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

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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 foorplates at the top, defned 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 ft into the Pinnacle core footprint.

How could we approach a new design for a familiar site? Post-global fnancial 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 specifcation that was affordable to build with large foorplates 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, refective 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. across the site connecting Bishopsgate to Crosby Square, enriching the pedestrian The building is an abstract approach to experience. In the main foyer, a four-storey form, responding to light – 23 vertical facets series of spaces with multiple entrances leads

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Cost Model Tall Buildings

04 / DESIGN TRENDS

In global terms, London’s current wave of provision for socialising activities such as commercial tall buildings has delivered an array yoga and fitness, with a design that supports of forms with an investment in high-quality healthiness through encouraging stair use specifications underpinning imaginative design and other activity. responses to the constraints of planning and • Contemporary feel – design is evolving fast; historic, irregular sites. exposing structure and services components Designs continue to develop in response is becoming the norm. to emerging trends in technology, the • Cycles and showers – given the size of a requirements of modern occupiers, new tall building in floor area terms, the scale of regulations and ideas from around the world. town planning-driven facilities for cyclists is No longer are City of London offices and considerable. tall buildings the domain of major corporate • Environment – regulatory changes pushed by occupiers focused around the banking, finance the London Plan, the greening agenda in the and legal sectors – occupier profile is changing City of London and the desire of occupiers as technology and non-financial businesses for their property to be carbon-friendly. move into the Square Mile. Additionally, evolving • Wind – the impact upon the street plane is market trends and regulatory changes are being better defined and understood by town having a significant impact on the briefing of planners; more stringent conditions are being design teams and the future of office design, put upon designers to model and test this to the implications of which can be amplified in mitigate impacts to pedestrians. tall buildings and have a bearing on cost. These • Public access – the ability of the public to include: access views from tall buildings is often conditioned through planning, so the impact • Flexibility – tenants are seeking increasingly upon access, lifting and security needs careful flexible leasing terms, requiring designs to consideration. incorporate flexibility and sub-divisibility in • Entrance experience – the way towers greet floorplates. the public is being given greater thought, • Interactions – tenants want their people to with a more seamless and welcoming journey enjoy areas where they can gather and draw from outside to inside, an imaginative mix of benefit from specialist facilities to support retail and other functions in more generous their business interactions, encouraged by volumes at lower levels, and a contribution floorplate connectivity and flexibility within to the horizontal connections across the City spaces. ground plane. • Being smart – technology, connectivity The ‘climbing window’ at 22 Bishopsgate is and resilience drive occupier business following the trend for wellness requirements. • Wellness – welcoming common spaces and 05 / KEY COST DRIVERS

Tall buildings live on the edge Efficiency of form between basement construction will occur if the structure is financially, relying on the design Shape is the most important of and the commencement of the integrated into the external zone, team to work together to address the key cost drivers, because core/vertical structure is a key which is why the cost consultant the inherent challenges of time, it directly impacts the scale, area of focus for programme and will advocate avoiding this unless cost and floor area inefficiencies. configuration and regularity cost. The earlier the superstructure there is a good reason otherwise. There is an intense and sometimes of floors. Cost, floor area and construction can commence the complex relationship between the construction efficiencies are all better, meaning that investment Fire strategy three points of this commercial unquestionably impacted by the in partial or full top-down The early engagement of an “golden triangle” but achieving shape of a tower – not least the construction is appropriate to experienced fire consultant is a a balance of these across the size of the floorplates, as core and mitigate time and programme risk. critical part of testing conceptual design’s principal elements is structural zones expand relative The majority of office high-rises design options and ensuring a safe critical for success. to the overall floorplate to satisfy are steel framed with composite and robust strategy is developed In the early stages of a tall the requirements of vertical floor slabs, whereas residential in the most cost-effective way, building design, it is therefore circulation, servicing and wind have concrete structure and floors. through fire-engineering of important that key design loadings. The wall:floor ratio, (the Stability cores are often concrete, appropriate members aligned criteria, and how these drive area of facade required to clad with construction advancing with the design implications of costs, are understood and used floors), a key indicator of cost ahead of structural floors. Steel evacuation strategies. This has to help design strategy, define efficiency, is directly impacted by design efficiency can vary by as become even more important construction costs, improve floor the size and shape of floors. much as 100%, depending on the in the post-Grenfell world of area efficiencies and prompt location of the core, the height increased regulatory scrutiny. considerations of construction Structure and shape of the building, beam As tall buildings are pushed to techniques. Fundamentally at The scale and mass of the spans and other factors. the limits of site ownership to concept stage, the following building has a direct impact on maximise lettable areas, it is more foundations, with a tipping point The current trend for exposing will drive costs and commercial and expressing structural elements common to consider drenching performance more than anything for larger bentonite piles being façades to overcome fire-spread around 30 floors. for architectural interest adds to else: cost but like everything else needs to adjacent properties, which can Understanding the construction to be balanced against the value be complicated by the preferred and programme relationship created. Particular complexities façades solution.

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Cost Model Tall Buildings

Facades sophisticated blind controls, carefully when reviewing capital on core design, with cost, Shape and form aside, a key should be a reference point – construction cost against space- space-take and operational user- priority for facade design is the 22 Bishopsgate is an example take. A key cost decision for friendliness all important factors maximisation of daylight alongside of successful procurement electrical installations is high on the decision. Double-deck lifts efficient thermal performance and installation of more than versus low voltage distribution. are common, which brings about and control of solar gain. Given 50,000m2 of closed-cavity facade An effective strategy is to locate design considerations, such as a the prominence of a tall building, walls. high voltage transformers close to multi-storey reception lobby and the architectural response to large electrical load centres, with associated escalators, to allow townscape needs careful thought, Mechanical, electrical, public other plant at the bottom and top access to both the upper and but in any event, maximising health of the building. Lifting generators lower cars, balanced by a strategy repetition through restricting An early major decision for onto the roof of a finished for the entire tower that is often system types, minimising depth mechanical systems is plant tower is problematic, so unless cost-effective and area-efficient. of facade zones and ensuring location: central, interstitial or space can be found lower in the efficiency of construction through floor-by-floor. Buildings of more building then full building back-up Procurement and programme pre-assembly is key. The advance than 20 storeys require multiple resilience is generally a base build The scale and complexity of tall in technology of pre-assembled distribution risers and hydraulic provision. buildings means the gestation and tested closed-cavity facade separation to reduce the pressure period is considerable: projects systems, with the ability to control rating on the pipework, valves Vertical transportation take longer to get to site and heat gain through a ventilated and plant. Therefore, plant and The vertical transportation more time to build, so there is facade and glare through riser space need to be considered strategy has a significant impact an absolute need to be focused on programme efficiency and productivity. There is greater risk during construction due to logistics and movement of labour and materials at height and wind restrictions around tower cranes. Focusing on prefabrication of façades and modularisation of elements such as risers and plant rooms eases the pressure on hook time and site labour. Making the labour force as productive as possible is not to be undervalued. Offsite consolidation and a sophisticated logistics strategy should be considered. The supply chain is a more constrained pool for these projects, so early engagement of specialists is recommended to secure resources and benefit from their knowledge.

A new pedestrian route across the 22 Bishopsgate site connects Bishopsgate to Crosby Square

06 / ABOUT THE COST MODEL

The challenges of the “golden The shell and core construction Our cost model summarises the two-stage process, converted to triangle” for tall buildings – costs for central London office shell core elemental costs of a a lump sum. It includes all main especially acute when shape towers can be grouped as follows, notional 45-storey office tower contractor preliminaries, fees and form are working against primarily influenced by the in central London, with a gross and risk allowance to complete them – necessitate a focus on the architectural response to a site internal floor area of 82,700m2 the building to a shell and core micro as well as the macro. Teams and its interface with the required including three basements. It status. Demolition, enabling need to constantly challenge structural solution, followed by achieves an overall net-to-gross works, external works, external the developing design and look overall specification levels and ratio of 64%, a wall-to-floor ratio services, category A fit-out, for marginal gains across the then height: of 0.45 and its steel frame weighs tenant enhancements /fitting- building’s elements to maximise an average 110kg/m2 above ground out, professional fees VAT and all economies of scale and avoid • Larger sites, regular and larger gross internal floor area. developer’s costs are excluded. diseconomies. The premium for footprint schemes – £3,300/m2- building tall can be considerable, £3,500/m2 (gross internal area) It achieves BREEAM Excellent, but equally it can be managed to Q More constrained sites with WiredScore Platinum and its base a much smaller “tall surcharge” if townscape challenges – £3,500/ build is WELL Building Standard- the team works together from the m2-£4,000/m2 (gross internal enabled. beginning to optimise the form area) and the design strategies that Costs are base dated at underpin it, then do likewise to • Constrained sites, taller and January 2020 and the model hone the details. more complex geometry – reflects prices obtained from a £4,000/m2-4,500/m2 (gross competitive tender through a internal area).

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Cost Model Tall Buildings

07 / COST MODEL FOR A 45-STOREY OFFICE TOWER IN CENTRAL LONDON

Element cost Cost/m2 GIFA % total cost (£) (£) Substructure 24,381,000 294.81 7.6 Frame 48,213,500 582.99 15 Upper foors 11,604,000 140.31 3.6 Roof 3,075,000 37.18 1.0 Stairs 4,225,500 51.09 1.3 External walls 40,869,000 494.18 12.8 Windows and external doors 1,210,000 14.63 0.4 Internal walls and partitions 5,526,000 66.82 1.7 Internal doors 4,503,700 54.46 1.4 Wall fnishes 2,070,000 25.03 0.6 Floor fnishes 3,092,000 37.39 1.0 Ceiling fnishes 1,504,000 18.19 0.5 Sanitary appliances and WC fnishes ft-out 15,250,000 184.40 4.8 Fittings, furnishings and equipment 1,800,000 21.77 0.6 Lifts and escalators 16,500,000 199.52 5.1 Disposal installations 1,820,250 22.01 0.6 Water installations 1,955,000 23.64 0.6 Heat source 566,000 6.84 0.2 Space heating and air treatment 20,018,500 242.06 6.2 Ventilation systems 3,680,000 44.50 1.1 Electrical installation 16,364,000 197.87 5.1 Gas installation 206,750 2.50 0.1 Protective installations 2,722,500 32.92 0.8 Communications, security and controls installations 7,288,200 88.13 2.3 Builders’ work and fre stopping etc 2,200,000 26.60 0.7 Preliminaries and contingencies 79,818,000 965.16 24.9 Main contractor preliminaries costs and OH&P approx 22% + risk transfer at 4% and construction contingency at 5% TOTAL SHELL AND CORE 320,462,900 3,875.00 100.0 (excluding demolition, external works, external services, category A fit-out, tenant enhancement, professional fees and VAT)

For the full cost model, showing a full breakdown of all the costs, main contractor preliminaries, fees, and risk allowances, go to www.building.co.uk/tall-buildings

Acknowledgments The authors would like to acknowledge the contribution of Steve Watts, Mark Lacey, and Jay Pearman of Alinea; Jason Barr, Rutgers University; Karen Cook, PLP; and Sir Stuart Lipton of Lipton Rogers

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Cost Model Tall Buildings

Element Cost/m2 % total Element Cost/m2 % total cost GIFA (£) cost cost GIFA (£) cost Fire protection – 90 minutes Substructure 24,381,000 294.81 7.6 5,440,500 intumescent (8,370t @ £650) Breaking out existing slabs, up-fll, piling 1,100,000 matt and guide walls and pile probing Temporary works for tower cranes, 1,700,000 (1 @ £1,100,000) access and edge protection etc (1 @ £1,700,000) Secant pile wall to perimeter, including 3,600,000 removal of arisings and sonic testing Reinforced concrete core walls, including 14,650,000 (200m @ £18,000) cast in connections, RC beams etc. (29,300m2 @ £500) New piled foundations, including 4,400,000 mobilisation, coring, test pile, removal of Upper foors 11,604,000 140.31 3.6 arisings and sonic testing (2,200m2 @ Reinforced concrete slabs including 7,284,000 £2,000) metal profled decking including stubs Excavation to lowered formation levels 2,500,000 etc (60,700m2 @ £120) 25,000m2 @ £100) Reinforced concrete slabs 200thk to 1,140,000 Temporary plunge columns, king 3,213,000 cores (5,700m2 @ £200) posts to perimeter, site cross propping Allowance for enhancing loading 200,000 including connections, adaptions and capacity of slabs to other core areas removal (630t @ £5,100) (1 @ £200,000) Raft Slab 1.5m thk, including pile caps, 3,410,000 Perimeter detail, down stand beams, soft 1,000,000 blinding beds, construction joints, spots, plinths, etc (1 @ £1,000,000) worked fnish, cast in base plates, waterproofng (2,200m2 @ £1,550) Allowance for metal platforms to risers 1,780,000 for temporary protection and permanent Reinforced concrete capping beam, 800,000 condition (1,780m2 @ £1,000) including couplers for slabs, removal of guide walls, waterproofng and Allowance for lift and escalator pits etc 200,000 temporary work nibs and making good (1 @ £200,000) (200m @ £4,000) Roof 3,075,000 37.18 1.0 Reinforced concrete liner walls to 1,400,000 perimeter, 300thk including flling works, Allowance for cladding lift core overruns, 200,000 waterproofng and works to existing cappings and the like (1 @ £200,000) walls (2,800m2 @ £500) Allowance for insulation and 217,000 waterproofng ground roof slab areas Reinforced concrete ground foor slab 368,000 2 350thk (1,600m2 @ £230) (620m @ £350) Extra over allowance for foor logistics 300,000 Inverted roof, including waterproofng, 1,638,000 slab 500thk, including temporary insulation, ballast, blueroof, natural protection (500m2 @ £600) stone, paving, pitch pockets, drainage channels and sundries (2,600m2 @ Reinforced concrete structures to 1,800,000 £630) basement levels 1, 2 and 3 (4,500m2 @ £400) Allowance for landscape to viewing 800,000 terrace, including planting, irrigation Allowance for lift/escalator pits 150,000 system, integrated seating, lighting and (1 @ £150,000) sundries (1 @ £800,000) Allowance for tower crane base to 90,000 Allowance for waterproofng and 120,000 basement slab (1 @ £90k) insulation to internal plant areas Allowance for dewatering site 200,000 including pavers (400m2 @ £300) (1 @ £200,000) Allowance for roof service enclosures, 100,000 Allowance for movement monitoring 250,000 roof hatch and sundries (1 @ £250,000) (1 @ £100,000)

Allowance for below slab drainage 300,000 Stairs 4,225,500 51.09 1.3 (1 @ £300,000) Painted mild steel escape stairs, 3,546,000 Allowance for all other items and 500,000 including treads, perimeter handrail and sundries (1 @ £500,000) central balustrade (197nr @ £18,000) Ditto, allowance for basement stairs 379,500 SUPERSTRUCTURE (23nr @ £16,500) Allowance for ladders, steps and 200,000 Frame 48,213,500 582.99 15 catwalks to plant rooms (1 @ £200,000) Steel frame, beams columns and 24,273,000 bracings (8,370t @ £2,900) Allowance for stopovers, ladders and 100,000 access platforms to external areas Allowance for frame complexity in steel 400,000 (1 @ £100,000) connections and sundries (1 @ £400,000) External walls 40,869,000 494.18 12.8 Secondary steelwork for cladding, 1,750,000 Allowance for facade PCSA, visual 1,000,000 embedment plates, temporary stability mock-ups (VMUs), prototype mock-ups for hoists and cranes etc (PMU’s) and all other facade related (1 @ £1,750,000) testing (1 @ £1,000,000)

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Cost Model Tall Buildings

Element Cost/m2 % total Element Cost/m2 % total cost GIFA (£) cost cost GIFA (£) cost Main façades, assume double skin Leaf and a half door generally (218nr @ 763,000 unitised curtain wall with integrated 23,456,500 £3,500) 2 solar control blinds (21,820m @ £1,075) Double doors generally (20nr @ £4,000) 80,000 Plant area façades, unitised curtain wall 1,870,000 Glazed doors to lift lobbies with side 675,000 2 including louvres (1,700m @ £1,100) screens (45nr @ £15,000) Allowance for aluminium plant room 400,000 Riser doors, ranges from 30mins to 975,700 screens/enclosures (1 @ £400,000) 60mins FR (887nr @ £1,100) Reception façades, steel stick system, 1,250,000 Plant double doors, ranges from 60mins 380,000 double glazed low iron glass to 120mins FR (95nr @ £4,000) (1,000m2 @ £1,250) Allowance for access panels to walls 100,000 Core façades, unitised curtain wall, solid 7,517,500 generally (1 @ £100,000) aluminium panels, glazed where required (9,700m2 @ £775m2) Allowance for smoke and fre curtains 120,000 throughout (1 @ £120,000) Allowance for soffits (700m2 @ £1,100) 770,000 Allowance for doors to basement plant 550,000 Balustrades, copings and parapet 455,000 and circulation areas generally fashings (350m @ £1,300) (1 @ £550,000) Allowance for façade penetrations, 100,000 Doors to goods lifts (65nr @ £4,000) 260,000 including aircraft warning lights, street lighting and CCTV (1 @ £100,000) Wall fnishes 2,070,000 25.03 0.6 Allowance for façade cleaning 1,500,000 equipment (1 @ £1,500,000) Feature wall fnish to reception walls and 650,000 detailing to doors (1,000m2 @ £650) Allowance for enclosure to cleaning 500,000 equipment and sundry fall protection Enhanced plasterboard wall to lift 725,000 systems (1 @ 500,000) lobbies + lift architraves (2,900m2 @ £250) Allowance for external column cladding 150,000 generally (1 @ £150,000) Feature wall fnish to public space 225,000 (450m2 @ £500 Allowance for external walls in loading 200,000 bay (1 @ £200,000) Paint to drylining and blockwork above 350,000 ground (1 @ £350,000) Allowance for wind mitigation measures 1,000,000 Paint to blockwork below ground 120,000 (1 @ £1,000,000) (1 @ £120,000) Allowance for façade blind control 700,000 system to double skin façade Floor fnishes 3,092,000 37.39 1.0 (1 @ £700,000) Natural stone to the reception and lift 1,380,000 cars including matwells and perimeter Windows and external doors 1,210,000 14.63 0.4 trench grills etc (2,300m2 @ £600 Main entrance revolving doors 600,000 Natural stone to lift lobbies 580,000 (5nr @ £120,000) (1,450m2 @ £400) Single leaf pass doors generally 50,000 Natural stone to public space 312,000 (5nr @ £10,000) (780m2 @ £400) Sliding doors to roof terraces 160,000 Epoxy fnish to plant areas above ground 273,000 (8nr @ £20,000) incl. access (3,900m2 @ £70) Sundry escape doors, roller shutters, 250,000 Rubber sheet foor to Landlord areas 147,000 external plant access doors and panels above ground (980m2 @ £150) etc (1 @ £250,000) Allowance for plant and circulation area 350,000 Allowance for loading bay entrance 150,000 fnish below ground (1 @ £350,000) gates (1 @ £150,000) Screeds, earthing to EDF and other plant 50,000 areas (1 @ 50,000) Internal walls and partitions 5,526,000 66.82 1.7 Ceiling fnishes Drywall partitions throughout, mix of 1,584,000 1,504,000 18.19 0.5 30mins to 120mins FR walls Feature ceiling to reception 805,000 2 (13,200m2 @ £120) (2,300m @ £350) Feature drylined ceiling to lift lobbies Shaft walls to risers throughout, range of 1,470,000 290,000 60mins to 120mins FR walls (1,450 @ £200) (9,800m2 @ £150) Feature ceiling to public space 234,000 (780m2 @ £300) Plasterboard lining throughout to face of 700,000 cores (14,000m2 @ £50) Allowance for plant and circulation areas 115,000 above ground (1 @ £115,000) Blockwork to plant areas throughout 1,100,000 Allowance for plant and circulation area 2 60,000 (5,500m @ £200) below ground (1 @ £60,000 E/O for colt walls, acoustic 600,000 Sanitary appliances and fnishes ft-out enhancements, interfaces with steelwork 15,250,000 184.40 4.8 (1 @ 600,000) Allowance for WC ft out throughout, 12,950,000 including fnishes, sanitaryware, cubicles, Four hours brick wall to EDF enclosure 72,000 and other areas (150m2 @ £480) fxtures and fttings etc (3,500m2 @ £3,700) Internal doors 4,503,700 54.46 1.4 Allowance for basement cycle shower 1,800,000 Single doors generally (240nr @ £2,500) 600,000 ft out, including fnishes, sanitaryware, cubicles, fxtures and fttings etc (600m2 @ £3,000) 8 Cost Model Tall Buildings | For Building Magazine

Cost Model Tall Buildings

Element Cost/m2 % total Element Cost/m2 % total cost GIFA (£) cost cost GIFA (£) cost Allowance for landlord areas ft-out, Closed circuit cooling towers 1,947,500 showers, changing rooms etc (1 @ 500,000 (9,500kw @ £205/kw) £500,000) Condenser water installation incl water 1,654,000 softening plant (82,700m2 @ £20) Fittings, furnishings and equipment 1,800,000 21.77 0.6 Chilled water including pumps, 3,721,500 Allowance for main entrance reception 250,000 pressurisation units, pipework, risers, 2 desk and security desks (1 @ £250,000) valves and fttings (82,700m @ £45) Allowance for internal signage 300,000 LTHW water including pumps, 3,308,000 throughout (1 @ £300,000) pressurisation units, pipework, risers, valves and fttings (82,700m2 @ £40) Allowance for external building signage 50,000 (1 @ £50,000 On-foor supply and extraction AHUs 4,650,000 (1 @ £4,650,000) Allowance for high quality balustrades, 250,000 security lines and handrails throughout Supply and extract ductwork for AHUs 2,067,500 (1 @ £250,000) to office foors, including dampers (82,700m2 @ £25) Allowance for cycle racks 200,000 (1 @ £200,000) Air-conditioning to entrance area 500,000 (1 @ £500,000) Security turnstiles to reception 500,000 (20nr @ £25,000) Supplementary DX cooling systems 650,000 Security bag scanners - reception and 100,000 (1 @ £650,000) basement (2nr @ £50,000) Ventilation systems 3,680,000 44.50 1.1 Allowance for rubbish compactor 50,000 Onfoor WC supply and extract system 700,000 (1 @ £50,000) (1 @ £700,000) Allowance for other miscellaneous 100,000 Supply and extraction AHU and 350,000 fttings, column guards, bollards to distribution serving basement shower loading bay etc (1 @ £100,000) area (1 @ £350,000) Lifts and escalators 16,500,000 199.52 5.1 Basement ventilation system (1 @ 1,850,000 £1,850,000) Lift installations; double deck to low, 16,500,000 medium and high rise passenger lifts; Fire fghting lobby vent, mechanically 780,000 goods lifts (2nr); fre-fghting lifts; assisted BRE type system escalators to reception; basement access (65 landings @ £12,000) lift (1 @ £16,500,000) Electrical installation 16,364,000 197.87 5.1 Disposal installations 1,820,250 22.01 0.6 HV distribution: 11kV incoming mains; 1,240,500 Rainwater installation including 372,150 distribution through building 2 attenuation tank (82,700m2 @ £4.50) (82,700m @ £15) LV distribution, including switchgear, 4,135,000 Soil waste and vent to sanitary 1,200,000 cables, rising busbars, etc appliances including grey water (82,700m2 @ £50) collection, fnal run-outs in toilet ft-out (1 @ £1,200,000) Full building back-up generation, 4,704,000 including fues and oil storage 2 Condensate drainage (82,700m @ £3) 248,100 (9,600KVA @ £490Kva) Water installations 1,955,000 23.64 0.6 Power management system SCADA 500,000 (1 @ £500,000) Allowance for incoming MCWS, storage 400,000 tank, booster, meter, water conditioner Power to mechanical services 413,500 2 and distribution pipework (82,700m @ £5) (1 @ £400,000) Landlord’s small power installations 413,500 2 Cold water service to sanitary appliances 915,000 (82,700m @ £5) to risers, run-outs in toilet ftout Lighting to landlord areas, circulation, lift 1,500,000 (1 @ £915,000) lobbies, shower areas, lighting control, Central hot water generation and risers 130,000 etc (1 @ £1,500,000) to ft-out area (1 @ £130,000) Lighting Control (82,700m2 @ £6) 496,200 Grey water installation incl all fltration 450,000 and storage to WCs, run-outs in toilet Feature lighting to reception 750,000 ft-out (1 @ £450,000) (1 @ £750,000) Aircraft warning lights (1 @ £40,000) Non-potable water incl Cat 5 60,000 40,000 (1 @ £60,000) Allowance for feature external lighting 500,000 (1 @ £500,000) Heat source 566,000 6.84 0.2 Containment for security/ CCTV/fre 1,157,800 Gas fred condensing boiler incl delivery 350,000 alarms/ communications and plant movement (82,700m2 @ £14) (5,000kw @ £70/kw) Earthing and bonding (82,700m2 @ £5) Heat pump, including delivery and plant 157,500 413,500 movement (450kW @ £350/kW) Allowance for PV installations 100,000 Flues from boilers to atmosphere 58,500 (1 @ £100,000) (90m @£650) Gas installation 206,750 2.50 0.1 Gas installation to boilers Space heating and air treatment 206,750 20,018,500 242.06 6.2 (82,700m2 @ £2.50) Water cooled chillers 1,520,000 (8,000kw @ £190/Kw) 9 Cost Model Tall Buildings | For Building Magazine

Cost Model Tall Buildings

Element Cost/m2 % total cost GIFA (£) cost

Protective installations 2,722,500 32.92 0.8 Wet riser installation: permanent and 455,000 temporary (65 landings @ £7,000) Sprinkler installations, complete with tanks, 2,067,500 pumps, risers and coverage to landlord areas (82,700m2 @ £25) Gas suppression in communications rooms; 100,000 protection to generator room (1 @ £100,000) Lightning protection (1 @ £100,000) 100,000

Communications, security and controls 7,288,200 88.13 2.3 installations Fire detection and fre alarm system 1,488,600 (82,700m2 @ £18) Voice alarm system (82,700m2 @ £8) 661,600 Landlord’s CNS – landlord’s mobile boosting 1,250,000 and wif coverage excluded (1 @ £1,250,000) Security/CCTV installations (1 @ £430,000) 430,000 Disabled alarm, refuge and fre telephone 150,000 installations (1 @ £150,000 Building management and energy 3,308,000 management system (82,700m2 @ £40)

Builders’ work 2,200,000 26.60 0.7 Builders’ work in connection with services 2,200,000 installations, fre stopping etc (1 @ £2,200,000)

Preliminaries and contingencies 79,818,000 965.16 24.9 Main contractor preliminaries costs and OH&P 53,358,000 approx. 22% Risk transfer at 4% and construction 26,460,000 contingency at 5%

Total shell and core (excluding demolition, 320,462,900 3,875.00 100.0 external works, external services, category-A ft out, tenant enhancement, professional fees and VAT)

10 alinea consulting LLP 90 Cannon Street London, EC4N 6HA alineacostconsulting.com