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BUILDING STUDY

AHMM remodels Broadgate for Generation Z

No1finsburyavenue by ahmm
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Allford Hall Monaghan Morris’s signature retrofit of Peter Foggo’s No 1 Finsbury Avenue has adapted the High-Tech, high-finance icon to attract a younger, less corporate tenant mix. Photography by Tim SoarRob Parrish and Gareth Gardner

A visit to Broadgate on the eve of the coronavirus lockdown was slightly eerie. The complex clustered around Liverpool Street station, originally developed in the 1980s, was all but deserted. There was no sign of the usual busy passage of city workers criss-crossing its central space, Finsbury Avenue Square, off which 1 Finsbury Avenue sits. 

From the present perspective in the midst of a health and gathering economic crisis, it would be easy to go overboard with predictions of radical changes to the way we will work. But, with questions being asked about the necessity for so many people to travel to city-centre offices, big signature office-block developments such as British Land’s at Broadgate will clearly be in the cross-hairs of any speculation.

When Broadgate was built, it was quite radical, even ahead of the curve. It provided a new model of high-end spec office development and was an early project by developer Stuart Lipton. Here the architecture was as important as the large floor plates, designed to attract a single large finance tenant. Big-name architects such as SOM and, for 1 Finsbury Avenue, Arup Associates, were employed. ‘Broadgate redefined property development in London,’ says Paul Monaghan, a founding director of Allford Hall Monaghan Morris (AHMM), which has been reworking the building. 

As well as the architecture, it was also Broadgate’s pedestrianised heart, furnished with public art, that was new, bringing a New York model of corporate private/public space to the City. The development was also instrumental in transforming an area bordering Shoreditch and Spitalfields, previously considered ‘City fringe’, into a desirable address for large finance houses.

The site was that of Broad Street station, once a significant 19th century London terminus next to Liverpool Street, but which by the 1970s had seen many of its suburban and outer-London services superseded by other forms of transport. With its remaining services transferred to Liverpool Street, the station closed in 1986. Work had by then long been progressing on the site and in 1984 1 Finsbury Avenue was the first building completed. The timing meant the development was perfectly placed to take advantage of London’s resurgence as a financial centre, the Thatcher government’s ‘Big Bang’ deregulation of the City of London in 1986 leading to a loads-a-money boom. 

No 1 Finsbury Avenue was designed by Peter Foggo, lead designer at Arup. Rab Bennetts was also on the design team. Unlike some of its later pink granite and marble-clad PoMo neighbours, the building still rocked a lean 1970s Hi-Tech aesthetic. Its expressed eight-storey rolled-steel frame, faced with a prominent web of diagonal bracing and brise-soleil, read like a kind of exoskeleton in the manner of the Pompidou Centre, albeit a more sober, monochrome version. Internally, a central glazed-roof atrium acted as a lightwell to illuminate the deep floorplates, with lift cores arranged off this. A pub and restaurant were incorporated at ground-floor level and a basement sports club with squash courts sat alongside copious underground car parking. 

When the building made the cover of The Architectural Review in May 1985, it was the first spec office ever to have done so. Even the heating system was bespoke, with hot water pumped through the steel window mullions. ‘You can’t imagine a spec office designed like that today,’ laughs Monaghan. 

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The qualitative ambition of the scheme paid off: Swiss bank UBS signed up as a single tenant, taking it as its London HQ. Subsequent construction of  2 and 3 Finsbury Avenue, also to Foggo’s design, completed a corral around the north-east corner of the Broadgate development, creating a new rampart-like boundary to the City, its buildings’ backs turned, to a degree, towards Shoreditch to the north. 

Over the years, the inherent flexibility of No 1’s steel frame allowed for changes to the building’s layout. Most notably, flooring was installed across the atrium at level 3 in 1997 to create a large trading room, helping to accommodate the growing needs of the bank. However, with the building requiring a comprehensive upgrade, UBS moved out in 2015, although only to the new Make-designed 5 Broadgate across the square. This was a coup for Broadgate, seeing off the threat of the bank jumping ship to Canary Wharf. 

But the arrival of Make’s block, which involved demolition of two late-1980s Arup buildings, kindled a controversy over the destruction of the original Broadgate development as a 1980s ensemble. Stuart Lipton was among the many who supported its listing. The protestations led to the Grade II listing of 1 Finsbury Avenue in 2015, but British Land argued successfully for immunity from listing for most of the rest, including 2 and 3 Finsbury Avenue; Danish practice 3XN was appointed last year to replace this section with a 32-storey tower.

No1finsburyavenue by ahmm3

Meanwhile, with Broadgate’s heyday of finance in question post-Brexit, British Land has been busy adapting the business model to attract the wider tenant mix possible with redevelopment. The changes include the ongoing reworking of a block by Hopkins, adding extra galleria-type floors of retail leading into Liverpool Street station, and the replacement of the Arup-designed 1-2 Broadgate on the south side of Finsbury Avenue Square with a 12-storey AHMM-designed block mixing offices with retail. In this context, 1 Finsbury Avenue looks set to be the last largely intact original building remaining in the Broadgate development.

British Land, ever resourceful, sought to turn the listing of the building with its remaining authentic 1980s vibe to its advantage. An Arup-designed scheme involving a major rework and addition of two floors was superseded by this much lighter-touch retrofit by AHMM – albeit one still costing £65 million. 

The ethos, according to AHMM’s typically narrative-heavy design statement, is summed up in the slogan ‘Raw is More’

The ethos, according to AHMM’s typically narrative-heavy design statement, is summed up by the slogan ‘Raw is More’. The reworked building’s parti has become a more starkly ‘naked’ retrofit frame: an aesthetic and language addressed not to finance but to the Shoreditch and Old Street roundabout tech crowd. It’s a further adaptation of the mix and ‘offer’ of Broadgate, if in essence just British Land following the money again.

The work has, of course, involved the major upgrade and replacement of elements such as lifts and toilets, while bringing the services up to grade. But, in general, Monaghan says: ‘The  key driver was for it to have a really raw quality. It didn’t need to make statements.’

No1finsburyavenue by ahmm4

The main change externally has been to give the building a more permeable, inhabited edge. Now retail units encrust the square glazed frontages on the ground floor, while the eighth has seen the opening-up of roof terraces. To an extent this move turns the previously atrium-focused building inside-out.  

A skirt of café and restaurant table areas spills out and softens the frontage to the square, and a larger terrace has been built out on the south-east corner. With a view to extending the active diurnal use of Broadgate, an Everyman cinema theatre has been secured as tenant in the north-east corner, the space for three screens cleverly carved out of the former squash courts. Car parking has been reduced to one disabled space, while bicycle storage has increased –  380 racked spaces for the building’s 3,800 potential users. This provision is accompanied by copious shower and changing facilities.  

With a second entrance opened up on Finsbury Avenue, a ‘public’ route through the building is signalled above both entrances by kinetic advertising-type hoardings, designed for a changing artwork. A new ramp, flanked by steps, leads down to the slightly sunken ground floor. 

No1finsburyavenue by ahmm5

The central atrium has been reimagined as a ‘public room’, cruciform in plan, warmed up with a timber floor. Reception and a seating area occupy the north and south arms. More commercial spaces animate its edge, with tech crowd-friendly tenants such as a gym and, bizarrely, urban axe-throwing. The centre is occupied by a vividly coloured, slightly OTT graphic sculpture-cum-café bar, designed with Studio Myerscough to create a centre of gravity to the space and draw the eye down from the two work-floor galleries above. The move creates a more horizontal focus and flow to the awkward cut-off central stump of the original atrium. 

No1finsburyavenue by ahmm7

More sense is made, too, of the floor plate division with a shift in tenant type. Two floors of co-working space – run by British Land’s own workspace brand, Storey – open out in upper tiers of the ‘public room’. Above these, the floorplates are designed to be taken by single, large, tech company tenants. The base of the upper atrium forms a flexible presentation or theatre space with bleacher seating, and is awkwardly overlooked by upper storeys. This part has attracted Mimecast, which occupies several floors.

The reworking of the building shows the usual AHMM thoroughness and chunky, graphic aesthetic. It’s a knowing strip-out-as-branding the practice has been perfecting since its Tea Building retrofit, a narrative of concept, detail and graphics it took to a new level with the faux-retrofit look of the White Collar Factory development on Old Street. 

All the steelwork, previously subjected to corporate cover-up, is exposed, showing the scars of previous adaptation with rough-cut and welded cleats, all heightened and emphasised by being painted black. It has the effect of appearing to fold the steel skeleton of the exterior inside, where it forms a graphic gridding of the interior spaces. 

All the steelwork, previously subjected to corporate cover-up, is exposed, showing the scars of previous adaptation

Highly ordered, exposed services in the ceilings are all of a piece with the aesthetics, and help to increase the sense of space within the relatively low floor heights.

The monochromatic palette is heightened by white LED lighting. In a nice touch, a grid of round lighting in the lower atrium, which adjusts in intensity over the day, is mirrored in the upper atrium by acoustic tube baffles hanging below the skylight. In an if-it-ain’t-broke-why-fix-it vein, the original heating system running through the window mullions has been retained, but with new, energy-efficient boilers. The overall scheme has received a BREEAM Very Good rating.

No1finsburyavenue by ahmm8

Reprising the effect of the installation in the lobby space, the monochrome palette of the interior is contrasted and accentuated throughout by splashes of concentrated colour. Staircases are painted and lit in different, intensely saturated hues, like the inside of an Anish Kapoor sculpture. A softer but equally curated colour palette of tiling completes the carefully specified utilitarian-deco finish of the bathrooms, specified exclusively with chunky North American fittings. Supposedly it’s a mash-up of references to both early SOM and the suburbia served by Broad Street station. The associations are somewhat obscure but the effect is to add warmth and accents.  

No 1 Finsbury Avenue is a last bastion but also a bellwether of change for Broadgate. As a scheme, it testifies to AHMM’s design skills and respect for the architecture and to the flexibility of the original design. AHMM has adapted a monument to 1980s office culture to a new world of work. The question is: what will the new world of work now look like? Might this new incarnation itself seem to belong to a different era, post-lockdown? 

Architect’s view

The main focus of the project was to re-use and extend the life of an existing building. Elements that would normally be replaced in office redevelopments were renovated and re-used, resulting in significant cost savings and reduced life-cycle carbon emissions. 

This included retention of existing double-glazed units and 90 per cent of the central plant systems, while improving the building’s energy efficiency performance. The retention of existing services also enabled the client to offer a resilient back-up power supply to all office tenants.

The façade’s heated mullions still performed well after 35 years, achieving current Building Regulations requirements for airtightness. With the refresh of the services, the building’s EPC rating was improved from E to B. Thermal comfort and air filtration quality were improved, while new LED lighting resulted in reduced energy consumption. New sanitaryware has resulted in a 53 per cent reduction in water usage. New high-performance façades were provided at ground floor, on rooftop plant areas and at the roof terrace access. 

The key principles of WELL certification were incorporated into the design, although formal certification was not sought. 

Two large terraces have been formed at roof level and smaller terraces on a number of the office floors have been provided for amenity use where previously only maintenance access was possible. Together with informal seating at ground floor, these offer alternative informal workspaces as well as places to relax and socialise. 

Cycling is encouraged by the retrofit with the provision of 380 cycle spaces in the basement, served by a dedicated ramp.

Tom Wells, senior architect, Allford Hall Monaghan Morris

No1FinsburyAvenue by AHMM

No1FinsburyAvenue by AHMM2

No1FinsburyAvenue by AHMM3

Client’s view

We are delighted with the result and the quality of space that it provides. The building has been re-energised while retaining its iconic design. New roof terraces, the introduction of retail and leisure uses and active ground-floor frontages work with the grain of the original architecture. They add a new dynamism to the building and the spaces around it, making it more permeable and open to the City. AHMM’s successful redesign of the building has been reflected in our leasing success: all the space was let before practical completion of the works.

Nigel Webb, head of developments, British Land

No1FinsburyAvenue by AHMM4

Engineers’ view

A strategic review of existing structure and MEP plant operational life was carried out during the due diligence stage to develop an effective retention strategy. The existing structure has been retained with limited structural interventions, prioritising the specification of cement replacement in new concrete mixes to minimise materials life cycle impacts. We have challenged the convention that in a redevelopment of this type and scale the existing plant should be replaced simply on account of its age, and instead aimed at careful re-use, renovation and adaptation of 90 per cent of existing plant through clever design and ad hoc performance-enhancing interventions. 

The approach we adopted sought to balance life cycle cost, carbon emissions reduction and health and wellbeing considerations, with the objective of delivering value to both the client and the future occupiers. Example interventions include:
• Upgrade of existing air-handling equipment retrofitted with heat recovery, resulting in both CapEx and energy savings 
• Replacement of existing boilers with more efficient equipment with much lower NOx polluting emissions, with positive impact on local air quality 
• Re-purposing of existing generators to offer resilient back-up power to all office tenants.

The services strategy incorporates a number of best-practice features to meet high standards in terms of the building’s management and user environmental control, including: 
• Building management system upgrade
• Low sanitary fittings and leak detection systems
• Daylighting sensing and DALI lighting control
• Fan coil units smart control strategy and zoning to enhance thermal comfort
• Extensive energy and water metering to enable effective monitoring, reporting and use reduction during operation.

David Pearce, associate director, and Elisa Bruno, senior mechanical engineer, Arup

No1FinsburyAvenue by AHMM5

Working detail

No1finsburyavenue by ahmm6

The inherited office floor space was dated and corporate. AHMM stripped these finishes and exposed the impressive raw steel frame of the building to create generous, open-plan floorplates able to cater to modern and flexible working requirements. The cementitious spray to the beams was retained and painted black, the galvanised deck to the soffit was painted white to reflect light and maximise the apparent floor-to-ceiling height. The intumescent overspray was neatened at a consistent datum and the rusty columns were refinished in black intumescent paint. 

Fan coil units are mounted tightly within the coffers and have branches, which undulate under the primary beams to each diffuser, creating a sculptural array of exposed services. The services are mirrored around the centre of the building, forming four symmetrical quadrants visible from the atrium areas. AHMM’s specified strip track system lighting can be found underneath the ducts and diffusers. Usually deployed in factories, it was adapted to office use by using a different diffuser. The result is a cost-effective but impressive arrangement of slim, black fittings with an industrial aesthetic underneath the exposed services. 

New base-build elements, such as balustrades, ceilings and atrium glazing, are detailed as precision black metal elements, which hover off and contrast with the rawness of the existing frame. The lower atrium is finished with rough-sawn timber flooring throughout, translucent glazing planks, mesh balustrades and striking lighting arrays to emphasise the use of this new public room as both office reception and street.

Tom Wells, senior architect, Allford Hall Monaghan Morris

No1FinsburyAvenue by AHMM6

Project data  

Start on site July 2017
Completion October 2019
Gross internal floor area 36,538m²
Construction cost £65 million
Construction cost per m² £1,779
Architect Allford Hall Monaghan Morris
Client Joint venture between British Land and GIC
Structural engineer Arup
MEP consultant Arup
Quantity surveyor Equals
Project manager M3 Consulting
Principal designer AHMM
Building control City of London Building Control
Construction manager Sir Robert McAlpine
CAD software used Autodesk Revit
Acoustic consultant Arup
Fire consultant Arup
Townscape heritage Robert Tavernor
Façade consultant Arup
Sustainability consultant Arup
Planning consultant DP9
Access consultant David Bonnett Associates
Maintenance and access consultant Reef
Retail fit-out The Faces

Performance data 

Heating and hot water load 38.43 kWh/m²/yr
Total energy load 
• 121.16 kWh/m²/yr  regulated + unregulated
• 76.23 kWh/m²/yr  regulated
• 44.93 kWh/m²/yr  unregulated
Carbon emissions (all) 28.2 kgCO2/m²
Annual mains water consumption
• 4.70m³/person/yr (including fixed uses)
• 5.12m³/person/yr (including fixed uses such as cleaning, food preparation, vessel filling)
Airtightness at 50Pa 7.24 m³/hr/m² (A whole building airtightness test has not been undertaken. However, a sample of the existing façade on level 7 has been tested and achieved 7.24 m³/hr/m² @50Pa, so a value between 7 and 10m³/hr/m² could be a reasonable estimation. 25m³/hr/m² is the value assumed in energy calculations as per NCM methodology.)
Overall thermal bridging heat transfer coefficient (Y-value) 0.38 W/m²K
Overall area-weighted U-value 0.84 W/m²K
Embodied/whole-life carbon 11.55 kgCO2 eq/m²
Predicted design life 15 years

 

  • 2 Comments

Readers' comments (2)

  • It's good to see 1 Finsbury Avenue rejuvenated. One point to correct; The Finsbury Avenue Development was not part of Broadgate. That came later, following a competition in 1984-5 initiated by British Rail Property, which was won by substantially the same team of Arup Associates, Stuart Lipton et al. It was not until the last phases of Broadgate in the late '80s that other architects like SOM were brought in.

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  • Quite right Rab, as I was about to say! And also "Subsequent construction of  2 and 3 Finsbury Avenue [...] completed a corral around the north-WEST corner of the Broadgate development". Neither was actually in the City of London at the time - only in 1994 when the boundaries were revised did Broadgate and Finsbury Ave come in.

    The 1998 remodelling also included extensive provision for large-scale IT: the installation of a new electrical substation, additional risers for cabling and pipes, upgraded air handling plant, a new, deeper raised floor to house the necessary equipment for this, shallower suspended ceiling and new light fittings were also put in, which incorporated air extraction.

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