The restoration of Wellington Arch in Hyde Park Corner was discussed during this year\'s Donovan Purcell Memorial Lecture from two perspectives - that of the client (English Heritage) and the stone specialists (Stonewest).
The lecture was held in the Flett Theatre of the Natural History Museum. The first perspective was presented by Alasdair Glass of English Heritage. The second came from Nick Wilson, a director of Stonewest.
The lecture is organised annually by Stone Federation Great Britain on behalf of the Standing Joint Committee on Natural Stones. The event is sponsored by the architectural practice of Purcell Miller Tritton and regularly attracts 200 or more influential designers, conservators, clients and contractors, as it did again this year.
Alasdair Glass was introduced by John Bysouth, a stone consultant who is chairman of the Standing Joint Committee on Natural Stones. Glass said: It was people like John Bysouth who made me aware you could only get to grips with stone buildings if you got to grips with stone people . . . There\'s no point giving someone a specification and telling them to get on with it; you have to explain to them why they are doing it.
Glass ran through the history of Wellington Arch and explained how it had carried different statues. He said the quadrega currently on top of it, as it had been since 1912, was as important as the arch itself and remained the largest bronze sculpture in the country - it weighs 38 tonnes.
He said when English Heritage took responsibility for the arch in 1999 it had been neglected for half a century. He spoke about the restoration of the arch, designed by Decimus Burton in 1825 and moved to its current position in 1883 because it was blocking the traffic at Hyde Park Corner.
The arch was once home to a police station, but now the rooms inside are being used for an exhibition explaining the history of the arch and sculptures in London. A public viewing platform has also been created round the top of the arch below the quadrega.
Glass said the work of the restorers of Stonewest is now put under the unforgiving glare of low angle spotlights every night. The lights would show up any imperfections but there were none.
Nick Wilson said Wellington Arch gave Stonewest the hat-trick as they had previously worked on the restoration of Admiralty Arch and Marble Arch.
He spoke about the cleaning of Wellington Arch, so thick with pigeon droppings that removing it was like breaking away wattle and daub. Cleaning the stone included using poultices on copper and iron sulphate stains and the Jos and Doff systems.
Wilson spoke about the carving work carried out on site, including a new capital cut from a 1.25 tonne piece of Portland limestone that took carver Dave Baker eight weeks to fashion. There were also 22 new lion head masks required as well as many other embellishments.
Repointing was required and the specification originally called for the use of hacksaw blades and no angle grinders. Complete nonsense, in my opinion, said Wilson. Angle grinders were used after Stonewest operatives were able to demonstarte to English Heritage that there would be no damage to the stonework, even though the joints were just 3mm and the mortar had to be removed to a depth of 25mm.
It had originally been intended to remove the whole of the east and west entablatures, but Stonewest demonstrated that this would not be necessary in order to carry out repairs required.
A novel solution was found to the structural repair of a column by cutting out stone and fitting inserts. (For more details of the restoration of Wellington Arch see NSS December 2000).
The main presentations were augmented by Peter Harrison, President of Stone Federation Great Britain, talking about European standards being introduced for the identification, testing and use of stone - 21 test methods are expected to be published in the next two years - and Graham Lott of the British Geological Survey talking about the Survey\'s new map showing the sites of 2,000 active and historical quarries.