With their new headquarters for Irish state energy company ESB, Grafton Architects and O’Mahony Pike have restored the Georgian line of Dublin’s Fitzwilliam Street Lower, a bone of contention between conservationists and the client for 50 years. Appraisal by Rob Wilson. Photography by Alice Clancy and Ros Kavanagh
13 July 2022 · By Rob Wilson
Looking across to the east side of Fitzwilliam Street Lower as it recedes from the corner of Merrion Square, its brownish-pink brick façade, punctuated by a rhythm of vertical openings, blends with that of the many other grand Georgian terraces laid out from the 1750s onwards in this area of Dublin.
But most of this façade and the urban block behind it, once occupied by 16 large town houses, belongs to the newly finished headquarters for ESB, Ireland’s state-owned electricity supply board, a utility company that now operates commercially.
Designed by Grafton Architects and O’Mahony Pike, its façade is a deft riff on those of its neighbours. Its facing of sympathetic mottled brick and arched openings echo the 18th-century doorways and thresholds of moat-like lightwells to basement level. Behind this is 4,500m2 of floorspace arranged across four to eight storeys, the latter in three set-back blocks. Of this expanse, the ESB’s new HQ occupies about a half, the rest being commercial workspace with a mixed-use edge of retail to the rear.
The project’s scale and urban footprint make this the latest in an extraordinary run of large, city-scaled buildings, mostly institutional and educational, that Grafton has completed over the past 15 years. They include the Università Luigi Bocconi in Milan and the UTEC campus in Lima, the Kingston Town House and, most recently, the Marshall Building for the LSE, both in London. These are projects, often strikingly modelled, on which the practice’s ascendant international reputation has been justifiably built, leading to a crop of the world’s top architecture awards: the Pritzker Prize, RIBA Royal Gold Medal, RIBA Stirling Prize and Mies van der Rohe Award. The portfolio has seen Grafton headlining the growing prominence of Irish architecture internationally, punching well above its weight.
At first sight this chameleon-like scheme in Grafton’s home city, hiding in plain view among the Georgian brick façades, seems to be a different animal from previous projects, with their often more muscularly expressive forms. But, in fact, it’s a reprise of the same rich play between surface and carved-out volume, though here screened by the façade. Behind it, deep courts and sunken garden lightwells cut back from the street and weave through the plan.
Contextually, of course, unlike the carved-out rockface of the Lima project, which rises like a rugged cliff overlooking the sea against a busy six-lane highway, here surrounding Georgian architecture is the gentler yet more proscriptive determinant. All the more so because, after the original 2010 competition for the scheme, councillors inserted a clause into the City Development Plan to the effect that any redevelopment should ‘reinstate’ the original Georgian façade – although Grafton helped persuade them this should be modified to merely ‘respect’ the street’s 18th-century character.
This stipulation had its origins in a controversy surrounding the construction of an earlier ESB HQ on the site, designed by Stephenson Gibney, which won the commission after a 1961 competition. Historically, Fitzwilliam Street Lower had been laid out as townhouses for the wealthy in the 1760s during the time of the Protestant Ascendency under British rule. Within a hundred years the huge houses, no longer fashionable, had been divided up into smaller dwellings, an architectural transformation described by Steven Connolly, associate director at Grafton, as being ‘from palaces to tenements’. It bore witness to the flexibility of Georgian architecture, if nothing else.
The street and its surroundings remained relatively neglected through most of the 20th century, not least because of the area’s association with the Ascendency, and no formal protection was in place when the row of 16 townhouses was demolished in 1965 to make way for the Stephenson Gibney-designed building. By then the project had played out in the newspapers as a textbook modernist progress versus preservation architectural battle (the street had the longest extant Georgian terrace). It even prompted questions in the Dáil. Interestingly, the street façade of Stephenson Gibney’s design, while uncompromisingly modernist, did nod to the Georgian terrace it replaced, albeit in a slightly clunky way with its long, low proportions, repetitive vertical gridding of windows and reddish concrete panels matched roughly to the surrounding brick terraces.
By the noughties, that building, together with other standalone ESB buildings on the site, was no longer deemed fit for purpose, its architecture in turn out of fashion, and Grafton won the 2009 design competition to replace it. Connolly says retrofit was considered but issues such as 59 internal changes of level decided them against it. Given the swings of the architectural pendulum, this option would likely have been explored further had the competition been held today.
From the street, the success of Grafton’s façade is not so much in how it replicates the overall regularity of the surrounding Georgian architecture as much as in its subtle irregularity and the differing grain between houses. This is gently picked up in the variation of openings – from larger ones where the façade acts as a colonnade-like screen to inner courts and voids, to smaller ones, where office floors sit forward to the street. The whole is set out on a 15m bay width that keeps in rhythm and tenor with the roughly 7.5m repeat of the original houses, like a musical variation on a theme.
Diagram of the woven landscape and plot grain
Sadly, there are nowadays no brick manufacturers left in Ireland. But there is a warmth and softness to the bricks employed, manufactured by Gillrath in Germany and chosen after a painstaking selection process. They are noticeably long and deep, with a distinctive burnt mottling from being kiln-dried. Nicely, the four-storey brick street frontage, from ground level up, is formed of loadbearing solid brick construction, lime-bedded and pointed (avoiding the need for mastic-filled movement joints) and dressed with Leinster granite.
Composed of two thermally-separated layers, the inner skin supports the building’s concrete superstructure, which is cantilevered out to the outer, allowing for independent movement.
The building’s superstructure is primarily flat slab construction, but in places Vierendeel trusses have been used to enable the voiding out of the large volumes and spans in and around the inner courts – including where a two storey-high, 18m-wide block spans 15m across a triple-height sunken courtyard.
So, despite its gentler brick face, this is still a heavily massed concrete-framed building in the manner of previous Grafton schemes, its structural gymnastics just more orthogonal, less expressively celebrated. There is certainly carefully considered reduction of embodied carbon – the concrete used has admixtures of 50-70 per cent GGBS – but it’s not a factor driving the design. This reflects in part the scheme’s long genesis. The basics were set down more than five years ago, before embodied carbon reduction came so much into focus.
But at a fundamental level, too, one knows that Grafton’s heart is firmly in making this sort of big-boned architecture, with sustainability very much understood in creating structures fit for the long term. Certainly, in the metrics of operational sustainability – important no doubt for ESB’s green energy credentials – it scores highly, with its high thermal mass from large areas of exposed concrete as well as sporting a super-insulated envelope and utilising air and ground source heat pumps.
The big structural spans, enabling open floor plates, allows for potential repurposing, too. Indeed, Connolly says the building has been designed with possible residential conversion in mind, comparing this flexibility to that of the Georgian architecture around it. Internally, Grafton has just topped and tailed the spaces for fit-out, with timber window linings and marble-clad lift lobbies.
Spatially and experientially this is deft architecture. There is, in particular, a beautiful calibration of its extended series of threshold spaces and scales leading off the street to the two main office entrances: the one to the south serving ESB, and the other to the further commercial office space (which will be the new Irish HQ of Salesforce).
At the pavement, you cross a generous strip of lightwell to the basement, matched to those of neighbouring houses, lined in light-reflecting cream glazed tiles. Passing under the thick brick street façade, a second inner line of brick piers reads as an inner skin, a cloister-like internal walkway running between. This arrangement is repeated at three levels, creating external corridors between offices. Looking back from the inner entrance courtyards, it all forms a screen to the street, aqueduct-like in scale at 21m tall. The verticality is further underlined by façades formed of concrete panels, with vertical fins acting as brise-soleil, their granite aggregate matched to the Leinster granite dressings. The solid-to-void ratio also reduces with the height, admitting more light below and creating more shade above.
The scale is taken up a notch by a deep sunken garden court, separating the two main entrances, itself containing storey-deep tree planters. The greenery is just getting established but promises an almost park-like scale of planting that is no mere nod to biodiversity. It also brings light not just deep horizontally, but also vertically into the plan.
And it nicely flips the idea of the grand corporate lobby from internal space with token biophilic plant dressing to a lush, grand and shared external space. It is shared, too, by the public, via a reinstituted ginnel-type public pedestrian route running through the block, lining up with secondary streets to the front and back.
To the rear, off James Street East, the (non-structural) brick façade weaves around smaller courts, its variegated block formations looking almost British Library-like – chunkily appropriate for facing off some rather fine Scott Tallon Walker Miesian commercial buildings behind.
This is not Grafton resting on its laurels, but wonderfully accomplished architecture: massively flexible, urban in its ambition, sensitive and deftly handled. However, while the utter solidity is very attractive, one might have expected to see a shift to lower-carbon materials, with more use of stone, or secondary structure switched to timber (more akin to Georgian construction) – especially since Grafton is currently working on an all-timber building, the Anthony Timberlands Center for Design in Arkansas.
So, while this is a brilliant summation of Grafton’s skills as architects, it feels like one where modern Irish architecture has come from, and not perhaps where it is going.
The challenge for Grafton was to find a way to create a modern office building to sit comfortably amid the restrained elegance of the Georgian context at the centre of Dublin’s Georgian Mile and between the 18th-century grandeur of Merrion and Fitzwilliam Squares. To begin this process, we set about analysing the built fabric of the Georgian streetscape, including the rhythm of its windows and doors, hierarchy of floors, gently stepping parapet lines, chimneys and threshold of railings, bridge and basement, which bring light down to the lower level – which together represent the fundamental machinery of Georgian architecture. The proposal works within this vocabulary to make a building sensitive to its surroundings yet representative of its own time.
The new building continues the Georgian streetscape and parapet height of Fitzwilliam Street Lower. This edge is crafted with a loadbearing brick wall designed and detailed to harmonise with the existing brickwork of the street, to feel familiar and new at the same time. It feels familiar because it relates to the repetitive and cohesive existing brick walls, each house slightly different from the next. It feels new because it is similar but not the same, with new elements subtly introduced to accommodate new uses and ways of building. The materials have been chosen to be sympathetic, as well as innovative.
To James Street East, a series of brick gables forms blocks that open and set back to create courtyards, connections and sunken garden spaces, introducing landscaping to the street and framing vistas through the scheme.
The building’s sustainability agenda aimed to deliver a healthy and energy-efficient design for its occupants: a high-quality work environment, delivering flexible and adaptable floor plates, naturally ventilated spaces utilising high-quality robust materials and workmanship that will stand the test of time. Grafton Architects and O’Mahony Pike Architects
Grafton and O’Mahony Pike Architects were appointed following an architectural design contest in 2009. The brief was to redevelop the site primarily as a high-quality HQ for ESB with ancillary commercial, potential retail and residential space for third party use. ESB sought a world-class, sustainable and innovative building, capable of future subdivision while providing a viable commercial return.
The contest also assessed the entrant’s approach to sustainable design, energy conservation, Building Energy Rating, and anticipated energy consumption and CO2 emissions. The completed development has achieved a BREEAM Excellent rating and a BER of A3. Heating and cooling are delivered with ground and air source heat pumps combined with natural ventilation, with zero local carbon emissions, aligning with ESB’s net zero goals.
A key element in the contest was the proposal for the street façade, which was required to demonstrate respect for the surrounding streetscape and protected structures. The quality and sensitivity of Grafton’s design overcame suggestions to retain the existing 1970s façade or reconstruct a semblance of the Georgian façades removed in the 1960s. It thoughtfully restores the eastern edge of Fitzwilliam Street Lower, in harmony with the rhythm and feel of the historic street, while clearly being something new.
In addition, a new pedestrian street through the building, combined with sunken courtyards and a public plaza, generously enhances the surrounding Georgian amenities. The finished development is a testament to Grafton Architects’ design approach and integrity in building and placemaking: a magnificent addition to the built environment in Dublin City. James Maxwell, technical director, ESB Project Fitzwilliam
This project was designed to be sympathetic to its setting but to display proudly its fabric in the form of exposed concrete finishes internally with a mixture of hand-laid brick and precast concrete externally.
The superstructure predominantly consists of reinforced concrete flat slab construction, with a typical slab thickness of 325mm at suspended slabs and a deeper 350mm slab at ground floor and roof levels to account for larger build-ups. The perimeter concrete elements behind the 3m module of precast façade are engaged with the structure and act as loadbearing elements throughout, leading to the adoption of transfer structure at lower levels to achieve the design’s clear spans and building offsets.
Along Fitzwilliam Street Lower, brickwork is used as a primary loadbearing element to complement the development’s setting. To meet requirements of disproportionate collapse without the requirement for vertical ties up through the walls, the below-ground-level sections of the wall were cast in situ.
The project includes a number of novel uses of concrete in the form of Vierendeel trusses. The first of these is used to provide a two storey-high, 18m-wide structural block with a clear span of 15m over a part triple, part four-storey height space beneath.
This block consists of two Vierendeel trusses formed in the outer walls with downstand beams at third points across the width of the block to limit the load onto the Vierendeels. The same engineering principles were adopted in two of the rear courtyards facing onto James Street East, but with the trusses acting as cantilevers of up to 7m in this area. Ian Crehan, associate, O’Connor Sutton Cronin
Fitzwilliam Street Lower façade The wall to Fitzwilliam Street Lower is composed of two solid brick composite walls. The outer leaf is self-supporting brick while the inner is a loadbearing brick wall that supports a concrete superstructure. A thermally insulated cavity separates the two.
The brick used is a large (240 x 115 x 73mm) custom-made brick from Gillrath brickworks in Germany. This wall’s overall width is 800mm and it rises 21m from the lower lightwell. Both leaves are built in Flemish bond with lime bedding and pointing. The use of loadbearing masonry with lime bedding allows for a wall free from mastic-filled movement joints. Where there are movement joints, these are placed every 15m in line with the width of the bays.
The loadbearing structure of brick piers stack from level to level; there are no concrete columns nor steel frames embedded in the structure. The slab has exposed concrete coffers bearing onto the brick structure and varies in depth from 150mm to 250mm. All elements that require structural support – staggered steel frame windows, granite surrounds, copings and gates – are all fixed to the inner brickwork and are cantilevered over the external wall, allowing for independent movement between the inner and outer parts. The windows are finished internally with a solid oak liner, which splays to allow additional light from the west.
The windows to the street are a thermally broken steel window system with a ventilation flap incorporated at the step in the section. The window openings in the outer brick wall are lined with a feathered reveal of lime mortar. Masonry flat arches are used to form the window openings. Larger openings make use of built-in loadbearing precast concrete lintels.
Leinster granite is used extensively on the street façade for sills, steps, kerbs, parapets, railing base and colonnade linings. The street side wall of the lower lightwell is lined in glazed bricks to reflect daylight into the lower ground level and courtyards.
Courtyard façades The courtyard façades are constructed from precast concrete panels and canopies with two grit blast finishes, one rougher than the other. The panels are composed of white cement concrete with a granite aggregate.
In terms of support, the panels at lower levels are stacked whereas on the upper floors they are corbelled off the concrete superstructure. The plan geometry of the panels varies depending on the orientation of the façade. Deeper fins on the south-facing façades assist with solar control.
The openness of the panels varies from the roof to lower ground floor, with the solid-to-glass ratio reducing as the building descends, allowing for additional light penetration to lower levels.
A high-performance aluminium window system is used throughout the non-Fitzwilliam Street Lower façades. The system has custom profile fins to the front and rear perimeters that act as closers to the cavity on both sides. Each 3m bay is composed of a large, fixed window, a solid side-hung vent and an upper BMS-actuated top-hung vent.
Superstructure The superstructure is an exposed concrete frame with suspended flat slab floors. The use of GGBS was maximised in the project: 70 per cent GGBS was used in the lower floors and 50 per cent GGBS in the upper floors. A series of concrete Vierendeel trusses allow for larger overhangs and clear spaces. The column structure changes orientation as the structure descends, allowing for the increase in window dimension and light to the lower levels.
At level 4 structural transfer beams accommodate changing block widths from an 18m floor depth to 15m above. Precast concrete soffits are cast as permanent formwork with cast-in lighting. Chilled slabs are incorporated into all roofs. These are inhabited with various soil depths, biodiverse roof finishes, bees and solar panels. Grafton Architects and O’Mahony Pike Architects
Start on site June 2017 Completion January 2022 Gross internal floor area 45,000m² Construction cost Undisclosed Architect Grafton Architects and O’Mahony Pike Client Electrical Supply Board Ireland (ESB) Structural engineer O’Connor Sutton Cronin M&E consultant BPD and Axiseng Quantity surveyor Linesight Project manager Lafferty Principal designer Grafton Architects Approved building inspector i3PT Main contractor PJ Hegarty & Sons CAD software used Revit Façade consultant Buro Happold Acoustic consultant AWN Consulting Sustainability consultant BDP and Axiseng Fire consultant Michael Slattery Associates Landscape architect Bernard Seymour Landscape Architects Thermal modelling Passivate
Percentage of floor area with daylight factor >2% 40% Percentage of floor area with daylight factor >5% 20% On-site installed energy generation 20% Heating and hot water load 8 kWh/m²/yr Total energy load 67.7 kWh/m²/yr Carbon emissions (all) 13.3 kgCO2/m²/yr Airtightness at 50Pa 2.52 m³/hr/m² (Block B as built) Overall thermal bridging heat transfer coefficient (Y-value) Not supplied Overall area-weighted U-value 0.25 W/m²K Embodied/whole-life carbon Not supplied for frame and superstructure Predicted design life 60 years
Tags Brick Dublin ESB Headquarters Grafton Architects O'Mahony Pike
Sign in or Register a new account to join the discussion.
We use cookies to personalize and improve your experience on our site. Visit our Privacy Policy and Cookie Policy to learn more. You can opt out of some cookies by adjusting your browser settings. More information on how to do this can be found in the cookie policy. By using our site, you agree to our use of cookies.