The Dome Sports Centre, Mildenhall, Suffolk

Summary

A concrete dome built on 29 April 1977 using the Bini construction system.

Description

MATERIALS: Concrete, with steel reinforcement. The attached reception building is steel and concrete block with corrugated-steel roof.

PLAN: The main space is circular, with an additional arc-shaped section following the curve of approximately 90 degrees of the eastern side of the circle, and a rectangular area intersecting it to the north, for the reception building.

EXTERIOR: A white concrete dome, 11 metres high, with a diameter of 36 metres. On the outer surface the waterproof liquid-applied elastomeric membrane is visible. The central opening from which the vibrator cables would have been fed during the process of setting the concrete, is covered by a three-metre ventilation cowl.

There is a drainage channel and grill in the ground around the circumference of the dome adjacent to the original ring-beam. The building has sets of double doors at four equidistant points around the exterior. There are two air ducts mounted on the northern side of the roof.

Attached to the east side is a curved section, part of the original design, flat roofed squash courts, and a concrete and glass section in the shape of two unequal triangles leaning abutting each other.

INTERIOR: There is a main gymnasium space using the full height of the dome, and most of the space. To the north and south edge are two-storey blocks of concrete block construction, providing smaller rooms. The upper floor to each block is accessed by a stair at the western end. The curved outer sector gives access to a pair of squash courts, and at its north end opens into the reception extension.

History

In 1963 the Italian architect Dante Bini (born in 1932) invented his building system, using the power of air, by which he could cover a giant balloon with concrete and inflate it, to construct a dome in a single day. He constructed his prototype dome in 1965 in Castelfranco, near Bologna, and named his construction a “Binishell”.

The innovative Bini method was as follows: firstly a concrete sill beam which marks the outer circumference of the dome is partially sunk into the ground. Then a neoprene membrane, folded like a parachute, is placed within the ring beam’s circumference. On top of the membrane a grid of expandable steel rods is laid. Concrete, mixed with varying amounts of plasticizer and retardant, to ensure its continued malleability, is then poured on top and a further, outer membrane is stretched across the top of the wet concrete. Next, the lower membrane is inflated through ducts under the ring beam to raise the dome, a process which can take as little as one hour. To smooth the concrete, a series of four “vibrators” on small carts are suspended from the top of the dome with cables: each one manually operated by an abseiler. The membrane is kept inflated for another 60 hours while the concrete sets, after which it is deflated, and any required window and door openings are cut through the concrete.

With the success of his experimental constructions, Bini was invited to the USA, and later Australia and Liberia, to build with his system. It is reported that over 1,500 “Binishells” or “Binidomes” were constructed worldwide between 1970 and 1990. ‘
In Britain the rights to the Binidome construction method were purchased by NorWest Holst Construction, who named it “parashell” for the British market. Building Design in December 1974 reported optimistically on the new construction method, reporting that two domes were being erected by NorWest Holst near Leeds, and a new sports centre was being erected in a “north of England town”. About 20 clients in Britain were reported to be interested in the construction technique. Eventually, however, only three domes in England are known to have been constructed. The first was put up at the NorWest Holst Depot at Tingley in Yorkshire, in February 1975. It was dismantled at an unknown date.

In February 1977, the architect Michael Godwin, who had admired Binidomes on a visit to Italy, supervised the building of a Parashell sports centre for Malvern Girls School. His vision was to make a very light space, and he set the dome within a landscaped pool, and cut windows all around the base of the dome, to allow light to bounce in off the water. This dome was listed at Grade II in 2006.

In April 1977, the Dome Sports Centre at Mildenhall Upper School was built, as reported in “Building Design” on 6 May 1977, which claimed it was the first time the Parashell system had been used commercially in Britain. The architect was reported as J Brian Jackson, Suffolk’s County Architect, and the project architect was Simon Conolly. Conolly had received a grant to research air structures in the 1960s as a student at the Architectural Association. He proposed a parashell construction for this job, which enabled the building of a multi-purpose hall of over 1000 square metres for a budget originally intended to provide 600 square metres.
The Dome was constructed in a single day on 29 April. Once the concrete was set, the exterior was sprayed with insulation and finished with a waterproof liquid-applied elastomeric membrane As part of the original design the curved structure to the east was afterwards added, constructed by conventional means. Rooms were also added internally, although the majority of the space was left open as a gymnasium. The interior was also covered with an impact-resisting, lightweight, sprayed, perlite finish to reduce the reverberation time of the bare concrete from over half a minute, to under 2 seconds. (It is reported that it was impossible to hold a conversation before the finish was applied.)

In 1984 a prominent angular extension was added to the front (to the north), joined to the curved eastern structure, in order to provide a larger reception area.

The Dome closed to the public on 24 June 2021, when a new sports centre opened elsewhere in Mildenhall.

Reasons for Listing

The Dome former Sports Centre in Mildenhall, built on 29 April 1977, is listed at Grade II for the following principal reasons:

Architectural interest:

* for its innovative and economical construction system, invented by the Italian architect Dante Bini;
* known in the UK as “parashell” construction, the concrete structure was erected in a single day by inflating a giant membrane covered in wet concrete, which then set in the shape of a dome.

Historic Interest:
* it is an extremely rare structure; only three domes were constructed nationally using the parashell system, and this is one of only two that survive.

External Links

Historic England Listing

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