Houtrak Apartments: Sustainable Prefabricated Living on Oostenburg Island, Amsterdam

Houtrak Apartments, designed by Marcel Lok Architect and Workshop Architecten, exemplifies contemporary residential architecture on Amsterdam’s Oostenburg Island. Completed in 2025, the 3,339 m² complex is strategically positioned at the end of the Oostenburgervaart, within a revitalized former industrial area. This urban district now thrives with a mix of residential and commercial spaces, including cafes, shops, and a hotel, anchored by the monumental Van Gendt Hallen and the INIT-building.

The Houtrak project consists of two distinct buildings. The first is a six-story block featuring recycled Azobé wooden facades and solid wooden balconies overlooking the water. The second is a four-story structure with shed roofs and black-brown metal facade cladding, oriented towards Isaac Titsingkade and Rumphiusstraat. Together, they balance industrial heritage with modern sustainable design.

A key innovation in Houtrak Apartments is its fully prefabricated modular construction. Utilizing the CD20 modular system, prefabricated concrete floor slabs rest on massive wooden columns, creating an open structural framework. Light partition walls fill this structure, while all installations are separated from the load-bearing system, allowing future adaptability and layout flexibility. The solid Azobé wooden balconies reference the site’s industrial past while providing generous outdoor spaces for residents. This approach enables fast construction, durability, and flexible living options.

The complex houses 36 diverse apartments, ranging from compact 38m² studios to 160m² top-floor units. Every apartment features expansive balconies, 2.5 meters deep and spanning the full width of the unit. Roofs are also designed for private and communal roof terraces, with select apartments enjoying private spaces and a shared terrace atop the wooden building. Practical amenities include a semi-sunken communal bicycle shed, reflecting Amsterdam’s cycling culture.

Sustainability is at the core of Houtrak Apartments. Each unit is equipped with an individual heat pump, high insulation, and triple-glazed windows in wood-aluminium or wooden frames. The wooden facade panels are sourced from reclaimed side planks of Dutch canal retaining walls, while the metal cassettes are powder-coated in grey-brown, requiring minimal maintenance. Over time, the Azobé wood develops a weathered, natural patina, enhancing both aesthetics and longevity.

Both buildings feature entrances on Isaac Titsingkade, connected by a compact light court adjoining all front doors. Ground floors include split-level two-story houses with double-height living spaces, while upper floors offer a mix of lofts, studios, and large apartments. The wooden building’s cantilevered balconies extend over the water, while the metal building integrates semi-indoor balconies into the facade, ensuring privacy. Additionally, a collective rooftop garden, designed by Flux Landscape Architects, crowns the wooden building, providing residents with communal green space.

All photographs are works of Anna Odulinska