Brazilian architecture firm AT Arquitetura has completed a new headquarters building for the Unimed Federation in Porto Alegre, Brazil, showcasing innovative sustainable design principles and adaptive reuse strategies. The 3,800 square meter office complex, completed in 2025, represents a thoughtful approach to urban development that prioritizes environmental responsibility and community engagement.

The project stems from the fundamental principle that "the most sustainable building is the one that has already been built." Led by architect Tarso Carneiro, the design team including Mauricio Ceolin, André Detanico, Daniela Yumi Yoshimoto, Ruy Lunardi Neto, Natalia Luz, Dadja Lovato, and Guilherme Groth focused on adaptive reuse, expansion, and modernization of an existing structure rather than demolishing and starting from scratch.

A key feature of the development is its generous relationship with the surrounding urban fabric. Through the strategic acquisition of three adjacent lots, the architects created a new public square by setting the building back from the street. This design gesture serves as a thoughtful transition between the city and the building, demonstrating what the architects describe as "urban generosity" that benefits the broader community.

The architectural solution employs a sophisticated hybrid structural system that combines the existing framework of the original building with a new independent structural system. This approach creates a unified architectural element where preserved portions of the old structure engage in dialogue with contemporary components. The result is a building with hybrid character that respects the site's memory while providing the structural flexibility needed to meet modern workplace requirements.

The building's metallic façade plays a central role in its environmental performance. An envelope made of perforated panels and metal brise-soleils modulates natural light and provides essential shading, significantly minimizing unwanted heat gains. This sophisticated skin works in conjunction with passive comfort strategies including optimized solar orientation and cross ventilation throughout the work modules.

Inside, the open-plan layout accommodates diverse work environments designed for the modern workplace. The interior features silent focus areas for concentrated work, collaborative spaces for team projects, modular meeting rooms that can be reconfigured as needed, and informal social areas that encourage interaction among employees. The fluid design between zones allows for easy adaptation to changing operational needs, fostering a flexible, human-centered scale that prioritizes user comfort and productivity.

The layout maximizes natural light penetration and views throughout the workspace, creating visual connections between the building's interiors and the surrounding urban landscape. This design strategy not only reduces energy consumption but also enhances the well-being of occupants by maintaining their connection to the outside environment.

Capping the complex is a rooftop terrace that provides additional value to the building's users and the broader community. Positioned above the most active areas of the building, this open space functions as an extension of the building's interior life, offering a place for gathering, resting, and leisure activities. The terrace reinforces the connection between the building and its surrounding context while providing opportunities for contemplation and socialization.

The project involved collaboration with several specialized consultants to ensure optimal performance across all building systems. Diogo Valls handled the structural engineering, while Cristina Maluf Iluminação provided lighting consultation. Kucha Saatkamp designed the landscape elements, and Studio Bim managed structural design and installations. Additional expertise came from Studio T for approval and fire safety systems, Marcos Abreu for acoustics, and Studio MD for wayfinding systems.

The Unimed Federation headquarters represents a model for sustainable urban development that other cities and organizations can emulate. By prioritizing adaptive reuse over new construction, creating public amenities, and incorporating advanced environmental systems, the project demonstrates how architecture can serve both private clients and public interests simultaneously.