Prefabricated construction method offers solution

Puzzling on an Amsterdam postage stamp

With Fibonacci, diederendirrix designed 243 sustainable rental apartments for the scarce affordable segment in Amsterdam. 20% will be social rental and 80% is intended for the middle segment. For the plot, reminiscent of a triple pie slice, she created a striking urban design that looks different on all sides due to the subtle rotation of the three volumes.

Back in 2015, diederendirrix created the first design for Fibonacci. Back then, the firm already drew the dwellings around a soundproof atrium, introduced the stepped form and created a large building that, despite its substantial dimensions, did not appear to be dominant anywhere. But the challenging boundary conditions played tricks. The size, shape and location of the plot, the small building site and the claims regarding noise and safety were difficult to combine with the demand for affordable rental housing. Together with client VORM 2050, the idea then arose to realize the homes with an innovative, prefabricated construction system. This was the key to making Fibonacci feasible. 

Prefabricated construction method

Developer Vorm 2050 invited all executing parties at an early stage to discuss the prefabricated construction method. "Because of this early involvement, knowledge and know-how was shared in many areas," says Niels Ponjee, architect at diederendirrix. "It turned out that entire building components could be delivered completely prefabricated: interior walls, floors and precast concrete facades, complete with window frames, glass, insulation and stone strips. Even the bathrooms and technical rooms could be delivered as ready-to-use units. On site, these could then be assembled like a kit. This would reduce construction time as well as site inconveniences."

Fast progress, smart decisions

Corona helped shape the plans. Whereas it is normally a neck-and-neck affair to get five people together, a Teams meeting with 20 people at Corona time proved no problem. As a result, progress was made quickly. The facade was given a stability function, allowing the concrete shell to remain relatively light. Large concrete cores to keep the building upright became unnecessary. With wall finishes in the galleries made of Cross Laminated Timber, the atrium became an interior wooden world, covered with glass covers. "It feels like outdoors in there, but it's dry."

Step by step feasible

The busy city was shut out. Instead of balconies on the outside, large roof gardens with trees and shrubs were created on the roofs. The tallest tower was given a roof with Windwokkels for sustainable energy generation. Birds and insects were also considered. For them, nesting boxes and insect hotels were incorporated into the facades and garden design. This created a pleasant place for people and animals. And Fibonacci became feasible step by step. "Meanwhile, construction is in full swing," Ponjee concludes. "The homes will be purchased by housing foundation Stadgenoot and real estate developer Rockfield, who will rent the homes. Rockfield rents 194 homes in the middle segment and Stadgenoot rents 49 homes in the social segment. As architects, we have again contributed something to an important task in contemporary spatial planning. We love that urban densification in difficult places. That way even more people can find a place in the city."