central core and a row of trees on the east side

Near grade, the building narrows into a rounded-end wing with a curved glazed volume and a terrace with café tables above. A row of trees lines the paved edge, which suggests the ground levels were designed to meet the path rather than turn their back on it.

Floor plan drawing for levels 2 and 3 showing four apartments around a central core with stair and lifts

Floor plan drawing for level 4 showing a rounded rectangular slab with apartments flanking a central stair core

Floor plan drawing for level 5 showing apartment layouts, bedrooms and living areas arranged around a central circulation core

Floor plan drawing for level 6 showing paired apartments with curved wall edges on either side of the core

Floor plan drawing for levels 7 and 8 showing the repeated apartment arrangement within the rounded slab outline

Floor plan drawing for level 9 showing an open full-length living space with a kitchen island and two end bedrooms

The typical floors organize apartments around a single stair and lift core within the rounded slab outline. Layouts shift from four units on levels 2 and 3 to paired apartments with curved wall edges, and level 9 opens into a full-length living space with a kitchen island and bedrooms at each end. The core stays fixed while the unit mix changes, which is an efficient way to offer variety within one tower.

Tenth floor plan drawing of a long rounded rectangle with a service core, columns and planters along the perimeter

Roof plan drawing of an elongated rounded slab showing round tables, a skylit strip and a row of bays

Building section drawing through a tall slender tower above a sloped site, with cars parked in three basement levels

Building section drawing cut through the tower floors and stacked basement levels, with the ground line sloping across the site

Building section drawing showing a tall central wall running from the rooftop down through the basement parking levels

Building section drawing of the tower with repeated floor plates, planters on each edge and a stepped basement beside a neighbouring structure

Building section drawing cutting through a tall residential tower, showing stacked floor slabs, a central stair void and two basement parking levels below grade

Building section drawing showing a central core with a diagonal stair run, flanking floor plates and underground parking levels beneath a sloping site

South elevation drawing of the tower with curved balconies and window bays, cut away at the base to reveal terraced stepped levels and parking floors

The sections make the site's difficulty legible. A slender tower sits above stacked basement parking, with the ground line sloping hard across the cut. Planters appear on each floor edge, and the south elevation is cut away at the base to show the terraced stepped levels where the public stair climbs. The roof plan, with round tables and a skylit strip, indicates a shared top floor.

North elevation drawing showing a gridded facade of windows and perforated screen panels above a sectioned basement with stepped terrain on either side

West elevation drawing of the slender tower with rounded balcony edges, a faint neighboring facade at left and a sectioned curved basement below

East elevation drawing of the narrow tower on a steeply sloping ground line, with a neighboring building outline to the right and dashed basement levels below

The elevations show a building with two faces. The south and west read as curved balconies and window bays, while the north is a gridded facade of windows and perforated screen panels. The east elevation is the clearest record of the terrain: a narrow tower standing on a steep ground line with neighbors pressed close on either side.

Why This Project Matters

Hillside cities usually treat steep plots as a parking problem with apartments on top. 23 Living treats the slope as a chance to repair the pedestrian network, giving the neighborhood a shortcut it did not have before. That is a small piece of urbanism, but it is the kind that adds up when developers in dense, irregular neighborhoods like Provenza choose to offer it.

The rounded, planted slabs will get the attention, and they earn it by making a mid-size housing tower feel lighter and more connected to the canopy around it. The more lasting lesson is the combination: an expressive residential envelope, interiors that match the green outside, and a public stair along the edge. Plan:b arquitectos shows that private housing can work for the street as well as for the people who live in it.

23 Living by Plan:b arquitectos (lead architects Felipe Mesa and Federico Mesa), with art direction, concept and interior design by Estudio Liberal. Medellín, Colombia. 6,400 m². Completed 2019. Photography by Alejandro Arango Escobar.

About the Studio

Plan:b arquitectos

Official website of Plan:b arquitectos, one of the studios behind this project.

planbarq.com

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