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Helmingham Hall Bridges
Helmingham, Suffolk, UK
Helmingham Hall Bridges
associated engineer
John Nash
date  circa 1810
UK era  Georgian  |  category  Bridge  |  reference  TM185577
ICE reference number  HEW 341
photo  © Chris Holifield and licensed for reuse under this Creative Commons Licence
The two ornate white-painted cast iron bridges at Helmingham Hall in Suffolk are among the oldest of their kind still in use in East Anglia. They cross a wide moat to serve private entrances on the south east and north east elevations of the hall, and are still in use.
Helmingham Hall, completed in 1510, is a moated house some 13km north of Ipswich, and is the seat of the Lords Tollemache. Grade I listed in 1984, it is still owned by the original family. Only the estate’s gardens are open to the public.
During the Regency period, the celebrated architect John Nash (1752-1835) was retained to design major alterations to the building. In 1800, he exhibited his Tudor-Gothic proposals at the Royal Academy. Among the drawings on show was one of a delicate cast iron bridge of three equal spans, designed to replace the existing brick arch bridge over the brick-lined moat. However, the two bridges eventually cast by Ransome ironfounders of Ipswich are more substantial in appearance.
The building works were carried out between 1800 and 1803, and it is likely that the bridges were erected during that time or soon after, perhaps from 1805 onwards. It is thought they were completed around 1810. It is also possible that there was once a third bridge, located on the west side of the hall, leading to the moated garden, possibly removed during alteration works in 1840.
The moat is up to 18m wide by 1.8m deep. Each bridge crosses it with three spans — a central 9.6m cast iron span supported on red brick piers, a shorter outer cast iron span of 2.7m, and a timber drawbridge linking the central span to the hall. One of the bridges is wider than the other — the south east bridge is 3.75m between parapets and the north east 2.5m.
The central spans are flattened semi-elliptical arches with level decks. They are each composed of three longitudinal rib arches, 330mm high at mid span and 1.8m at the piers. The arch springings are just above water level, so the maximum clearance is 1.8m. The open spandrels feature vertical members and Gothic detailing, with the 914mm high cast iron balustrading above echoing the spandrel style. Brick jack arches in the piers, and cast iron cross ribs at 914mm centres, link the rib arches.
The outer spans are pointed arches, with decks that slope at 1 in 20.
The brick piers are set on concrete bases, decorated at deck level by stepped octagonal brick pilasters with coned tops on the outer sides of the piers. A terminal pier with similar pilasters stands at the east end of the northern bridge, while the east end of the southern bridge is flanked by two brick obelisks with tall pointed spires, erected in about 1760. The brick-paved carriageways reduce in width at the piers — to 3.1m on the south east bridge and around 1.8m on the north east one.
The drawbridges span about 2.75m and are without handrails. The south east drawbridge is of oak, with timbers 2.9m wide and 203mm thick. The north east one is similar but a little narrower. They are raised every night and lowered every morning, just as they have been since 1510.
The raising mechanism consists of side chains attached to the outer ends of the drawbridges. The chains pass over pulleys set in the walls of the building, then through the walls to larger pulleys and down to counterweight beams. Each mechanism has a chain connected from one of the beams to a windlass, orignially hand cranked by now run by electric motor.
In September 1987, both bridges were designated Grade II listed structures. The hall's oak doors that the bridges lead to are original and are believed to be made from timber more than 900 years old. In 1990, the bridges were refurbished. The brick roadway of the wider southern bridge was covered with a tar and gravel surface, probably at the same time.
There is another bridge by Nash on the estate, constructed at the same time as the moat bridges. It crosses a stream on the east side of the two large fish ponds. This one is red brick, with a tall semicircular arch and a deck some 4m wide between 1m high plain brick parapets. The square pilasters with coned tops at its abutments are of similar design to the octagonal ones on the moat bridges. This bridge was also Grade II listed in September 1987.
Ironwork: Ransome & Co of Ipswich
Research: ECPK
reference sources   CEH E&C

Helmingham Hall Bridges