The Building Conservation Directory 2022

PROFESS IONAL SERVI CES 1 35 C AT H E D R A L C O MM U N I C AT I O N S T H E B U I L D I N G C O N S E R VAT I O N D I R E C T O R Y 2 0 2 2 STONE SUPPLY AND THE PLANNING SYSTEM ELENI MAKRI T HE CONSERVATION of the historic environment relies on the supply of suitable materials to match the existing. When it comes to stone, many old quarries have long been abandoned and those still in use are often under threat, sometimes from the planning system itself. PRIMARY LEGISLATION AND THE STRATEGIC STONE STUDY In England, the supply of building and roofing stone for the conservation and repair of historic buildings falls under the legislation and governmental guidance on minerals. Primary legislation is provided by Section 97 of Part II of Schedule 5 and Schedule 9 to the Town and Country Planning Act 1990. This establishes the means for Mineral Planning Authorities (MPAs) to control minerals development. The relevant governmental policy is section 17 of the National Planning Policy Framework (NPPF) Facilitating the sustainable use of minerals . Minerals, and therefore stone extraction requires planning permission from the MPA, and in some cases additional permits and approvals, for example, ones from the Environment Agency and Natural England. The MPA in two-tier local government is the county council; otherwise, it’s the unitary authority or the national park authority. Back in 2004, the Symonds Report Planning for the Supply of Natural Building and Roofing Stone in England and Wales had identified serious problems in sourcing stone for historic building repairs. It recommended setting up a national database and for mineral authorities to identify and protect ‘heritage quarries.’ This report is the background to Section 17 of the NPPF and to the Strategic Stone Study (SSS), a national database developed by the British Geological Survey with the help of local geological and historic building experts, which was commissioned and funded by Historic England. The SSS uses a combination of fieldwork, historic records and maps, together with a representative range of historic structures to identify the most significant building stones in each English county. Freely available on the British Geological Survey website, it is of tremendous help to the stone specifier for two reasons: firstly, there is a vast number of stones used in the historic environment and these have now been largely catalogued along with representative historic buildings; and secondly it has made it possible to source new stone for repairs which matches both the appearance and the physical qualities of porosity and permeability of the original – the latter being important in avoiding different weathering of the new stone or even decay acceleration of the old. To understand how this all works in practice, the recent casework examples below may be helpful. NATURAL STONE SLATES OR ARTIFICIAL SUBSTITUTES? In 2020, listed building consent was sought for reroofing an 18th century pub in Aswarby, Lincolnshire, replacing its Collyweston stone slates with an artificial slate. The building, the Tally Ho Inn was listed Grade II and its original Collyweston slate roof coverings were mentioned in the list description. Despite this and against the strong objections submitted by the SPAB, the application was supported by the local authority’s conservation officer and approved. The overall justification for granting consent was the high cost of using matching stone replacements from existing quarries due to limited supply. According to the conservation officer’s report, the cost amounted to £400,000 and was twice as much as the market value of the listed building itself. The decision was taken in contradiction to Historic England’s Technical Advice Note 2005, Stone Slate Roofing which strongly advises against the use of artificial stone, as pointed out by the SPAB in its objections. Looking at the images in North Kesteven Council’s planning file, there can be no doubt that the roof of the listed building needed attention. However, The Grade II listed Tally Ho Inn, Aswarby: listed building consent was granted for replacing its natural Collyweston stone slates with artificial ones. (Photo: Chris Haythornthwaite)