EVOLUTION NOT REVOLUTION
Reiach and Hall has successfully introduced a modern office building into the sensitive context of the Old Town in Edinburgh
For the Edinburgh practice of Reiach and Hall, working on projects in Scotland means being 'acutely aware of their unique location as a generator of ideas'. The ongoing debate about 'Scottishness' in architecture has, of course, refocused attention on the dialogue between tradition and innovation, history and modernity, the local and the universal.
This is a debate that has been conducted with some vigour in Edinburgh over a number of decades.
In the late 1960s, the boldly horizontal lines of RMJM's headquarters for Lothian Regional Council (now used by the Scottish Parliament) crashed through the scale and established grain of the Lawnmarket, one of the most picturesque streets in the Old Town. The practice of Basil Spence, Glover & Ferguson demonstrated an imaginative take on tradition at 79-121 Canongate, completed the same year. But the planners' preference in more recent years, in reaction to past mistakes presumably, has been for a more literal traditionalism, verging on pure pastiche.
The designation of the core of the Scottish capital as a World Heritage Site has further increased the pressure for a contextual approach to new development. Ian Begg's Crowne Plaza Hotel on the Royal Mile, completed a decade ago, demonstrates one way of responding to context: clothing a bulky modern structure in fake historic details.
Reiach and Hall's Westport office development (the street is West Port) makes a very different response to context, though it lies just inside the area of the World Heritage Site. The drawing of the boundary at this point is hardly surprising when you look at its near-neighbour, Argyle House; a vast and truly atrocious government office building of the '60s, which may soon, fortunately, bite the dust. The land, at the junction of West Port and Lady Lawson Street, just east of the Grassmarket, was previously owned by Edinburgh College of Art.
The college's buildings, mostly of the 1900s by JM Dick Peddie - 'pleasant to use, but not to gaze upon', as Charles McKean describes them - closely abut the site. Access to the college from Lady Lawson Street had to be designed into the scheme.
The Old Town is a tight mesh of streets and closes developed in a 'fishbone' pattern along a dramatic ridge, with the castle at its highest point. It is a place of striking and often unexpected views - this is a city where roofscapes really do count. The Reiach and Hall team, led by director Neil Gillespie, with Lyle Chrystie as project architect, had to address the problem of a steeply sloping site with all the associated challenges of creating practical floorplates and legible circulation zones, and making an appropriate contribution to a historic streetscape.
The client for Westport, Dr Ali Afshar of AMA (New Town), has subsequently commissioned Reiach and Hall for several residential developments, but for this, his first office scheme, a number of practices, including Page and Park and Benson & Forsyth, were considered. Reiach and Hall was appointed in 1999. The brief was for high-quality specification office space aimed at professional clients.
The building has been designed for a single tenant or multiple letting.
The architects of Argyle House took a straightforward approach to their site, hacking it away to create a level base for their building, shoehorned into the city, with lower office floors that are effectively at basement level and look onto blank walls. In contrast, the architects of the 21st century work with the grain of the city.On West Port, Reiach and Hall sought to echo the rhythm of the existing historic street facades by breaking down the frontage of the new development into three distinct elements, separated by circulation spaces. 'The facade is a big issue in Edinburgh, ' says Gillespie, 'though style was never an issue with the planners on this project. Materials and, above all, scale were the key points for discussion.'
The key to the diagram is the location of the principal service and circulation core, extending north-south across the site and forming an axis on which the composition is articulated. Stairs, lifts and WCs are concentrated in this zone. Heating and ventilation equipment (a displacement system has been used) is concentrated into a basement plant room with a boiler and chiller at roof level where - set in glazed enclosures - they read as interesting, rather than ungainly, additions to the skyline. A second core was initially planned but this was cut back (as part of an overall trimming of the scheme) to a single staircase forming the second element of punctuation on the West Port facade.
The plan of the building represents a reinterpretation of the traditional Old Town pattern of closes at right angles to the street.
The insertion of a great void within the circulation/services core facilitates vertical and horizontal views up and across the building and brings light into its heart. However it is occupied, this building will never become a series of rigid compartments, yet in terms of gross-to-net space there is nothing extravagant about the development. It is the sense of connectivity that makes it seem more generous than it actually is. (Quite lavish finishes, including travertine and polished marble - perhaps rather too much of the latter in the reception area - admittedly help. ) On one level, the office spaces are quite conventional. The expression of the structural grid - a welcome alternative to conventional suspended ceilings - is significant in giving these spaces a special character. Service ducts are neatly contained within ranks of timber doors - another example of the attention to detail and craftsmanship seen throughout the building.
None of the floor plans are repeated across the five levels. In effect, there are three rectangles of space, divided by the two circulation zones. At fourth-floor level, the offices on the east side of the building step back to provide for an external terrace. The top floor is cut back on this side to allow for a sizeable open deck, with terrific views to the castle and Royal Mile. The occupants of the western wedge of offices have less spectacular views, though the creation of a glazed 'prow' at the angle of the two streets provides a spot to contemplate the passing life of the city.
(This is a developing quarter, where style and sleaze coexist. ) The dialogue with planners about the external look of the building produced facades that are more solid than the architect initially intended. The circulation cores were intended to be fully glazed but have now been largely clad in the Northumbrian stone extensively used on the exterior of the building. (Precast concrete is used on the rear, car park, facades. ) The street facades are distinguished by a glazing pattern that sets windows flush to the masonry; potentially a device that makes for a bland look. The use of external sun screens, some of which fold back while others slide, adds visual interest, though it remains to be seen how effective these will be.
They do not seem designed to provide easy environmental control for the building's users, and this is seen as a low-energy project.
The Westport development clearly benefited from the involvement of a client prepared to give that vital extra infusion of commitment and funding, producing results that are well above average for spec office developments in a city where rentals are half those in prime London locations.
If this sounds like a verdict of 'good ordinary', so be it. Edinburgh's Old Town is the last place where extravagant gestures are needed, at least from commercial developers - Miralles' Parliament is set to infuse contemporary drama into the historic scene.
Edinburgh bears the scars of would-be monumentalists of the recent past, a tendency personified by the ponderous bulk of Campbell & Arnott's Saltire Court (completed in 1991). In contrast, Reiach and Hall has demonstrated that the Old Town can accommodate modern workplaces and modern architecture that does not compromise but adds to the continuum of history and development in this remarkable city.
The structural form has been dictated by two primary objectives. First, the proposed environmental strategy, which required the mass of the building to be exposed; and second, the architectural intent for the cores, where the vertical elements of the structure are eroded to bring in shafts of light. In situ concrete is the appropriate material for such manipulation of surfaces; equally it is an appropriate form of construction for long-span floor plates.
The floor plates comprise 550mm-deep ribbed slabs arranged on a 1,500mm grid. Although the confined nature of the site, with minimal offloading facilities, precluded the use of precast beams or table-form shuttering to provide a truly exposed concrete finish, limited skim plaster to the lower ribs produced the sharpness of detail sought architecturally.
The need to optimise the floor area in the irregularly shaped, sloping site led to the use of a temporary, contiguous mini-pile ground-retention system, installed as little as 500mm from the adjacent art college studio.
A pile capping beam was temporarily rock-anchored out with the site and destressed after completion of the structure. Permanent ground and water retention were provided by retaining walls cast directly against the piled wall, minimising shuttering. An internal drained cavity membrane, carried down the walls and below the ground slab to field drains, completed the groundwater protection.
In situ concrete was also the appropriate material for the geometrically complex stone-clad facade frame that supports the movable louvres. While the independent frame supports gravity loading, articulation of horizontal connections between it and the long-span floors was a key issue. Likewise, the creation of cantilevers and erosion of shear walls at a variety of levels were all simplified by the flexibility of the in situ concrete form.
John Robson, Kirkman + Bradford SKM
The approach developed with Reiach and Hall Architects was to design an office building that offered a mixed mode form of environmental control, as opposed to full close-control air conditioning. These mechanical systems use less energy, are less expensive to install and operate and offer an alternative aesthetic to the standard steel frame with suspended ceiling approach.
An earlier building we designed with Reiach and Hall, the Beacon in Glasgow, is similar in concept. We monitored the thermal and energy performance of this building over a number of years, and its success informed the design applied to Westport.
The heating to the office areas is provided by perimeter trench heating, installed at 1,500mm intervals. Local thermostatic valves offer local control.
The mixed mode approach to environmental control is influenced by the amount of solar gain entering from glazed elevations and the area of exposed concrete in the office areas. This demands close liaison with the architect and structural engineer to ensure the scheme design accommodates the multiple requirements. Thermal computer simulations ran through alternative forms of solar protection and concrete coffers to appraise the level of over-heating. The building is designed to the BCO specification of an internal summertime temperature of 24degreesC for 95 per cent of the occupied hours.
The offices are served by a single air handling unit located under the car park.
Fresh air is tempered before being delivered into the 300mm clear floor void, which acts as an air plenum. Local variable air volume boxes control the amount of supply air per office suite. This supply air enters the office suite via movable circular grilles. Air is extracted at high level through the perforated ceiling tiles to high-level ducts. Research by Oxford Brookes University indicates that, under test conditions, more than 85 per cent of the cooling effect of an exposed soffit can be obtained with a thin perforated-steel ceiling.
Malcolm Tait, KJ Tait Engineers
Hall and Reiach and Hall www. reiachandhall. co. uk
Thomas & Adamson www. thomasandadamson. com
Kirkman + Bradford SKM www. skmconsulting. com
KJ Tait Engineers www. kjtait. com
TENDER DATE April 2001
START ON SITE DATE May 2001
CONTRACT DURATION 76 weeks
GROSS INTERNAL FLOOR AREA 5,777m 2
PROCUREMENT Scottish Building Contract, Contractors Design Portion (May 1999 Revision)
TOTAL COST £7,650,000
CLIENT AMA (New Town)
ARCHITECT Reiach and Hall
QUANTITY SURVEYOR Thomas & Adamson
STRUCTURAL ENGINEER Kirkman + Bradford
SKM SERVICES ENGINEER KJ Tait Engineers
PLANNING SUPERVISOR Reiach and Hall Supervisors
MAIN CONTRACTOR HBG Construction Scotland
SUBCONTRACTORS AND SUPPLIERS Fire stopping R&S (Scotland); piling Keller Ground Engineering; temporary electrics Maxxiom; roofing Grainger Building Services; mosaic tiling A De Cecco; external works John Meiklem Drainage Contractors; concrete, drainageMPB Structures; curtain walling, fire screens Charles Henshaw & Sons; lifts Otis; mechanical, plumbing ECG Group; electrical Forth Electrical Services; raised access floors Veitchi (Scotland); roof steelwork Lothian Fabricators; pend gate Fab-Tek Engineering; natural stoneWatson Stonecraft; architectural metalwork, stairs, sliding and hinged screens James Blake; joinery, partitioning JCC; suspended ceilings Allied Acoustics; decoration Robert Wilson & Son; plasterwork AJ Higgins; sundry metalwork D&R Fabrication; soft floor finishes MacGregor Flooring Company; roof landscaping Ashlea Landscaping; roof irrigation LS System