Roman cement

Hadlow Tower is of brick-built construction and was finished with ‘Roman cement’ render to give the impression of stone. The bricks would almost certainly have been locally made and Roman Cement was originally produced in Kent.

James Parker, a clergyman and cement manufacturer developed ‘Roman Cement’ in the 1780s at his plant on Northfleet Creek, Kent in response to the need to produce a cement which had a fast drying time. His patent for the material in 1796 described the product as ‘A certain Cement or Terras to be used in Aquatic and other Buildings and Stucco Work’.  The name was possibly adopted because it was similar to the quick-drying cements produced in the Roman period with which they built their harbour walls. Parker used naturally occurring clay-rich limestone found as nodules in the London clay deposits on the Isle of Sheppey (samples of which can still be found on the beach). The nodules were burnt and then ground to a fine powder which, when made into mortar with sand and water, set in 5 to 15 minutes. For the grinding process Parker may have used an ancient tidal water mill at the head of the creek or a nearby windmill. Parker sold the patent to architect Samuel Wyatt who, with his cousin Charles, produced cement under the name of Parker & Wyatt. Interestingly Charles was cousin and brother-in-law of James Wyatt (brother of Samuel) who designed the fateful Fonthill Abbey, upon which Hadlow Tower was modelled.

When Parker’s patent expired several other manufacturers produced this cement using similar deposits of limestone which contained integral clay but eventually artificial versions became more popular as their consistency could be more easily regulated.

Roman Cement is no longer made in England and has to be imported from Grenoble in France. Vicat ‘Prompt’, which was used to recreate the render and ornamentation of Hadlow Tower, has been made from the same limestone in the French Alps for the last 150 years. The Vicat company was established by Joseph Vicat in 1858 after his father Louis, engineer to Napoleon, had experimented with quick drying formulas from naturally occurring constituents. Their literature tells us that Vicat Prompt is an ideal choice of binder when very fast setting/hardening is required and where, adhesion, long term strength, resistance to corrosive water or sea water, and waterproofing is needed’.

Paye, a company specialising in restoring historic facades, undertook the work of re-rendering and replacing the extensive exterior ornamentation. Some of the decoration had already fallen away due to the original iron fixings rusting and expanding but the majority was removed in the 1980s for safety reasons. Any original decoration which had been retained was removed and re-pinned with stainless steel fixings. Much of the new decorative work was made in moulds off site and then cemented in position; however, some of the straighter runs were made in situ using a device called a ‘horse’, in which a metal former inserted in a simple wooden framework shapes the damp mortar as it is guided along wooden battens (see photos below).

Saturday morning 6th September 1823 At a village called Hadlow, there is a house belonging to a Mr. May, the most singular looking thing I ever saw. An immense house stuck all over with a parcel of chimneys, or things like chimneys; little brick columns, with a sort of caps on them, looking like carnation sticks, with caps at the top to catch the earwigs. The building is all of brick, and has the oddest appearance of anything I ever saw.’ From William Cobbett’s journal ‘Rural Rides’, published in 1830.

Picture of Northfleet Lime Kilns by kind permission of the National Library of Australia