In recent years, subareas of the Kop van Zuid area of Rotterdam have been redeveloped, transforming them from industrial docklands into a lively urban centre. These subareas have been worked out from an urban development viewpoint on the basis of a Master Plan developed by Riek Bakker and Teun Koolhaas. The Ichtushof project is the latest building location to be tackled in the Zuidkade II subarea. The urban development plan for this area has been drawn up by architects Van den Oever, Zaaijer & Partners in close cooperation with EEA Architecten. The Hogeschool INHolland college, designed by EEA Architecten, makes up part of the Ichtushof. One of the office buildings to be further worked out opposite this educational building was designed by architects Van den Oever, Zaaijer & Partners. This is a ‘multi-purpose’ office building on the Laan op Zuid, with a gross floor area of 27,000 m2. The building, the highest section of which is an 18-storey tower, is being developed jointly by OVG Projectontwikkeling and AM Vastgoed. The complexity of the assignment granted to architects Van den Oever, Zaaijer & Partners lies in the extremely narrow building plot, which permits only a very limited footprint. The reason for the plot being so narrow is the space to be reserved for the existing and planned metro route. Without specific interventions in the design, this footprint would be too small for the realisation of the required volume within the boundary conditions set. Allowing sections of the building to protrude extensively from the first floor outside of the footprint, made it possible to achieve the desired volume. Inclined trestles lift the highest section of the building from the footprint, high above ground level. From the fifth floor, the structural bays project 9 m over the metro route, in relation to the column base.

Unique character of each section Thanks to its mass form, divided into sections with three volumes, its dimensions and the possibilities for linkage, the building is suitable to accommodate several users. Building depths of 14.40m and 22m make a wide variety possible, from smaller office types to large, open-plan offices with an efficient, modern office layout. Although the building, with its robust brick look, comes over as a single entity, each volume within it has its own, recognisable details. In spite of the large, flexible lettable floor area, the building does not make an anonymous impression, but rather each section has its own character, allowing different users to present themselves with their own section of the building. The highest section, for example, literally towers above the other sections. The tower is characterised by vertical brick ribs that pass in front of the glass exterior wall. Above the roof, these ribs terminate in a white crown, which lights up brightly in the sunlight. The next highest building section has vertical window openings, which are linked every two storeys and are deeply recessed in the exterior wall. The openings are interrupted horizontally by a brickwork area made from special toothed bricks, known as ‘bishop’s caps’. This creates a sophisticated ornamental breast that is an integral part of the facade. Vertically, the window frame openings are divided into two panels by a clear white rib. The low building section has window frames that are contrastingly placed as far forward in the surface of the exterior wall that these protrude from the facade. Although the design of the exterior walls differs between the various building sections, the use of materials and ornamentation are visibly related. The bonds and ribs in red hand-formed bricks were inspired by the ornamentation used in traditional Dutch brickwork, but also clearly have a contemporary look. Together with the composition and varied contours of the mass, the high degree of plasticity of the exterior walls gives the building as a whole an unmistakeably urban character. To give a sense of human scale from ground level, a ‘second contour’ has been introduced alongside the overhang, placing the large scale of the building in context. This contour is formed by the shadow effect of profiled ribs in front of the brickwork of the lower sections of the exterior walls. On the ground floor of the central section, a double-height, transparent space that can be laid out as required is planned, making use of the entire building plot. This gives the building a public, transparent plinth course and corbelling on the street side. This large space will act as a ‘market square’ for main lessee UWV, which is using some three-quarters of the building (17,000 m2). The remainder (10,000 m2) is leased by the Tax and Customs Authorities. The plinth course is clearly distinct from the superstructure and is built in glass and natural stone. There is a split-level underground car park with five levels and space for 287 cars.

Sustainable office building Sustainability was one of the major preconditions for the design as specified by the client. With all of the measures included in the design, the office building – with an environmental index of 206 points – is one of the most sustainable buildings in the Netherlands at this moment. This classification is based on the GreenCalc rule applied by the Government Buildings Agency. Firstly, the building design is extremely compact, which leads to energy savings. Passive energy saving arises through the use of narrow, high window frames, which allow daylight to penetrate far into the space. Automatic daylight regulation and presence detection systems ensure further saving of electricity for artificial light. For energy efficient climate control, use is made of underground heat/cold storage. Sustainable, maintenance-friendly materials have been used as a matter of course, and future sustainability has also been taken into account. The exterior walls consist of loadbearing prefab elements which, at the end of the building’s life, can be disassembled and re-used.