Modest building fit for a king
The visitor centre at Sutton Hoo in Suffolk, a seventh-century burial site for the kings of East Anglia, is a simple, unobtrusive design, which takes its aesthetic from its surroundings and its Anglo-Saxon ship exhibit
In 1939 archaeologists unearthed the burial ground of the seventh-century kings of East Anglia on the estate of Sutton Hoo, near Woodbridge, Suffolk. Huge timber ships laden with precious objects and artefacts were buried with the kings. It was a momentous discovery and changed the perception of how people lived in the Dark Ages.
The treasures were donated to the British Museum. The Sutton Hoo estate - a substantial house built in 1910 in grounds of 99ha, which included the gravefield site - was donated to the National Trust in 1998, which commissioned architect van Heyningen and Haward to design a new visitor centre.
The practice has taken a modest, low-key approach to the design of visitor facilities.
Reception and exhibition spaces are split into two barn-like timber buildings, set among trees at one corner of the site, close to the main car park. Their gable-end entrances, each with an overhanging roof to give shelter in bad weather, face each other to create an informal courtyard. Both are designed as modest and non-intrusive elements to be, as the architect explains, 'non-assertive and appear recessive in the landscape'.
The two buildings are framed with Douglas fir and clad on the outside with horizontal Douglas fir ship-lap boarding. It is a timber aesthetic partly related to the Suffolk vernacular of black weather-boarded barns (although the centre's buildings are stained dark grey, as it was thought black would be too strong), and partly reflecting the timber construction of the Anglo-Saxon ships. The use of timber also accords with the ethos of the client, the National Trust, to commission buildings that are sympathetic to their surroundings and to use materials from local and sustainable resources. The Douglas fir used for frame and cladding was sourced in the Lake District and treated with environmentally non-polluting preservative based on boron. The roofs are covered in metallic grey zinc sheet, which matches the grey boarding of the walls.
The exterior may be unassuming but the interior of the reception building is a delight, with light flooding in through the glazed walls and lantern - its effect enhanced by translucent white-stained timber boarding on the walls and ceiling. The building contains the information and ticketing desk, a shop, WCs, a generous lobby space for visitors to gather and orient themselves and a kitchen and restaurant with an outside terrace, which gives dramatic views over the site and down the valley to Woodbridge.
The interior of the exhibition building is more dramatic. In its spacious hall, which rises to the apex of the roof, is a reconstruction of a ship burial. The mid-section of the ship is set in the basement with a viewing platform at ground-floor level. Opening off the hall are an audio-visual theatre and a 'treasury room' where some of the original finds are on display.
Both buildings are constructed on similar principles. The whole structure is formed of Douglas fir sawn structural timber chosen from a small range of standard sizes - 150mm x 50, 75 or 150mm. The 150mm square section was used where it was visible and paired 150 x 75mm sections bolted together were used where concealed (a cheaper option).
Paired 150 x 75mm sections were also used, bolted either side of a steel flitch plate where additional strength was needed (for example, this detail formed the connection between the external trusses that support the overhanging roof on the gables of the reception building).
Similar paired elements were also used as diagonal struts in the walls to give lateral stability.
Connections between timber elements are usually bolted and often need many bolts to transfer loads, which can look unsightly.
To avoid this, Paul Batty, structural engineer at Price & Myers, designed specially fabricated connection plates for the internal trusses.
In principle, the connection is neither a flitch nor a simple propped rafter, but is designed to provide end bearing for the timber with the minimum use of bolts.
The walls are formed of 150 x 150mm wall posts with insulated studwork infill between.
They are clad on the outside with Douglas fir ship-lap boards, screwed in 2.2m long panels with 25mm vertical shadow gaps between to accommodate movement. The posts are clad with vertical timber cover pieces. On the inside, the walls are clad with horizontal tongued and grooved Douglas fir boards.
The pitched roof structures are supported by steel and timber trusses (see pages 6-7) overlaid with 150 x 75mm purlins, insulation and a zinc roof covering. The spaces are lined with relatively hard surfaces, so to provide sound absorption the ceilings are clad with Douglas fir slats spaced 25mm apart and backed with acoustic insulation and finished with an intumescent coating.
Sutton Hoo is a modest and apparently simple building, yet it has a subtlety of detail, which is the result of careful analysis by both architect and structural engineer. The end product is a delight - and a real contribution to sustainability.
ARCHITECT van Heyningen and Haward Architects Birkin Haward, Chris Wilderspin, John Bell
STRUCTURAL ENGINEER Price & Myers Sam Price, Paul Batty
SERVICES ENGINEER Max Fordham & Partners
QUANTITY SURVEYOR Davis Langdon & Everest
TIMBER SUBCONTRACTOR SP Cousins, Joiners