Copenhagen-based architecture studio EFFEKT has completed Harmonikahusene, a striking student housing complex in Frederiksberg, Denmark, featuring a distinctive red accordion-like facade that zigzags across two curved building blocks. The development, also known as The Accordion Houses, provides 519 student apartments and 158 additional units for young professionals, along with extensive communal facilities for both residents and the local community.
The complex consists of two interconnected curved structures named Umeus and Noli, connected by a glazed reception area at ground level. The buildings are approached via wide brick steps and feature planted courtyards that serve as focal points for the development. EFFEKT designed the project for developer Nrep, creating a contemporary interpretation of traditional Danish residential architecture.
The most striking feature of Harmonikahusene is its accordion-style facade, composed of zigzagging bay windows that create a dynamic visual rhythm across the building's exterior. EFFEKT co-founder Tue Hesselberg Foged explained that the angle of these bay windows gradually steepens toward the north, creating an "unfolding" effect that ensures eastern and western light reaches even the northernmost apartments. Each bay window is equipped with a large built-in bench and specialized grilles that facilitate natural ventilation while minimizing noise from the adjacent road.
The color scheme pays homage to Frederiksberg's architectural heritage, with EFFEKT translating the area's traditional red brick buildings into a contemporary palette using custom-designed red glazed ceramic tiles and colored aluminum. "We translated the traditional red brick of Frederiksberg into custom-designed red glazed ceramic tiles, creating a lightweight facade that allows the bay windows to function successfully," Foged told Dezeen. "It's a contemporary reinterpretation of the grand historic buildings along Åboulevard, making the architecture feel tactile, generous, and grounded."
The building's organic curved form serves both aesthetic and practical purposes, avoiding the shadowed corners created by traditional 90-degree angles while adapting to its urban surroundings. On one side, the structure follows the existing urban fabric and is set back from the busy road to create a generous planted buffer zone. On the opposite side, it steps down in height to form smaller point houses that open toward the courtyard and accommodate small retail spaces.
Inside, the complex offers a diverse mix of accommodation options, including single, couple, twin, and studio units. Most apartments are organized around communal kitchen areas, fostering a sense of community among residents. The units either overlook the central courtyards or face the road to the north, with the bay windows providing additional living space and natural light.
The ground floor features an extensive range of shared amenities including a library, laundry facilities, study areas, and fitness spaces. Additionally, the development includes planted rooftop terraces that offer panoramic views over the city. At the base of the smaller cubic volume, residents and locals can access a cafe, bike shop, and grocery store, creating a vibrant street-level presence.
Foged emphasized the project's contextual sensitivity, noting that despite adding a significant number of homes and increasing Frederiksberg's population by almost one percent, every design gesture was carefully calibrated to its surroundings. The narrow ends of each U-shaped block help break down the development's scale when viewed from the quieter street to the south, while the glazed ground floor creates transparency and connection with the neighborhood.
EFFEKT, founded in 2007 by Foged alongside Sinus Lynge, has previously completed notable projects including an electric vehicle charging station in Sønderborg and an accessible treetop walkway. The Harmonikahusene project represents the studio's continued commitment to creating architecture that responds thoughtfully to local context while addressing contemporary urban housing needs.
