Terraces and roof top spaces - micro spaces worthy of further consideration

Roof top space as left over space

Whilst the roof-top has been a space that, on the rare occasion, has been celebrated; it has largely been forgotten or ignored within the built environment. At its most architectural, it serves to crown the top of a building. At its most functional, it serves to protect us from the elements. Their visual removal from the social activity of the street or the piano nobile does little to support its cause. It is probably little surprise that roof top accommodation has tended to be the least desirable. In the case of the Georgian terrace, it was where household staff was relegated. Being seated up in the God’s (i.e up in the roof spaces of the auditoria) was the least socially and visually desirable place to be in the theatre. It has become the place where the mechanical plant can be housed. In Hong Kong, they were the reserve of complete shanty communities, forgotten by society and planning processes. Such exploitation of roof rights allows for a greater democratisation of space that capitalises on the inner city economy. It is this latter, more sustainable issue of creating micro communities in the air that we will consider later.

The democratisation of view (Betsky A, 2005 Rooftop architecture, NAI publishers) and the increasing usage of roof-top space for social appropriation, has lifted the loftier realm to becoming a more desirable space. The art deco penthouses of 1930’s Manhattan typified this, celebrating the skyscraper as a visually legible icon within the city and further reiterating the power and identity of both penthouse and occupier. The roof-top penthouse (figure 1) and boardroom (figure 2) are two examples of the status, prestige and arrival engendered in the typologies, and a reflection of an individuals’ lifestyle and / or corporations’ status.

But with half the world’s population now living in inner city centres, and the continued trend towards inner city migration, should we not be challenging the exclusivity and the space intensive penthouse and boardroom or, at the very least, consider complimentary sustainable building programmes or additions that can co-exist? In short, should we not argue for the sustainable democratisation of roof top social space as opposed to just the democratisation of view, or at worst, the acceptance of the roof as the reserve of the privileged?

Living on the roof

The consensus amongst demographers is that the World’s population will increase to at least 9.2 billion people by the year 2050. By 2007, for the first time in human history, more than half the people in the world will be living in cities (UNFPA, 2005). With such a population increase in inner city locations, we are on the cusp of seeing a significant increase in high density, urban development.

The use of roof-tops as a means of expansive adaptation to cater for inner migration had already taken place in Hong Kong, albeit illegally (figure 3). Such contests over space between British and Chinese gave rise to an ambiguity of governance that allowed an almost anarchic appropriation of the city. Whilst sustaining a community that totalled 35,000 people by the 1980’s, the Walled city flew in the face of sanitation and building regulations; becoming a memorable den of inequity that was eventually torn down in 1993.

Little has been done, however, to consider the roof-top potential of topping up existing developments, and should therefore be considered more carefully. Topping up is an old term for building on a roof, often adding the same social, functional and even architectural programme on an existing building in the interests of increasing volume and density. In the 2002 Symposium The Hague in search of an extra 2 million square metres of land and housing, 4 speakers were challenged to each find a quarter of the number of square metres required. Vreedenburgh demonstrated that, by factoring the total number of homes in The Hague (215,000) and their average surface area (79sqm), a total housing surface area of 16,985,000sqm would yield 6329 new homes within the 500,000sqm allocation (figure 4). Factoring in the building land area assigned for housing in the Hague (3,056ha), the buildings age and suitability for roof top construction (40% of 85% worthy properties that could sustain top up architecture, given their flat roofs), the 500,000sqm of rooftop housing would require only 334,000sqm of rooftop surface area(!)(Melet E, Vreedenburgh E, 2005 Rooftop architecture, NAI publishers).

Working on the roof

Madanipour has argued that the European industrial city of the past is becoming de-industrialised and transformed into the service economy city of the present (Madanipour, A, 1999, Why are the design and development of public spaces significant for cities? Environment and Planning B: Planning and design). The cramped environs of the inner city factories of the past, that once housed physically challenging machinery operated by the working classes, have given way to loft style apartments owned by the comfortable middle classes as live / work environments of the present. The Information revolution has seen the factory worker become replaced by the office worker within the service city. Information Technology has also freed the office worker from the shackles of the rank and file of office cubicles, as propagated in the 19^th century by office pioneer, Taylor (Duffy, F, 1997 The new office, Conran Octopus). The office worker can now work where they want, when they want - driven largely by the increasingly complex lifestyles of the individual, the globalisation of working practice and the need to communicate faster across groups, departments, offices, cities, states, countries and time-zones.

Broadway Malyans’ Vertices, a 40-storey bioclimatic office tower in Kuala Lumpur (figure 5), has a series of sky terraces that extend past the floor plate on the east elevation every 5 floors. Intermediate sky gardens then culminate in a roof top garden and restaurant. The spatial intervention of these outdoors spaces provides an opportunity for office workers to work wireless, hold meetings or socially interact. The terraces are partially enclosed by brise soleil that are also vertically planted, providing a protective barrier to the low angle sun and a cool, natural micro environment that acts as a flexible outdoor extension of the office activities.

Playing on the roof

Increasing inner city migration and the new living and working environments will undoubtedly put pressure on the existing socio, economic and recreational infrastructure that sustains the city. The urban vocabulary of street, square, sky way and concourse, and the plethora of recreational and retail activities that have become so intrinsically incorporated into such spaces will need to be expanded upon to cater for physical and social growth. Sky gardens and sky courts could be a worthy addition to the urban vocabulary, as they are recreational social spaces (albeit in the sky) that can also act as a circulatory interchange in roof top structures / tall buildings. With the continued democratisation of space, and the increasing governmental legislation that is supporting the incorporation of more socially sustainable programmes into existing structures, sky gardens and courts could create a new lease of life to roof-tops.

Sky courts and terraces at the pinnacle of tall buildings can provide the opportunity to observe memorable skylines and panoramic views and potentially be a source of income for the developer, as demonstrated most notably in the form of the Empire State building. The building famously weathered the storm of financial crisis in the 30’s great depression through its 86^th floor observation deck that drew visitor receipts of 2 million dollars in the first year of opening – as much money as was taken in rent that year (Tauranac, 1997, Empire State: The making of a landmark, St Martins Griffin, New York).

In terms of recreation amenity, roof top pools, bars and restaurants have become quite conventional in chic inner city hotels; but Toyo Itos’ Vivocity, Singapore (figure 6), has a complete recreational terrace located on the roof of the shopping mall that provides a space for performances, children’s play areas, and hard and soft landscaped features that create a conducive environment that not only improves circulation to and from the various food and beverage outlets and beyond, but also an opportunity for socially interaction.

Growing on the roof

Population increase has similarly meant that we have become even more agriculturally reliant in providing food for the masses. This has historically necessitated the compartmentalisation of 38% of the Earth’s land surface for agricultural land into semi-functional units dedicated to soil based agriculture – much to the detriment of our natural ecosystems. But the increase in world population to 9.2 billion people by 2050 will necessitate an additional area roughly the size of Brazil to create reliable food supplies. The quantum of arable land will not be enough to sustain the global society, potentially creating social dysfunction and chaos on a global scale.

To counteract this, Despommier has considered vertical farming (figure 7). These would allow for year-round food production without loss of yields due to climate change or weather-related events - supplying enough food to comfortably feed society for the foreseeable future whilst allowing large tracts of land to revert to the natural landscape and thus restore ecosystems. It would safely and efficiently use the organic portion of human and agricultural waste to produce energy through methane generation, and at the same time significantly reduces the population of vermin. From a built environment perspective, it could take advantage of abandoned and unused urban spaces and create an environment that encourages sustainable urban life, promoting a state of good health for all those who choose to live in cities (Despommier D, 2005,The Vertical Farm: Reducing the impact of agriculture on eco-system functions and services).

In addition to agricultural production, roof-top gardens help regulate the ecosystem – acting as a respiratory system and a filter of noxious pollutants. It can also counteract urban heat island effect by shading heat absorbent surfaces through evapotranspiration cooling and ultimately help reduce heat gain by between 25-80%. Trees can further assist in cooling the immediate micro-climate, given its retention of larger volumes of air by up to 5 degrees centigrade (Yeang, 2002, Reinventing the skyscraper, Wiley academy). Chicago is a prime example and is one of the greenest cities in the United States, with over 200 LEED certified buildings. Seven years ago it installed its first roof top garden on top of City Hall (figure 8). Today, it has more than 250 gardens and green roofs covering 2.5 million square feet of the built environment (Johnson, S, 2008 Tall and Green, the 8^th world congress on tall buildings, Dubai).

Conclusion

The Vertical terrace and roof top space need not be a forgotten realm, but should be re-celebrated as a space that can support the densification of our cities by providing greater surface area for living, working, playing and growing. They should be able to provide a new lease of life in the sky as vibrant or eye catching as that found on the ground. Subject to ownership and the demarcation of boundaries, they can be a worthy addition to the existing urban space vocabulary of the square, street, arcade, concourse and skyway, the democratization of which allowing for more heterogeneous, mixed use environments that can enrich our daily lives and potentially create more colourful 24 hour environments.

As a living space, they would help solve the increasing inner city migration issues by providing new homes without compromising land area or the existing urban grain. As a working space, they have the ability of enhancing our lives by providing a greater freedom of working in congenial outdoor settings. As a playing space, they allow us to enjoy pleasant skyline views or partake in recreational activities that can support health and well-being. As a growing space, they can even provide food in order to sustain communities. As a bio-climatic space, it can mitigate the impact of building development through the balancing of carbon emissions.

Picture credits

(Figure 1,2,4,7,8 )Melet E, Vreedenburgh E, 2005 Rooftop architecture, NAI publishers

(Figure 3, 6) Author’s own

(Figure 5) Broadway Malyan

(Figure 7) Dickson Despommier

Hong Kong Central-Mid-Levels Walkway

01. Soho, in Hong Kong, is characterised by a high density built environment planned along steep streets that would appear to be difficult to circulate. Nevertheless, it has survived as an area rich in eateries and street front activity at the cross streets (which are level), meaning that the primary circulatory means have proven to be more challenging given their gradient. The net effect of this is that the cross streets appear to be more densely populated, and the primary streets rather sparse in activity.

02. The incorporation of travellators have improved circulation, demonstrated by the numbers of people who use it to traverse up and through to the cross streets of Soho. It is a physical imposition into the urban environment that seems to be unaffected by the buildings around it – rather, it is an insertion that physically replicates what is the open space beneath, yet provides an ease of motion for the pedestrian.

03. As one can appreciate in the humid climate of Hong Kong, physical assertion by climbing steps is mitigated by the travellator, with the easier option of downward circulation being catered for by steps.

04. Despite its extensive usage, there are limitations. Whilst a public space, it has particularly explicit rules of use, manifest in its operating hours and restrictions of appropriation, which has more to do with movement (do not walk against the flow of traffic, do not obstruct, do not play, do not lean out).

05. The travellator, as a skyway structure creates a shaded opportunity that is reasonably taken care of as a social space, with limited planting and steps to take up the level differences. These steps are used as seats for migrant workers to relax and socially interact at the weekend.

06. This group of Filipino maids congregate under the skyway travellator every weekend, along with many hundereds more, as it is one of the few open spaces that allow for such communal activity under shade other than the air conditioned environs of the retail mall and arcade. In conversation with the maids, I asked why they didn’t congregate within the mall environments. Their response was that they did ‘not feel comfortable’; were ‘not able to bring food inside [the retail environments]’ or lepak kaki (sit around in an idol fashion). In and above the explicit rules that govern the usage of semi-public domains of the retail environments, there also appears to be implicit social exclusions that negates the opportunity of the migrant workers to use the internal spaces; pushing them to the perimeters whereby the public arena allows them to congregate, set up camp and interact within the social clusters.

07. The travellator has become such an intrinsic part of the pedestrian movement across multiple levels that new developments have attached themselves to it – presumably in order to capture the passing footfall for trade and provide an ease of movement.

08. Moving up through this zone, I was amazed to find another gatherings of migrant workers, though this time setting camp within the transitional space that forms an overhead link to a busy highway. One side is lined with retail units, many of which were closed at the time. The central space between the shop façades and the columns was free for the regular passage of pedestrians. The columns to the external wall that forms the enclosure demarcated a space that has been appropriated by the migrant workers as a resting / social area at the weekends. There appropriation does not disrupt the flow of pedestrians traversing through the central space. The space within this zone is then further physically demarcated by the individual or social groupings. In the case of the former, setting clothing on the ground demarcate their zone. In the latter, cardboard mats demarcate a territory, from which the social grouping will sit. Further protective temporary boundaries are erected in the form of umbrellas that presumably provide an element of privacy, a screen to dust and a territorial boundary from which the individual groups feel sheltered from either other groupings or passers-by.

09. Following through this transitional thoroughfare, I came across a further space that was again filled with migrant workers. The space was narrower, and this time open air, all bar a roof covering and a glazed handrail. This appeared to be less populated than the previous.

10. Moving further in again, I came across a space that wasn’t inhabited at all, but still appeared to retain the same quantum of footfall. The assumption may be drawn that the external environment may have been harsher. There was a higher audible level of noise from the streets that could make casual conversation difficult. There was also a greater amount of exposure in terms of daylight penetration due to the narrower width of concourse. The narrower width would also presumably reduce the space that could be taken for relaxation by the migrant workers given the need to keep a free passage for passing footfall. Should the migrant workers have occupied the space as they felt accustomed to in the vicinity, they may have compromised the ease of passage for others, creating possible tensions and the perception that they would have been territorially taking ownership of the space. On the other hand, their respectful retention of the free passageway may have restricted their own appropriation of the space, forcing them to adopt different social techniques to engage with each other in public. When compared with the previous concourse and its column position, the patterns would suggest that the physical structure that is highly legible demarcates an acceptable space to one side of it that can be used by the migrant workers. The absence of the structure in the other concourse goes unchallenged and so remains simply as a concourse for pedestrians.