Rooftop gardens Zandkasteel

Transformation of former ING headquarters

The former headquarters of the ING bank office in Amsterdam Southeast will be redeveloped into a school, offices, restaurants and social amenities. The Zandkasteel is a ‘Gesamtkunstwerk’ were architecture, material, color, art and gardens are designed as one intertwined organism. This makes the transformation a challenging assignment, which asked for a diligent design with the following guidelines: 1. Transformation from gardens to be looked at into gardens to be used. 2. Time changes DNA remains. 3. Greening on different levels, for healthy ways of living and a rich, urban ecology.

Client: Zandkasteel - Wonam
Date: 23 December 2021
Collaboration partners: LOLA Landscape Architects
Project type: design vision

Visualisation of new accessible rooftop garden

Japanese garden waterfall
(Picture: Copijn Bruine Beuk)

Japanese garden detail planting
(Picture: Copijn Bruine Beuk)

The exterior of ‘Zandkasteel’
(Picture: Alberts & Van Huut)

The interior of ‘Zandkasteel’
(Picture: Alberts & Van Huut)

Pictures of  ‘Zandkasteel’ and gardens in the time of the former ING head quarters. Build in organic style by Alberts & van Huut (Architects) and Copijn (landscape architects).


“Time changes, DNA remains” is the leading slogan for the transformation of the building. This principle will also be applied to the transformation of the existing, weathered rooftop gardens. Next to this new green spaces are added on the roofs of seven towers. The lush, green character, the biodiversity, the water and rocks are elements from the original design that have defined the canvas for both the old and the new greenery. Next to this additional functions and program will be added so the future inhabitants will be able to enjoy the outdoor rooftop spaces.

Transformation of existing rooftop gardens 

New, climate resilient rooftop gardens

Design concept: Sandy gardens on multiple layers

1. Existing gardens

2. Existing courtyards

3. New gardens

4. Adjacent greenery

5. Green facades

6. Art and objects

Sand Gardens

With ‘sandy gardens’ a thin, new landscape layer will be added to the Zandkasteel. These roofs can carry a limited amount of soil, but will still be able to get a green, urban character.

Sandy soil is poor in nutrients, which provides good circumstances for a specific ecology. The urban ecology is shifting due to climate change. There are species of flora and fauna that can adapt pretty well to more drought and heat. This type of ecosystem is applied to the ‘sand gardens’.

Sand comes in different kinds and grain sizes. This is used as a design element. The rooftop gardens on zeven towers will get a different mix of sand and small rocks, which will generate a large diversity in experience and ecology.

Plan drawing of new ‘sandy gardens’ 

Design elements out of fine grained, white sand

Design elements out of medium grained, orange sand

Design elements out of coarse grained, dark sand

Entrance square as dispensary

Next to the rooftop design the project will also be closely connected to the urban surroundings, with a special contribution to the neighbourhood. For this we propose a temporary garden installation. Small pieces of the unique sand-garden environment will be placed on the main square in front of the building, to afterwards be handed out to the local inhabitants. In this way the new Zandkasteel will provides a place for gathering and sharing, and simultaneously ecology can spread through the area.

1. Rooftop garden reproduction

2. Sand garden installation on entrance square

3. Give away buckets for local inhabitants.

4. Sandcastle as a ‘seed bomb’ for the neighbourhood.