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Thursday 10 July 2008

Leweston Water Tower

Image Mr RJ Whittick FRPS from Images of England.
Date Photographed: October 1999

Leweston Water Tower, Dorset

Much has been written of the symbolism of buildings in general and thus in popular memory of the 'twin towers' of the original Wembley Stadium.

Today "twin towers" has a whole host of meanings despite being dominated by the World Trade Center. Petronas, JRR Tolkien and Wembley are some others but it can be argued that their significance is all one.

Somewhere deep in our subconscious, from the time our forefathers erected standing stones, towers in pairs have stood for portals or boundaries for the passage of things; the light of the sun, prayers or sacrifical offerings, onto somewhere else. It can be argued that a single standing stone has one (often phallocentric) meaning whereas two is completely different, although not unrelated. Two towers together seems to make an impact greater than the sum of their parts.

Those that consider such semiotics may be interested to know that the original Wembley stadium's architect evidently had a thing for towers and there are at least two other similar examples still standing. For expediency, two sources have been cut and pasted below:

National Monument Record:

Concrete structure with conical copper roof. Octagonal on plan with angle pilasters. Vertical profile slightly convex. Doorway at ground level with polygonal arch. 3 tiers of narrow slit windows diminishing in height towards top of the tower. Top stage an open viewing platform. External timber winding stair. Interesting example of Art Deco design.

Concrete, Oct 2002 issue:

When Sir Eric Rose purchased Leweston Manor, near Sherbourne, in the late 1920s he decided to improve the water supply on the estate by constructing a water tower. He chose Maxwell Ayrton as his architect who, with Sir John Simpson, had been the architect for Wembley Stadium and the British Empire Exhibition of 1924. Sir Owen Williams was the structural engineer and Sir Robert McAlpine the contractor for this large project. A similar water tower to Leweston at Wappingthorn Farm, Steyning, Sussex was profiled in The Architects' Journal for 14 January 1931. Ayrton and Williams collaborated on this structure so, although Owen Williams' office now has no record of either structure, it seems reasonable to assume that the same team designed Leweston water tower.

The tower was built in Ferroconcrete, which was popular at the time, and is 16.Sm tall, with an additional Sm of timber for the belvedere. The inside face is a 5.7m-diameter circle; the outside is octagonal with walls i50mm thick at their narrowest. Unusually, the concrete is a 6mm aggregate mix with an exposed gravel aggregate finish. The walls are, by modern standards, extremely lightly reinforced with a single central layer of mild steel. Consequently, there was little spalling, which has been repaired with a site-- batched repair concrete.

Another unusual aspect is that the tower had two water tanks, one located approximately around the middle third of its height and the other at the top third. These had 300mm-thick heavily reinforced bases and a central octagonal shaft for access. Inner tank surfaces were waterproofed with 25mm of mastic asphalt. Around the exterior of the tower is an oak staircase, cantilevered from the walls. This was originally secured with bronze tie-roads, and leads to the top-level belvedere, which gives a panoramic view.

Around 1980, Leweston was put on the mains water supply and the tower became redundant. Over the next 20 years, the tower was allowed to decay, but the concrete structure and roof remained fundamentally sound. It was Grade II listed in October 1986, and two years later sold and converted for holiday accommodation.

In 1999, the property was bought by Patrick Firebrace, contracts manager for Concrete Repairs Ltd for the past 23 years. He appointed Roger Mears Architects to improve the earlier plans so they conformed to the Building Regulations. At the same time, he asked his structural engineer brother to justify his belief that the material used in the conversion should be concrete. The floor of the upper tank had to be completely removed as it did not coincide with sensible new floor levels, but the lower one could remain. Two new floors were to be built below it and two above.

At each new floor level, reinforcement dowels were set into the walls with polyester resin. Reinforcement was cut and bent on site and the concrete was a site-hatched Lytag mix of average cube strength 57MPa. This lightweight concrete was used primarily because of its better insulating properties since the new floors and wall would butt up to the concrete tower. It would also impose less dead weight on the supporting dowels and be lighter to pull up the tower.

Before concrete work began, the upper tank was removed by high-pressure water cutting. When the reinforcement was exposed, it became apparent that it had been bent on site as each bar spanned full width with bobbed ends into the wall. It could therefore be left in place, stiffening the top section of the tower until the new floor below was constructed.

After completion of the concrete work and fixing of new metal windows, the inner face of the tower was sprayed with SOmm polyurethane foam. The central shaft of the stairwell was filled with a glass block wall in a frame constructed from precast concrete columns and in-situ concrete beams. Around the bottom perimeter of the tower, an artificial Purbeck stone path was constructed in pattern-- imprinted concrete by Architectural Paving Systems.

There were two years between completion of the tower purchase to the finish of the conversion. During this period, an unwanted civil engineering concrete ruin designed by a leading 20th century architect and engineer has been restored and converted into a comfortable and interesting house.

Source: Concrete, Oct 2002 issue

2 comments:

Michael said...

I in Massachusetts, U.S.A, and we've been trying to sort out a water tower question. (see: http://greatergrafton.wordpress.com/2008/11/20/well-that-was-unexpected/).

Some think its a Civil War lookout tower (I'm skeptical), and others think its a water tower.

Do you know of any specific signs on the tower structure that could confirm one way or the other?

Nat Bocking said...

After Googling the tower I would say you will have to look to see if there is any evidence of a pump building nearby and also if there are any buttresses or pockets for beams to support what would have been a wooden tank. Such towers with internal wooden tanks are not unknown but given the cost of stone, the tank would be likely be exposed. IMHO it's not a strong cadidate for a water tower but I look forward to other contributions.