Cost Model Tall Buildings For Building Magazine March 2020 Cost Model Tall Buildings | For Building Magazine Cost Model Tall Buildings London was slow to adopt tower building but the City’s distinctive skyline shows how much attitudes have changed. Steve Watts of alinea looks at what needs to be considered when constructing a skyscraper in the UK, while the architect behind 22 Bishopsgate talks though its design process 01 / INTRODUCTION The UK has had a relatively short and considering there are about 1,600 buildings of While not all these projects will come to fruition, somewhat tempestuous relationship with such height in the world. there will be others not currently in the public tall buildings. New construction projects But it seems tall buildings are here to stay. realm to add to the total. Whatever the number, draw controversy about appropriateness of The Tall Buildings Study 2019 by New London’s skyline will be changed irrevocably, scale, location and their role in helping (or London Architecture suggested the capital’s centred around a growing cluster of high- exacerbating) the housing crisis. To date, tall buildings pipeline (towers of at least quality commercial towers. The city will have to only five buildings of 200m or higher have 20 storeys) totalled 541, of which 291 had reconcile its unease around high towers. been completed, all in London, and most are permissions and 121 were under construction. commercial office buildings – a small number 02 / HEIGHT IN THE UK A slow start east of the City not only became sustainably in highly-accessible number of residents in its London’s first wave of skyscrapers a successful, high-rise business locations.” history. Like other cities that arrived late in global terms, with district in its own right, but From no to yes: Ken Livingstone deindustrialised after the Second the “mini boom” of the 1960s. provided the pre-catalyst for The biggest boost to building World War, London’s population The height of St Paul’s Cathedral the City’s acceptance of the tall upwards came with the election initially peaked in 1939, at 8.6 (finished 1675) was not surpassed building typology, as the City of Ken Livingstone as mayor of million, before consistently until Millbank Tower was completed Corporation sensed a threat on its London in 2000. As the first mayor falling, until in 1981 it had only in 1963. The two decades that own doorstep as well from other elected under the Greater London 6.6 million residents. Since then, followed were quiet in terms financial centres such as Frankfurt. Authority Act, he was given more the population has rebounded. of tower construction, with a The City’s response was watched say over the city’s real estate In 2015, the number of people few notable examples including over by Peter Wynne Rees, who development. finally surpassed its earlier peak, Tower 42 (then NatWest Tower), and London is still growing began nearly 30 years as chief His strategy received strong push- completed in 1980 after an (notwithstanding what impact planning officer in 1985. He back from a coalition of opponents, incredibly long gestation. Some Brexit might have) – a trend summed up the advantages of most notably conservation groups wondered if towers could ever sit repeated elsewhere in global tall densification as: “Towers can such as English Heritage and comfortably in London’s historic, metropolises, as economic growth increase the economic strength SAVE Britain’s Heritage. He was low-rise environment. becomes even more focused and vitality of a successful central able to overcome the naysayers, around huge cities. Canary Wharf business district by clustering in part because the towers were The 39ha of docklands to the specialised business activity touted as high-quality landmark Between 2005 and 2018, London’s structures designed by world- total employment grew by nearly renowned architects. Today, a crop 30%, more than that of the country of landmark towers in and around as a whole – today, it employs 17% the city are internationally admired of the UK workforce. for their architectural designs and Another encouragement is the engineering feats. international desire to enjoy London’s culture and amenities. Why the change? Rising global incomes have While London’s embracing of increasingly made London a skyscrapers was promoted by draw for tourism and foreign Livingstone, their construction investment. Between 2002 and reflects a greater need. The city has 2018, international tourist visits benefited from several economic to London increased by 64%. and demographic forces that put London’s high-rise structures are in pressure on its land values and some respects both a response to increased the interest in valuable and cause of this, as tourists are as central locations. In other words, likely to be interested in enjoying one can say Livingstone’s campaign the delights of the Sky Garden at was about opening a “safety 20 Fenchurch Street as they are valve” that freed the real estate in the heritage of the Tower of community to satisfy the growing London they see through its glass. demand for tall buildings. The first factor was population International capital flows London is home to a plethora of skyscrapers after a growth. At around 8.9 million Recent times have witnessed boost during Ken Livingstone’s time as mayor people, London has the highest a level of interconnectedness 2 Cost Model Tall Buildings | For Building Magazine Cost Model Tall Buildings between global cities never seen towers are owned by international three-and-a-half years. by a consortium of funders. Its before. International money funds, and many future ones will 22 Bishopsgate, the tallest building architect, Karen Cook of PLP, has flowed across the world in be backed by foreign money, in the City of London, which is explains below how the building search of a diversified investment as London retains its long-term heading for imminent completion, came about and what underpins portfolio, and long-term returns inherent advantages, despite the is a prominent example of a its design. from tall, trophy assets. Many political uncertainties of the last game-changing tower backed 03 / 22 BISHOPSGATE - THE MAKING OF A NEXT-GENERATION TALL BUILDING Stuart Lipton and Peter Rogers approached me in 2012 to embark on a journey to explore the stalled Pinnacle site in the heart of the City of London, writes Karen Cook. The Pinnacle, the design of which I led while at my former practice, began in 2003. Its form tapered to small floorplates at the top, defined by inclined planes and cones, resulting in numerous steel frame connection details. The steel frame core meant the perimeter steel frame had to work hard, correlating into heavy steel members. A decade later, key design factors had changed. Stricter energy regulations and substantially higher occupation density, which increased from one person per 12m2 to one person per 8m2, required more and faster lifts, wider staircases, more fresh air – greater infrastructure that did not fit into the Pinnacle core footprint. How could we approach a new design for a familiar site? Post-global financial crisis, the City planners preferred a simple yet powerful glass tower to tie together the emerging skyline, with increased focus on public realm experience. Lipton Rogers Developments’ brief required a new design of enduring architectural qualities to the latest specification that was affordable to build with large floorplates all the way up, alongside public realm contributions. Stuart introduced a “vertical village” of amenities to give individuals choice and convenience, from cycle parking to an 22 Bishopsgate has repetitive steel frame components, a single facade cladding urban market, project co-working space, a type, and reuses the Pinnacle foundations gym, a spa and a club. The critical mass of a large tower means small tenants can compete against big companies to attract talent with 22 Bishopsgate’s curated amenities, where people fold, giving alternating readings of London’s to Europe’s fastest double-deck lifts and the can meet outside the office, exchange and test ever-changing skies. Low-iron glass with Market food court. Curated changing artwork ideas, be stimulated or relax. a light, silvery coating appears alternately animates the space and the street. Bespoke transparent, reflective or milky white. A closed sculptural furniture by Pierre Renart with Redistributing the construction budget to cavity facade with internal, operable, movable handcrafted leather by Bill Amberg create a pay for a variety of spaces to host the vertical blinds transmits some 60% more daylight calm cocoon in the reception, and paintings village and fundamental environmental than comparably performing double glazing. by Bruce McLean add to the body of art, qualities such as better daylight, better fresh The top steps to lead the eye skyward, with contributing to the singular identity of 22 air, higher ceilings and a free-to-public-access six levels of space outside the office including Bishopsgate. viewing gallery required a pragmatic approach restaurants, an external terrace and London’s to construction. Stuart and Peter stipulated highest free-to-access public viewing gallery. Karen Cook is a partner at PLP Architecture the use of repetitive steel frame components, a single facade cladding type, and the re-use of Cyclists’ and pedestrians’ commutes are the 65m-deep Pinnacle foundations, which pre- improved by consolidated delivery, forecast determined column locations. WSP proposed to reduce vehicle trips by as much as 70%, a concrete core to activate the raft, with which 22 Bishopsgate introduced to the City. outriggers to increase stiffness, resulting in a Alexander Beleschenko’s artwork incorporates lighter perimeter steel frame. 22 Bishopsgate colourful glass panels into wind mitigation has 40% more area, while its steel frame weighs canopies and along the new pedestrian route 15% less than the Pinnacle.