5 Aldermanbury Square
London

Building Team

• CLIENT: SCOTTISH WIDOWS
• INVESTOR/DEVELOPER: SCOTTISH WIDOWS
• DEVELOPMENT MANAGER: HANOVER CUBE
• ARCHITECT: ERIC PARRY ARCHITECTS
• INTERIOR DESIGNER: ERIC PARRY ARCHITECTS
• STRUCTURAL ENGINEER: RAMBOLL WHITBYBIRD
• SERVICES ENGINEER: HILSON MORAN PARTNERSHIP
• QUANTITY SURVEYOR: NORTHCROFT
• BRIEF CONSULTANT: BH2
• CONTRACTOR: BOVIS

Building Data

• COMPLETED: SEPTEMBER 2007
• NET: 25,668 m²
• GROSS: 35,171 m²
• EFFICIENCY: 73%
• FLOORS: 19
• COST: £73,360,000

As is typical, one of the requirements of this project was to create a building with clear, uncluttered floor plates, and so the architects minimised structural intrusion by pushing the key structural elements outwards. Corten steel box columns were filled with concrete to create fire-protected, maintenance-free units that require no inspection or complication of the facade (and paint coatings are not required for a fire rating). The glazing units, extending over two storeys, are set back into the depth of these immense columns, allowing the structure itself to provide a rigorous, three-dimensional composition and a degree of shading. The columns, which are relatively small in profile, are clad in shot-peened 3 mm thick stainless steel panels, which provide a lightly reflective and very clean wrapping to the structure. Steel brise soleils are provided at intermediate floor levels.

This structural approach was part of a revision of the original intention. During design review, the structural zone required for each floor was reduced by 150 mm, allowing the building to gain an extra storey without becoming taller. The typical floor plate is interrupted by a lift and service core (accommodating eight elevators and a service lift), an escape stair and just four internal columns.

Just as remarkable as the structure/cladding solution was the fact that Bovis managed to

Internally, The Building Is Planned On A 1,500 Mm Module. A Typical Floorplate Is 34.5 M Wide And 59 M Long In The Longest Wing. The Facade To Core Dimension Is Typically 10.5 m.

© Nicholas Kane

Built From A Steel Frame With Composite Concrete Floor Slabs; External Steel Columns Are Constructed In Corten And Filled With Concrete To Provide High Performance In Fire.

© Eric Parry Architects

The Depth Of The Steel And Concrete Frame Of The Building Provides Shading And An Animated Facade. The Frame Rises In Two-Storey Units; Brise Soleils Are Fitted At Alternate Levels.

© Timothy Soar

complete the building on time in spite of the fact that Schmidlin AG, the German cladding subcontractor, went into receivership during the build programme. Such a feat was possible because of the immense amount of preparation, testing and quality control procedures that occurred in advance of construction. At an early stage, detailed discussions were held with three facade contractors, and full-sized mock-ups were constructed prior to making a final selection. By the time of the tender the facade package team had detailed knowledge of the particular issues presented by the stainless steel facade, and how they could be addressed on site. This included visits to key parts of the supply chain and frequent quality control checks at the main production plant. There was stringent checking of the finish and dimensional tolerance on site prior to installation.

Ground-Floor Plan Of The Office Building, Which Includes A Generous Public Space.

© Eric Parry Architects

‘Developers can throw money at a project and still end up with something average,’ said a BCO judging panel. ‘However, at £73 m, 5 Aldermanbury Square was certainly not cheap but value for money shines through. It is bold and brave but also incredibly elegant, achieving Scottish Widows’ wish to set a new benchmark for this part of London. The design has a timeless quality that will age well without excessive maintenance demands.’

The building also benefitted from a sophisticated fire and evacuation modelling strategy, as well as extensive discussion with the London Fire Brigade and local authority surveyors. Analysis showed that, even if the building was occupied at a density of one person per 7 m², it could be successfully evacuated in stages. This study was useful in that it proved that the building could accommodate tenants who require financial dealing rooms, while open stairwells could be opened up between floors without compromising the overall fire strategy or having to provide protected shafts. This dramatically enhances the ability of tenants to operate over multiple floors.

It is also worth recording that 5 Aldermanbury Square has gone a long way to improving what was a botched corner of the City of London. ‘The triple-height public space under the building replaces the dysfunctional 1960s urban plan which included a taxi rat-run, elevated walkways and miserable architecture to match,’ said the architects. A newly landscaped public square and better pedestrian links to surrounding streets (including high-level access to the Barbican) has rather rehabilitated this historic zone. That the building has been designed to weather elegantly (through, for example, a combination of high-quality materials, a careful consideration of water run-off, the avoidance of additional layers of glass to minimise the cleaning regime and straightforward, elegant design) provides a further enhancement to the streetscape. ‘The brief from the client was for a building that would improve with age and look as good in 50 years as it does now, without an onerous maintenance regime,’ said the architects.

BBC Mailbox
Birmingham

Building Team

• CLIENT: BBC PROPERTY
• ARCHITECT: BDP
• INVESTMENT/PROPERTY COMPANY: BBC PROPERTY
• INTERIOR DESIGN: BDP (WITH IDEA)
• STRUCTURAL ENGINEER: BDP
• SERVICES ENGINEER: BDP
• QUANTITY SURVEYOR: FROST ASSOCIATES
• PROJECT MANAGER: DEARLE AND HENDERSON
• CONTRACTOR: INTERIOR EXTERIOR (ISG) PLC

Building Data

• COMPLETED: MAY 2004
• NET: 8,111 m²
• GROSS: 11,527 m²
• EFFICIENCY: 70%
• FLOORS: 4
• COST: £45,000,000 TO CAT B

The BBC demesne within the Mailbox comprises two double-height spaces – one of 72 × 78 m; the other about a quarter of this size, which sits beneath the main space. Into these volumes had to be crammed offices, open-plan teamwork areas, technical facilities, recording studios and public galleries. Flexibility was paramount; hotdesking is widely used and meeting rooms contain movable partitions and furniture on wheels. The entire ethos is for an environment that can be quickly adapted to the needs of changing teams and broadcast priorities. ‘In essence, the modern office is no longer just desks and tables,’ wrote Paresh Solanki, executive director/producer at BBC Birmingham. ‘It is much more of a complete experience with the latest technological tools, better people–machine–office interfaces and a friendly creative environment where staff feel inspired and safe.’

So where to put it all? The addition of a series of mezzanines, referred to as ‘gondolas’, makes up the shortfall in space requirements, but this had to be done carefully. The double-height spaces of the Mailbox are only around 5 m high, so BDP had to exercise considerable ingenuity in adding these structures – reasonable head heights had to be preserved while delivering cabling beneath raised floors. Furthermore, the open-plan spaces could not become cluttered with extra columns, which might compromise the spatial flexibility which was part of the rationale for relocating in the first place.

The Wave Form Of The Ceiling Follows The Pattern Of The Building’s Beams. The ‘Gondola’ Floors, With A Typical Depth Of 10.5 M, Manage To Preserve A Reasonable Floor-To-Ceiling Height: 2,250 Mm Spaces Are Provided Beneath The Floors; Spaces Of 2,260–2,700 mm Are Achieved Above Them.

© David Barbour

This Project, Which Saw The Bbc’S Midlands Operation Move From Its Pebble Mill Building To Birmingham’S Mailbox Development, Required The Provision Of Extra Space By Suspending New Floors From The Original Structure.

© David Barbour

The architects eventually suspended slimline steel structures from the heads of the steel columns of the building itself; these structures were configured as aerofoils, where tapered edges reduced the visual impact of these elements. The gondolas are used to deliver fresh air, power and data into the work spaces, while low-energy chilled panels affixed to their underside provide cooling to the spaces below.

A waveform ceiling also helps to maximise head-heights. The Mailbox is constructed of steel columns and beams, with floor slabs in precast coffered concrete. The architects installed a ceiling that wraps around the structural bays, dropping down as ‘troughs’ where steelwork is located, but providing extra height at regular intervals. This ceiling system also conceals low-energy passive chilled beams and other services. The complete assembly provides a ceiling height of 2,250 mm under the mezzanines, and 2,260 mm over them (rising to 2,700 mm in the rise of the waveform ceilings).

In spite of the exacting acoustic requirements of the building, loading constraints meant that the new state-of-the-art studios had to be constructed from lightweight materials. Modular perforated metal and timber cladding panels, in cherry, conceal services and acoustic absorbers while providing a high-quality finish. Particular attention had also to be paid to matters including duct layouts, air speeds, plant noise, anti-vibration mounts and door construction.

Cross Section Through A Mezzanine Unit. These ‘Gondolas’, Which Are Steel Structures Suspended From The Building’S Columns, Contain Power And Air Supply Ducts.

© BDP

‘The standard of fit-out is very high; all elements display imagination, but also great discipline. It could have been frightful: instead it is great,’ said BCO judges in 2005 before awarding this project the ‘Best of the Best’ Award. ‘The building is full of dynamism and light. A sense of openness is created by vast internal spaces, carried outwards by cutting huge windows across the front of the shell. Extra space was conjured from thin air by floating mezzanine “gondolas” within the hangar-like shell. Over a narrow band, they reduce ceilings below BCO standards but this has been overcome on the upper level with a clever ‘wavy’ ceiling making the most of space and hiding existing structure and environment-friendly chilled beams.’

HM Treasury
London

Building Team

• PROJECT SPONSOR/END USER: HM TREASURY
• PROJECT SPONSOR�S REPRESENTATIVE: GARDINER & THEOBALD MANAGEMENT SERVICES
• CLIENT CONSORTIUM: EXCHEQUER PARTNERSHIP (STANHOPE PLC, BOVIS LEND LEASE LTD, CHESTERTON INTERNATIONAL PLC)
• ARCHITECT: FOSTER + PARTNERS
• HERITAGE/CONSERVATION ARCHITECT: FEILDEN & MAWSON
• SPACE PLANNING: DEGW
• STRUCTURAL ENGINEER: WATERMAN PARTNERSHIP
• SERVICES ENGINEER: JAROS BAUM & BOLLES
• COST CONSULTANT: FAITHFUL & GOULD
• SERVICES COST CONSULTANT: MOTT GREEN & WALL
• CONTRACTOR: BOVIS LEND LEASE

Building Data

• COMPLETED: JULY 2002
• NET: 31,651 m²
• GROSS: 36,138 m²
• EFFICIENCY: 87.6%
• FLOORS: 9 (7 + 2 BASEMENTS)
• COST: £90,172,751

Upgrading Her Majesty’s Treasury Building, listed Grade II*, was a job that involved a considerable amount of vision from both client and design/construction team. The original 18th-century building in Whitehall was highly cellular, and circulation was compromised by its many fireplaces and light wells. The Treasury, which formed a PFI consortium to manage the project, wanted to retain the building but open it up and thoroughly modernise it. This entailed removing 7.7 miles of internal brick walls, strengthening the remaining walls, floors and windows, and roofing over eight lightwells. The removal of four major staircases, toilet blocks and chimneys means that this major refurbishment of the western half of the building, completed in August 2002, has provided the Treasury with 25% more space. The building now accommodates 1,200 staff in space formerly occupied by just 850 people. For the first time in half a century, Treasury employees work in a single building. It has even been awarded a BREEAM rating of ‘excellent’.

The original building, characterised by separate office spaces located off long and unprepossessing corridors, was largely of masonry construction, with load-bearing brick walls supporting floors of steel joists and clinker concrete. Where load-bearing walls have been removed, steel frames have been introduced. More than half the office floors are now open-plan, while the conversion of lightwells into atria has created communal areas and space for a new reception (fitted with four new lifts). Atria are equipped with louvres which react to external weather conditions and assist with natural ventilation. The ground floor

The Refurbishment of Hm Treasury has Added 25% Of Useable Space To The Building, Providing Facilities For 1,200 Staff Where 850 Were Employed Previously.

© Nigel Young / Foster + Partners

now contains a 200-seat auditorium, as well as meeting and training rooms, a library, restaurant and recreational facilities.

Designed For An Occupational Density Of 1:12 M², 60% Of The Refurbished Building Is Naturally Ventilated. The Project Received A Breeam Rating Of ‘Excellent’. Lighting Levels Reach 350 Lux.

© Nigel Young / Foster + Partners

Purely for financial reasons, this project had to be ambitious. Studies showed that, without reinventing the building, updating services would have cost £50 million, so it made sense to invest in the site properly and completely rethink the way the building worked. Views have been improved and energy reduced by increasing the amount of daylight entering the building – in fact, even cleaning the lightwells and courtyards has caused more daylight to be reflected into the office spaces. Significantly, the large central courtyard has not been glazed over – this remains as an external, landscaped amenity.

‘As the building is also naturally ventilated, it is irresistible to say that, both figuratively and literally, the new Treasury Building represents a breath of fresh air blowing through the corridors of power – a transformation from labyrinth to leitmotif for transparency,’ said the judges’ report.

One Of The Key Moves Was Cleaning The Light Wells And Bringing Them Inside To Provide Reception And Circulation Spaces. These Light Wells Have Been Fitted With Transparent Roofs With Opening Louvres.

© Nigel Young / Foster + Partners

Typical Floorplan. The Removal Of Masonry Walls Has Created More Open Space, While Light Wells Have Been Roofed Over And Brought Inside.

© Foster + Partners

Royal Bank of Scotland Headquarters
Edinburgh

Building Team

• PROJECT CLIENT/OWNER: THE ROYAL BANK OF SCOTLAND GROUP
• INVESTOR/DEVELOPER: THE ROYAL BANK OF SCOTLAND
• ARCHITECT/INTERIOR DESIGNER: MICHAEL LAIRD ARCHITECTS/RHWL
• SERVICES ENGINEER /STRUCTURAL ENGINEER: WSP
• QUANTITY SURVEYOR: DOIG & SMITH
• PROJECT MANAGER: MACE
• BRIEF CONSULTANT: MICHAEL LAIRD ARCHITECTS
• CONTRACTOR: MACE
• ANCILLARY BUILDINGS CONSULTING ENGINEERS: SKM ANTHONY HUNT/FULCRUM

Building Data

• COMPLETED: JULY 2005
• NET: 33,850 m²
• GROSS: 38,970 m²
• EFFICIENCY: 87%
• FLOORS: 4
• COST: £199,820,000 TO CAT B

The main office building – in fact a cluster of seven buildings grouped around an internal street – sits at the centre of the site; Gogarburn House, a Grade B listed dwelling, has been converted into a staff club; and there is also a conference centre, a nursery and a business school (built with support from Harvard University) on this woodland campus. Time and budgetary constraints put prefabrication of the main building envelope high on the agenda; WCs, too, were constructed off-site as modules.

At the project’s concept stage, as many as 13 structural options were examined for the main office block in order to find the optimum solution across a range of factors including cost, floor heights, ceiling finish and quality, schedule, floor plate flexibility, sustainability and the complexity of service/facade integration. The team settled on post-tensioned floor slabs supported by precast concrete columns on a 9 × 9 m grid. Off-site manufacture reduced on-site waste and labour, and maximised quality, while the post-tensioned slabs increased the span while reducing the thickness of the floor plates. The relatively thin slabs consequently reduced the height of the building, which created further spin-offs: savings on external cladding materials, and less embodied energy. Furthermore, the structure is said to be lighter than the equivalent in situ

At The Heart Of The Main Building Is A 280 M Long Internal Street, Onto Which Separate ‘Business Houses’ Connect. The Street Is An Integrated Part Of The Working Environment.

© Keith Hunter

Royal Bank Of Scotland. This Project, In Gogarburn, Edinburgh, Was A 100 Acre Development Containing 74,484 M² Of Buildings (Gross). The Development Contains 33,850 M² Of Office Space (Net)

© Keith Hunter

Site Plan. The Main Building, In The Centre Of The Image, Is Part Of A Wider, Wooded Campus.

© Michael Laird Architects

concrete frame, while the flat soffits simplified formwork and allowed complete flexibility on the distribution of services. The design also benefitted from research conducted by engineers at WSP, who reappraised seminal work done in the 1960s on floor loading for offices by Mitchell and Woodgate. ‘The reappraisal supports the view that over-design has been prevalent, in spite of the efforts of the BCO, and shows that 3.5 kN/m² (including partitions) is perfectly satisfactory for upper floors,’ wrote Michael Laird Architects in their award submission in 2006.

The building was completed in July 2005 (after 2½ years on site), and the client is happy that its new estate makes for a better life–work balance. ‘There is a unanimous feeling that the building not only provides an enviable working environment but also makes the working day much easier,’ wrote Barry Varcoe, RBS’s group property director. It’s not hard to see why: the 280 m-long street running through the main building contains shops, cafes, a restaurant, a Tesco Express and other ‘high street’ services, while a medical and dental centre form part of a wide mix of other facilities on the site. Views from the 18 m deep office floor plates reveal woodland vistas, while a huge variety of spaces have been provided for staff to meet, relax, collaborate or profitably get away from the desk without leaving the building. Varcoe was even convinced that staff were sending fewer emails internally, preferring to converse face to face: ‘It instinctively eels like a much smarter and more efficient way of working.’

Michael Laird Architects Were Initially Appointed By Rbs To Consider The Feasability Of Redeveloping A 1960S City Centre Building For The Bank, But The Project Was Abandoned When A Property Deal Could Not Be Finalised. Construction And Security Risks Also Counted Against That Central Edinburgh Option.

© Keith Hunter

BCO judges, too, were impressed: ‘From the superb entrance, to the street, the office floors and the boardroom, every space, every detail shows consummate skill stemming from the quality of the brief and the designers’ excellence. Despite the huge size, it does not dwarf people … The whole package is great value for money.’

The building has been awarded a BREEAM rating of ‘excellent’.

180 Great Portland Street
London

Building Team

• CLIENT: GREAT WIGMORE PARTNERSHIP
• OWNER/DEVELOPER: GREAT PORTLAND ESTATES
• ARCHITECT: LIFSCHUTZ DAVIDSON SANDILANDS
• INTERIOR DESIGNER: LIFSCHUTZ DAVIDSON SANDILANDS
• STRUCTURAL ENGINEER: WSP
• SERVICES ENGINEER: CUNDALL JOHNSTON AND PARTNERS
• QUANTITY SURVEYOR: DAVIS LANGDON
• PROJECT MANAGER: BURO FOUR
• CONTRACTOR: ISG INTERIOREXTERIOR

Building Data

• COMPLETED: MARCH 2007
• NET: 7,500 m2
• GROSS: 11,879 m2
• EFFICIENCY: 63%
• FLOORS: 6
• COST: £20,402,777

The programme for the building was the reverse of the general trend, which tends to convert elderly buildings into residential units; here, a residential building was transformed into open-plan office accommodation. The building had, in fact, been used as offices for many years, but these were of poor quality and the property was characterised by its maze of rooms and corridors (and fireplaces). The presence of three ground-floor retailers with long leases, and therefore the right to continue operating during building works, made the job trickier still. The architect and engineer’s solution was innovative, to say the least.

Two new structural steel cores were inserted into existing central lightwells to provide lateral stability from new raft foundations. Once the building was braced, vertical openings were cut through five storeys of masonry wall, and steel stanchions threaded through from above, providing a new superstructure. Beams were then bolted to the new columns, on either side of the walls and immediately above the floors; these castellated beams were then attached to the Edwardian steel joists embedded in the clinker concrete floors below. Finally, the masonry walls could be demolished and a raised floor constructed over the Edwardian original. A third core was then

180 Great Portland Street. This Reinvention Of The Building Was Not A Facade Retention Exercise. Just 2,000 Tonnes Of Masonry Was Removed From The Site, Replaced By 600 Tonnes Of Steel.

© Chris Gascoigne/VIEW

1 Existing Structure

LOAD BEARING MASONRY WALLS CAST IRON FILLER JOISTS CLINKER CONCRETE

2 Stage 1 - Column Integration

NEW 5 STOREY HEIGHT STEEL STANCHIONS THREADED THROUGH POCKETS IN EXISTING STRUCTURE.

3 Stage 2 - Spine Beams

NEW SPINE BEAMS BOLTED TO STANCHIONS EITHER SIDE OF EXISTING MASONRY SPINE WALL.

EXISTING FILLER JOISTS SLUNG FROM UNDERSIDE OF NEW SPINE BEAMS.

EXISTING MASONRY SPINE WALL DEMOLISHED.

RESIDUAL HOLES IN SLAB BACKFILLED WITH INSITU CONCRETE.

4 Stage 3 - Hvac Plenum

NEW PLYWOOD DECK PACKED OFF EXISTING CAST IRON FILLER JOISTS TO PROVIDE LEVEL SUBSTRATE AND SEAL EXISTING FLOOR CONTRUCTION.

FIRE RATED PLASTERBOARD CASING APPLIED TO EACH STANCHION.

INTUMESCENT PAINT SPRAYED ON SPINE BEAMS.

FULLY STRINGERED RAISED FLOOR SUPPORT FRAME PREVENTS PLENUM AIR LOSS AT FLOOR TILE JUNCTIONS.

SUPPLY / EXTRACT PLENUM SEPARATION BARRIERS INSTALLED TO SUIT BASE INSTALLATION AIR PATHS.

5 Stage 4 - Raised Floor Installation

RAISED FLOOR TILE INSTALLATION.

HIROSS ‘FANTILE’ GRILLE INSTALLATION (INCLUSIVE OF ELECTRIC FAN AND HEATING ELEMENT).

RETURN AIR GRILLES INSTALLED.

Step-By-Step Illustration Of The Structure And Mechanical Services Strategy. Columns Were Placed Inside The Exisiting Walls, And Floor Joists Fixed To New Spine Beams. Masonary Walls Were The Demolished.

© Lifshutz Davidson Sandilands

inserted into a further lightwell, over a ground-floor sitting tenant; this core was suspended from a pair of 20 m long, 1.6 m deep, steel girders at roof level, allowing the new vertical stanchions to take up the load. Once completed, the building’s large floors became cleared of obstructions, other than the line of columns which replaced the spine walls. Moreover, this intervention was achieved with little loss of floor-to-ceiling heights; previously, air-conditioning ducts were located at ceiling level, but these could be removed as air-con and heating utilities were located within the 375 mm-deep floor plenum. A 60 mm ceiling void was created to accommodate fully recessed lighting. Loss of height varies from floor to floor: the fifth floor has lost just 10 mm, while the second storey is 70 mm short of its original height. However, floors three and four have gained in height (30 and 40 mm respectively).

The result was that only 2,000 tonnes of masonry was removed from site during building works (replaced by 600 tonnes of steel). If the architects had embarked on a standard facade retention project, that would have meant the removal of 6,500 tonnes of waste. This technique and resolution impressed the BCO judges when they made their visit in 2008: ‘This shows that innovation does not have to involve widgets, gadgets and go-faster stripes,’ they said. ‘It just requires clever ideas put together in a thoughtful way … Our primary focus should be on existing stock, and innovation must go beyond techniques such as insulation and natural ventilation to address the energy and materials embodied within buildings.’ Such a daring structural solution had further spinoff benefits: it reduced the amount of dust, dirt and noise which would have been generated, and allowed a faster build programme than almost total demolition. It also allowed the tenants on the ground floor to continue operating, which would obviously have been an impossibility through a standard facade retention approach. It was a delicate construction job though, helped by the erection of London’s largest temporary roof, covering over half an acre.

The design team was commissioned in February 2003 and planning consent was granted the following December. Construction began in May 2005 and practical completion was achieved in December 2006. Fit-out works continued to March the following year. The reinvention of this fine 11,879 m² Bath and Portland stone-clad building was achieved for a cost of £14.82 per m². The building now has 15% more space than it did previously.

‘This former Edwardian residential block, with its cramped cellular spaces, is a classic example of how to think outside the box,’ said BCO judges. ‘As buildings become more energy efficient, this focus on embodied energy will become more important. The immense savings in materials has given the building flexibility and a new lease of life while maintaining many BCO specification requirements. It shows that sustainability does not need to be visible when using careful architectural and structural techniques to regenerate buildings without paying a high price.’

The Flexible, Open-Plan Office Accommodation Installed Within This Edwardian Building Has Improved The Original Net:Gross Ratio By 15%.

© Chris Gascoigne / VIEW