Spherical House in São Paulo Opens for ABERTO5 Exhibition

Rare Public Access to Experimental Brazilian Architecture

A radical spherical house in São Paulo will open to the public for the first time from March 7 to May 31, 2026. The futuristic structure hosts the fifth edition of ABERTO, a Brazilian architecture and art exhibition platform. Casa Bola, built between 1974 and 1979, represents one of Brazil’s most experimental domestic spaces. The eight-meter-diameter sphere challenges conventional housing paradigms.

Hand-Built Prototype Defies Traditional Design

The architect constructed this spherical house entirely by hand using ferrocement. Moreover, he molded the material over a complex mesh of recycled steel tubes. The construction method integrates walls, furniture, lighting, and sanitary elements into one continuous organic form. Additionally, the dwelling sits suspended above a rooftop slab in the Itaim Bibi district. The project marked a significant departure from angular geometry toward spherical systems during the 1970s.

Rooftop terrace of the Spherical House featuring a yellow slide, circular windows, and organic architectural forms. — The residence features playful elements like a yellow slide and organic pathways that connect the dwelling to the rooftop terrace. (Image © Ruy Teixeira)

This experimental vocabulary contrasted sharply with the transparency and structural rationalism of Brazilian modernist architecture at that time. However, the spherical house remains inhabited by its creator and largely unknown within the urban landscape.

Exhibition Transforms Private Architecture Into Public Platform

ABERTO5 presents over 60 art and design pieces by 50 Brazilian and international artists across three floors. Furthermore, the exhibition spans 1,000 square meters including the terrace and spherical house. Many contemporary works respond directly to the radical character of this habitable sculpture. The curatorial framework positions the spherical house as a setting for artistic experimentation.

Close-up detail of the ferrocement facade and louvered windows of the Spherical House against a modern glass skyscraper. — The hand-molded ferrocement shell includes integrated louvered windows, contrasting sharply with the rationalist architecture of neighboring towers. (Image © Ruy Teixeira)

Platform Continues Modernist Architecture Series

This edition continues a significant pattern of activating historic private residences. The inaugural 2022 edition took place in the only private residence designed by Oscar Niemeyer in São Paulo. Subsequently, the 2023 edition featured a house by Vilanova Artigas. The 2024 edition opened two modernist homes to the public for the first time. Additionally, the 2025 edition marked the first international presentation at Le Corbusier’s Maison La Roche in Paris.

The platform reactivates buildings of historical significance by transforming them into settings for contemporary art and design dialogue.

Interior detail showing a rounded metal door and organic hand-molded wall textures covering infrastructure pipes. — The construction method integrates walls and infrastructure into a continuous organic form, visible in the molded piping details around the entry. (Image © Ruy Teixeira)

Will this spherical house inspire renewed interest in experimental housing prototypes from the radical architecture movement?

A Quick Architectural Snapshot

The spherical house measures eight meters in diameter and sits suspended above a rooftop in São Paulo’s Pinheiros subprefecture. Ferrocement molded over recycled steel tubes creates the continuous structural shell. The dwelling integrates all functional elements into its organic form. Construction occurred entirely by hand between 1974 and 1979, establishing a prototype for spherical housing systems.

✦ ArchUp Editorial Insight

A privately built dwelling remains invisible within a dense metropolitan fabric for nearly five decades. It surfaces publicly only when an exhibition platform requires a venue of sufficient symbolic capital. This sequence is not coincidental.

The pattern: experimental residential architecture in Latin America achieves visibility exclusively through cultural event cycles, not through institutional documentation, planning recognition, or pedagogical integration. The decision framework prioritizes curatorial access over archival permanence. Consequently, structures like this enter collective memory as exhibition backdrops rather than as construction knowledge.

The ferrocement-over-recycled-steel method represents a replicable low-cost system developed outside institutional research channels. Its non-adoption over five decades signals a procurement and insurance logic that cannot process handmade structural continuity. The sphere persists as prototype, never as precedent.

The recurring condition across all five editions follows one rule: private modernist residences become publicly legible only when art markets activate them.