Coade stone at Croome

Coade stone is a highly mouldable and versatile artificial stone, with unique properties that makes it far superior to real stone in resisting the effects of erosion and weathering.

It was first introduced to Croome by 'Capability' Brown in 1778, when the ‘Tablets of a Grecian Wedding’ were inserted in the Island Temple, after which the 6th Earl of Coventry seems to have become a real convert. The Sphynxes were next to be installed followed, in around 1800, by all the other pieces – in association with James Wyatt.

Coade stone was invented by Eleanor Coade, born in Exeter on 3 June 1733, at her stone making factory at Kings Arms Stairs, Narrow Wall, Lambeth around 1770, a site now occupied by the Royal Festival Hall. In 1771 she appointed John Bacon as workshop supervisor, and it was his neo-classical designs, together with Eleanor’s talents as a sculptress, which helped create demand for monuments and ornamental features made from this new material.

Eleanor herself named the material ‘Lithodipyra’, taken from the ancient Greek for ‘twice fired stone’, but it was others who later named it after her. Coade stone was produced from 1771 until around 1831, 10 years after Eleanor’s death. The ultimate demise of Coade stone was brought about by the invention of Portland Cement. Research suggests that there are around 650 pieces of Coade stone surviving today.

Notable examples of Coade stone, other than those on the Croome Estate, include the South Bank Lion on Westminster Bridge; Captain Bligh’s Tomb; and Nelson’s Memorial at Burnham Thorpe. Coade stone was also used on such notable buildings as Buckingham Palace; Castle Howard; the Royal Pavilion at Brighton; the Imperial War Museum and even Rio de Janeiro Zoo.

Eleanor Coade died in Camberwell Grove, Camberwell, London on 16 November 1821, and she was buried in an unmarked grave at Bunhill Fields Cemetery in Islington.
 
Coade stone process and formula

The production process for Coade stone comprised a number of stages. First of all a model of the proposed piece was made, from which a plaster cast/mould was taken. The Coade clay was then inserted into the mould and fired, before being baked in a kiln at 1,100 degrees Fahrenheit for 4 days The, then secret, formula for Coade clay comprised a mixture of 10% grog (a finely crushed waste from the kiln); 5-10% crushed flint; 5-10% fine quartz or sand; 10% crushed glass; and 60% ball clay (from Dorset or Devon).

Read more about Coade stone in the National Trust