Here’s to You, Sloane Robinson
Client: Keble College, University of Oxford
Architect: Rick Mather Architects
QS: Stockings & Clarke
Main contractor: Benfield & Loxley
Structural engineer: Dewhurst MacFarlane & Partners
Environmental engineers: Atelier 10
Brickwork contractor: Benfield & Loxley
Acoustic consultant: Sandy Brown Associates
Rick Mather’s latest addition to 750 years of architecture at Oxford
University had to hold its own against one of the most famous brick buildings in Britain
For Rick Mather Architects, the choice of brick as the cladding material for the award-winning Sloane Robinson building was a foregone conclusion. For one thing, it shares a quadrangle at Keble College Oxford with two other distinctive brick structures.
The first is Mather’s Arco building, completed in 1995; the second is architect William Butterfield’s 1883 Victorian masterpiece – the first brick-built college at Oxford. The two architects exploited brick in different ways.
Butterfield was one of the earliest and keenest exponents of polychromatic brickwork. But where he used different coloured bricks to create pattern, banding and diapering of the surface to bring together its various masses, Mather has relied on a single, distinctive brick type and colour to achieve the same unifying effect. No complex patterning, just slim, highly textured, stack-bonded Roman-style bricks that draw together the complicated geometry of the architecture.
The £6m Sloane Robinson building sits on a steeply sloping site in Keble’s Newman Quad. The building is parallel to Blackhall Road, which forms one side of the quadrangle. The Arco and Butterfield buildings form the other two sides.
Viewed from the garden, the new building has the air of a Roman temple, thanks to its monumental character and its arcade of double-storey, fair-faced concrete columns. Yet this near symmetrical and somewhat stern facade is counterbalanced by the irregularity of the building’s ends which rise to pinnacles as they change direction, their angle determined by the adjacent Arco building.
The building’s 250-seat, flexible, multipurpose auditorium can be entered from the garden terrace. It has a dining hall and recital room at the higher street level, and above are six seminar rooms expressed on the garden elevation by sharp, prismatic oriel windows, like jewels encrusted in brickwork. These have been designed to maximise views of the Butterfield and Arco buildings. The top two floors house 20 study bedrooms with simple rectangular openings located under two asymmetrical, zinc-covered barrel vault roofs.
At the heart of the building is a hybrid frame, part concrete and part steel. Insitu concrete was used for the lower floors in order to satisfy aesthetic, thermal and acoustic criteria. For the two upper floors, steel was used to facilitate the construction of the zinc-covered barrel vaults.
External walls comprise partially filled brick-and-block cavity construction where the brickwork is laid predominantly in stack-bonded soldier courses. This attractive and contemporary way of laying bricks is enhanced by the slimness of the brick used – 240x40x102mm. This has the additional advantage of allowing the building’s curved ends to be formed without the faceting that a wider brick would have entailed.
The bricks are hand-moulded, thereby imparting a wonderfully rich texture to the building. The street elevation has a less stately, more directional feel. This is partly achieved by the arrangement of the windows, but also by the use of brick panels laid in stretcher bond – an appeal increased significantly by the long, thin bricks. The facade is enlivened by horizontal bands of linear fenestration at upper-ground and third-floor levels. To complete the picture, a vertical glass slit cuts dramatically through the top and sides of the staircase end, leaving a seemingly precarious four-storey brickwork panel on the end of the building.
The necessary stiffening was provided by a slender concrete frame concealed within the blockwork of the inner skin. At every storey, a steel angle bolted back to the concrete structure supports the brickwork and allows the insertion of a horizontal movement joint. Intermediate brickwork between steel angles is secured to the inner block leaf using steel wall ties at 450mm centres horizontally and vertically. Vertical movement joints, which in this case are positioned every 12 m, have been discreetly “lost” in the stack bonded brickwork, with no cutting of bricks necessary. Steel reinforcement is a crucial part of stack bonding, as there is no real bond between the bricks themselves.
Where window openings are large enough to compromise the integrity of the masonry working as a panel, structural engineer Dewhurst MacFarlane specified steel flats to tie the blockwork inner leaf to the floor slabs. This whole philosophy kept the use of bed joint reinforcement to a minimum. The architects resorted to “special” bricks wherever needed, such as where soldier bricks were required to “turn” corners. Although such a detail is easily achieved, it can leave an isolated and vulnerable single brick on the corner. To avoid this, large 140 × 140 × 240mm corner “blocks” were made, incorporating false joints; these 10 mm recesses were subsequently pointed-up to give the impression of a mortar joint. Other specials used included pistol bricks for use on angles and lintels, and special plinth bricks extending around the building at sill levels to impart attractive shadow lines and articulate the brickwork.
Choosing the right brick colour was important for planning consent. The colour used had to harmonise with Butterfield’s range of sandy-to-purple colours in the building opposite. However, achieving a sympathetic shade required the blending of three different types of brick at the works. Furthermore, the bricklayers were advised by the brick maker to vary the work on site by taking bricks from three different packs. Although none of this proved particularly difficult, it entailed making the specials in three different brick colours and interspersing them into the work. The resulting uniformity of colour seen throughout the brickwork is testament to the success of this method.
Low-emissivity double-glazed units are used throughout the building, whether for windows or for the double-storey glazing to the garden elevation. The main entrance, located adjacent to the auditorium on the garden side, has an imposing toughened glass canopy that slopes toward the building. Clamping of the glass support fins to the concrete frame is concealed behind an aluminium-faced backing plate set into the brickwork. This also conceals a gutter that runs into a internal rain water pipe.
The building is also noteworthy from a sustainability point of view. It is the first building in the UK with a geothermal system, which uses a heat exchanger in the basement to connect plastic pipes buried in the piles with similar pipes cast into the concrete slabs. These pipes, which are filled with antifreeze, transfer ground heat from the 20 m deep piles to the concrete slabs. In summer, the system is reversed, and the piles act as heat sinks. This means that the building’s concrete soffits – apart from those in students’ bedrooms – act as radiators in winter, and become chilled ceilings in summer. And there is another advantage: the electricity requirement of the system is about one third less than that used by conventional air-based systems.
Since its completion in October 2002, the Sloane Robinson building has formed a stylish addition to the Oxford skyline. Taking the top category in the 2003 Brick Awards was a major achievement, but there is more to come. Commenting recently on the building, Keble College bursar Roger Boden said that Rick Mather Architects had given the college “amazing spaces – huge shafts of light, glorious views, intriguing corridors, boldness and restraint”. He also paid tribute to the invention and generosity of spirit that pervaded the entire building. Such laudatory remarks are always welcome, but when coming from a client, they are music to an architect’s ears.
For as everybody knows, there’s nothing like a satisfied customer.