Cet article, issu du hors-série A+278 Brussels, vous est proposé en anglais. En effet, les hors-séries sont édités uniquement en anglais.
Brussels is a compact city. In part, this is born of necessity: the city is wedged into a tight straitjacket between Flanders and the Ring road, its population is rising steadily, and the pressure on housing is already high. But its compact nature is also a deliberate policy choice: the decision to opt for a city of proximity, of lively quarters with a mixture of residential and commercial functions (including industry), and with access to green space and public services. The compact city is designed for pedestrians, with a sufficiently high density to allow public transport to function efficiently. It is important, however, that this compactness should take shape in a variety of ways, with a range of typologies, so that living in the city is also both feasible and attractive for a diverse audience, including families with children.
Density in Brussels does not always run according to a clear vision. The larger reconversion and densification projects are developed on parcels of land that are freed up when other functions cease to be operational. In the meantime, a creeping but harder-to-map densification is taking place through small-scale projects such as splitting or adding storeys to existing homes, merging terraced houses to create apartments, redeveloping warehouses into lofts, or supplementing urban blocks by constructing on still-undeveloped plots.
Taking into account demographic evolutions such as reduced family sizes, the population becoming both younger and older, and also the diversity of housing requirements, densification operations can deliver a fine example of high-quality and collective housing types. Moreover, densification goes hand in hand with a growing need for (public) open space and community infrastructure. Brussels residents do not generally have their own gardens, and increasingly make their voices heard when new development and densification projects are mooted. The existing classic (metropolitan) urban parks, which in the summer often resemble crowded beaches awash with Brussels residents in search of somewhere to cool down and relax, are supplemented by more diverse, smaller-scale and more ‘programmed’ open-space initiatives. The case for greater variation therefore applies to open spaces and to housing typologies in equal measure. To what extent does this diversity already play out on the ground, in the specific urban projects that are further densifying the capital?
A string of new densification projects in the Canal Zone
Today the Canal Zone forms a string of new, large-scale developments in what is already an incredibly dense environment, with its strikingly large proportion of small apartments in generally closed urban blocks, inhabited by a socio-economically vulnerable population. The extensive amount of hard surfacing tends to generate a high level of heat stress in the summer, and there is little accessible greenery to provide breathing space or an opportunity to cool down. And yet a large number of new densification projects continue to be concentrated in this Canal Zone where former industrial sites become available and existing buildings are obliged to make way for upscaling, driven by rising land prices. Along the waterfront, which is an attractive place to live, densification becomes more rational, affordable and profitable for project developers. Moreover, project developers are less likely to be confronted by outspoken individuals in the central Canal Zone who see their own dream homes threatened by densification and an increase in scale. The last remnants of open space and greenery are systematically gnawed at in successive phases of the plans – as demonstrated by the developments at Tour & Taxis. Despite the need for affordable homes for the existing population, including for larger families, developers systematically choose to build a one-sided offering, aimed at the upper middle classes and investors, of small one- and two-bedroomed apartments, a typology that delivers the highest profit per square metre. To assuage the most pressing need, in the densified Canal Zone we chiefly see scraps of leftover space, snippets of green or short-cuts transformed into small-scale parks tailored to the local area, such as the four pocket parks beside the L50 train tracks, or the Zennepark at Masui.
The mixed-use building: hyper-urbanity in the station quarter
Yet there are also a number of interesting examples of new quarters in the Canal Zone that integrate innovative architectural and urban-design concepts in their projects. The repurposing of the WTC I & II towers could serve as a catalyst to achieve the objective of once again making the Manhattan quarter around the North Station a lively, mixed and dense residential and commercial area, located beside one of the best-connected stations in Belgium. The architects – a consortium of 51N4E, l’AUC, and Jaspers-Eyers architects – will transform the monofunctional office block into a mixed-use building in which living and working alternate per floor like a millefeuille. With its lively and publicly accessible plinth, which will house both commercial functions and a greenhouse and sports facility, the WTC will become a section of the city on the scale of a building.
The productive urban block
Further to the south in this same Canal Zone we find Urbanities, one of the new projects in the quarter around the Biestebroeck Dock. It is currently an under-developed and less-accessible quarter, but this is all set to change in the coming years. The architectural concept for Urbanities, which MSA, Plusoffice and B2Ai will be designing, tackles the stacking of functions in an innovative way. Three aligned tower volumes are oriented towards the canal and are linked to the other, lower-rise residential buildings by means of a productive base that provides space for light industry. The integration of industry into the urban fabric is an explicit ambition of the Brussels-Capital Region: this can only be achieved via an entirely different construction typology. Here, it is essential to combine the different scales demanded by production and residential activities in a liveable way. On the roof of the base there is also space for a shared garden with urban agriculture and a greenhouse, and the ambition is to recuperate waste flows from the industrial activities (heat and CO2). The proximity principle of the compact city, with the combination of living and working, production and consumption, is applied here on the scale of an urban block.
Completing the urban fabric: sustainable and affordable
Further north along the canal, on the Tivoli site, we find a project that aims to create a mix of affordable homes for sale and social homes for rent. The new development, made up of five urban blocks that are being tackled by different design teams, is a textbook example of an ecologically and socially sustainable quarter: it is a high-density neighbourhood with a mixture of target groups and functions, but which also provides space for trade, crèches, collective (laundry) areas, vegetable patches, green roofs and a conservatory; all homes are passive and some are even energy-neutral, and grey water is recuperated. However, in terms of urban planning and architecture, the project is insufficiently daring. The ensemble of the five rather classical, closed urban blocks, with little difference in building height, fills up the existing urban fabric, and adds little new dynamism to the public domain. Through traffic is not permitted in the inner streets, admittedly, but there is a missed opportunity here to knit together the five urban blocks into a single superblock following Barcelona’s example. A total ban on motorized traffic would open up possibilities for creating a new type of public space, instead of the classic street or (semi-)private courtyard or garden.
Campus becomes a lively city quarter in a park-like setting
A number of larger urban-regeneration projects are also accumulating at sites beyond the Canal Zone. More widely dispersed across the city, they occupy the spaces that became available due to the disappearance of large-scale functions, or via a change in the way the area is organized. At several of these sites, the campus model is being exchanged for more mixed and urban typologies. The relocation of the Flemish and French-language radio and television broadcasters VRT and RTBF to the Reyers site prompted the development of a new city quarter in which residential dwellings are slotted into a park-like environment. The same trend is also visible in the renovation projects of larger ensembles, often social housing blocks, with new building volumes that create a different scale and expand the range of amenities. Dierendonckblancke architects added two residential volumes to a social housing project on Condorlaan in Molenbeek, but they also succeeded in activating the somewhat undefined green space between the buildings. This was orchestrated by inserting a smaller-scale collective pavilion as a link between the various residential properties. The fact that it’s not just the Canal Zone that is being considered for larger developments is a positive thing. Yet the campuses or former infrastructure zones that have been promoted to the development pool happen to be the very few places in Brussels with an ‘excess’ of public and green space. If we are to avoid squandering these areas, it is essential that the regional and municipal authorities provide greater guidance on a third type of densification project: the incremental compaction of not only the contiguously built-up historic and nineteenth-century tissue, but also of the twentieth century built environment.
Twentieth-century belt: opportunities for collectivism
Although a great deal of capacity for densification still exists in the twentieth-century belt, there is still a paucity of vision and methods when it comes to achieving sustainable projects. Indeed, the location for the development of specific projects not only depends on the guiding hand of the authorities, but also on the underlying business models and forms of commissioning or ownership. Moreover, the existing urban fabric, road network and plot size also determine which densification typologies are possible. In a number of garden quarters, projects experiment with densification and a different scale through the introduction of collective residential buildings, such as in the design by Low architects for the social housing quarter Mariëndaal. On privately owned sites, these kinds of projects are less easy to find, and it is also harder to persuade individual owners to commit to building new typologies. In other cities, however, investigations are under way as to how to arrive at a better balance in the distribution of the advantages and disadvantages of densification by also tapping into the potential of the twentieth-century belt.
From compact to polycentric
The ongoing development of Brussels into a compact city is no easy task, and the debate about densification and urban renewal is fuelled by a large number of considerations that can be used to either justify or reject the selection of sites and urban forms. Quarters must be accessible, but mobility should not be the only guiding mechanism. The physical underlayer itself also plays an important role: the soil and the water system, and the open space in and around the city. New challenges thrown up by climate change must also be taken into account, such as heat stress, drought and flooding, as well as those around bringing the city closer towards food production. The city’s economic and industrial backbone determines the possibilities for densification; but the capacity of the urban fabric, street network and the public space also plays a vital role. To ensure that the city continues to be liveable, green and porous, a polycentric model of urban development is more desirable than a concentrically expanding metropolis with a one-sided orientation towards the Pentagon, the city-centre of Brussels. In a polycentric city, densification is concentrated in multiple cores which are connected to one another via a network of public transport and cycling infrastructures, and the twentieth-century belt therefore also needs to be incorporated. This is all the more important because of the space that still exists here for a target group that all too often flees the city: families with children in search of more innovative forms of stacked homes, which are more spacious than those being offered by private developers in the city, and more affordable than classic family homes. Moreover, the twentieth-century belt also offers the potential for a new kind of open space, as the buildings border on large ‘residual spaces’ which can blossom into full-blown metropolitan landscapes. These are green spaces that are easy to open up, which stretch into Flanders, and offer genuine breathing space; and to which compact city dwellers have just as much right as the occupants of the villas on the city’s outskirts.