For the first time in history, cities are home to more than half of the world population. Urbanization is increasing at a dizzying pace, and Amsterdam is no exception. The city aims to increase its urban density in formerly suburban areas – while simultaneously pursuing ambitious environmental goals.
This is the background to our Crossroads development. In a relatively ‘empty’ area of Sloterdijk, to the west of Amsterdam’s old city centre, Crossroads is a pioneering project. It makes a strong architectural statement while increasing population density in an underused urban landscape and also creating space for nature and for optimum sustainability.
Our building’s location is adjacent to Hemboog Station, with its raised track covered by an arched canopy. This feature, which defines the whole location, was the basis for our design. Our entire building folds itself around Hemboog Station’s curving canopy, integrating it into our design and creating a dynamic composition of geometrical forms.
Our towers flank the Hemboog’s semi-cyclindrical volume, creating a lively interplay between curved, rectilinear and triangular forms. The towers naturally draw the eye, making Crossroads a prominent and recognizable landmark. They also respond in height to the (planned) buildings around them and so fit in perfectly with their environment. Architecturally, Crossroads sets the tone for the further developments that will follow.
Crossroads creates two residential buildings with a clear substructure and defined boundaries between private (residential) and public (non-residential) programs. A lively living environment is realized, with facilities that open the building to its surroundings. The key design drivers are spatial quality and ensuring social safety.
The building consists of stacked volumes divided into a substructure, mid-construction and superstructure, with one high and one low tower. The substructure, the plinth, serves as a base beneath the other masses. The mid-height construction acts as an intermediary between the plinth and the high tower. The two towers each have their own identity and a distinct architectural style. The intermediate structure is different again, having a freer design.
At 90m high, the taller tower is residential. Slender and rectangular, its corners are made entirely from glass, and this open treatment ensures maximum views. The faceted façade creates a playful image thanks to the way the daylight falls on it.
On the Radarweg, the mid construction is segmented to break up its mass. Here the building folds back on itself twice, which creates maximum noise reduction. In addition, there are vertical setbacks with space for greenery and terraces.
The smaller tower is 40-m high and is designed to provide student housing. It has a modular aluminum and brickwork façade. It features a dynamic construction with generous, staggered balconies that give the building great architectural interest. These spacious balconies are fitted with large-scale, storey-high artworks placed against the façades of the building. They also offer space for greenery over the entire frontage.
All the facilities are concentrated at the entrance, which is located on the station side. Commercial spaces realized on the Radarweg include a bakery, a greengrocer, a bookstore and (potentially) a supermarket, adding vitality to the entire site.
Planting alongside Crossroads grows upwards to enfold the railway bridge that runs through the plan, creating the what we call the Green Hug, while rainwater flows down along the terraces, collecting in a basin. The space underneath Hemboog Station’s railway bridge has a special function as the Secret Garden. This garden connects the two residential areas between the towers.
The increasing amount and frequency of rain in Amsterdam has led to the city defining ‘rainproof’ standards for new buildings. Crossroads complies with and exceeds these. All the roof surfaces are equipped with the so-called polder roof technology of De Dakdokters. Solar panels are combined with water buffering in the form of crates that collect and retain rainwater.
Under the railway bridge, extra water storage will be realized in the form of a pond. This means Crossroads doubles the current 60-mm rainproof requirement of Amsterdam’ city council, boosting sustainability. In addition to the pond, the water storage also provides irrigation for the roof gardens.
The Secret Garden is a mysterious place under the railway bridge an on the roof of the plinth. Here, people and nature meet. In the industrial landscape, between intersecting roads, the garden is a wonderful surprise.
A pond with lilies is edged by green terraces that are connected by a walkway over the water. In the pond, moss-covered lava rock, a mist sprayer and subtle lighting create a magical atmosphere – a real fairytale experience. Light art, artistic lighting and a romantic decking terrace create a place to escape urban stresses underneath the railway bridge.
A more environmentally friendly city is also one of Crossroads’ goals, which it achieves with its polder roofs, green terraces and green façades.
The Green Hug combines an innovative roof landscape for water management and a green landscape for climate control. The focus here is on greenery and a habitat for small creatures. Greenery tempers the heat that lingers in the building and collects excess water. Substantial vegetation flourishes on all the roof terraces, except the tower rooftops which have solar panels instead. Greenery offers natural sun protection in summer, dampens noise, improves air quality, captures particulate matter and ensures pleasant humidity levels.
It also looks wonderful. From the ground level, climbing plants grow up against the façades, where they meet the vegetation of the roof terraces (the Green Hug). At the same time, water trickles down. The rainwater is collected on all the polder rooftops and is led downwards to the greenery and finally to the Secret Garden.
The City of Amsterdam uses energy efficiency requirements that are far above the national standard. As a result, Crossroads’ energy performance coefficient (EPC) is 0.15, thanks to its thermal exchange system, solar panels, smart installations and excellent insulation.
Crossroads is designed to be nature-inclusive (a place for plants and small creatures, as well as people), as well as climate-adaptive and rainproof, offering an unprecedented quality of life within the urban fabric. Through its unique biotope, it helps to green Sloterdijk. Where railways, motorways, cycle routes and walkways intersect and people streams meet, Crossroads becomes the stepping stone for flora and fauna between the Bretten zone and the Westerpark