Building and Roofing Stone Mineral Planning Factsheet
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Mineral Planning Factsheet Building and roofing stone This factsheet pro- atural stone is the traditional building tions since that time. Nevertheless many for- vides an overview Nmaterial of Britain and the built environ- mer important sources of building stone are no of natural build- ment is perhaps the most visible aspect of longer available. ing and roofing our cultural heritage. Stone has been used stone, including for building and roofing purposes in the UK Building and roofing stones, including slate, slate, extraction for over two thousand years and the geo- are naturally-occurring rocks of igneous, sedi- in the UK. It forms logical diversity of the country has meant that mentary or metamorphic origin which are suf- part of a series the variety of the rock types used is prob- ficiently consolidated to enable them to be cut, on economically ably unmatched anywhere else in the world. shaped, or split into blocks or slabs for use as important minerals Production and usage of these stones has seen walling, paving or roofing materials in the con- that are extracted a decline, since the highpoint of the industry in struction of buildings and other structures, such in Britain and is pri- the late 19th century, largely because of compe- as bridges and monuments. The term natural marily intended to tition from cheaper manufactured alternatives stone does not include manufactured products, inform the land-use such as brick, concrete, glass and steel. As a such as reconstituted stone or ‘artificial’ stone, planning process. result many local sources of building stone are although these are an increasingly important no longer available. However, natural stone sector of the building materials market. Flint, March 2007 used in prestige buildings did not experience a chert and other similar materials such as con- serious decline until the 1960s when wartime cretions and boulders can be important build- reconstruction was tailing off and economic ing materials and flint was perhaps used more conditions were more difficult. That period widely than any single building stone. However, did, however, see planning requirements to most of these materials are produced adventi- maintain the local character of settlements, tiously as part of other mineral extraction or particularly in Conservation Areas, create a other operations and therefore do not come demand for local stone, which could no lon- within the strict consideration of this factsheet. ger be supplied by recovery from demolition. Consequently there has been a noticeable A wide range of rock types is used as sources increase in interest in, and demand for, natural of building stone, including sedimentary lime- stone and the prospects for the industry remain stones and sandstones, metamorphic slates and buoyant. Overall the diversity of supply of local marbles, and some igneous rocks, principally Limestone, Corallian stones has increased as planning permissions granite. The suitability of a stone for building Group, Abbotsbury have been granted for new extraction opera- purposes depends not only on factors such as strength and durability, and commercial con- siderations such as the size of block or slab that can be extracted, but importantly on its aesthetic qualities, such as colour and texture. Other factors, including bed thickness, ability to polish, and ease of carving or sawing for mouldings, may also be important. Dark, rough dressed, thinly bedded sandstone slabs impart local character to the vernacular buildings in the countryside of the Pennines, Mid Wales and Cornwall but contrasts with the use of precisely cut blocks of pale granite or Portland Limestone, with considerable bed thickness, that convey monolithic grandeur in prestige buildings in our major towns and cities. Demand Two principal markets – new buildings and the repair of historic buildings drive demand for natural stone products. 1 Natural Stone Mineral Planning Factsheet Building and roofing stone 2 New building involves both maintaining The conservation market is of increasing vernacular styles using materials that are importance. Britain has a large stock of historic compatible with traditional local building stone structures that are protected by legisla- practices, and also use in contemporary tion that demands like-for-like replacement design requirements including internal and of stone wherever possible in conservation external decoration. New build also includes projects. These structures form an important prestige or major commercial projects that part of the nation’s cultural heritage and are may have a high-tech, contemporary or clas- a considerable attraction for both domestic sical style where the use of a specific stone and foreign tourists. In essence they provide may be a secondary consideration, but can a ‘Sense of Place’ and character to our cities, add to the proposed architectural impact. towns and villages. The need to protect, restore It is worthwhile remembering that every and conserve these buildings, many of which stone building was at one stage a new build are built of indigenous stones, is recognised project. Imported stone has had a share of as an essential objective in the maintenance of the prestige, new build market, since at least landscape and townscape. the 11th Century when Caen stone became widely used, for example in Canterbury, Natural building and roofing stone products Winchester and Norwich cathedrals. are rocks quarried for the purpose of obtaining blocks or slabs that can be used non-dressed 2 Repair and maintenance of historic buildings or subsequently dressed (shaped), riven (split) and structures requires the use of mate- or sawn (ashlared) for general building. They rial from the original or compatible quarry include: sources. Stone cladding – material quarried, split, sawn The market for stone for new building is small and/or polished for non-load bearing walling and specialised but relatively buoyant. Small material. builders have seen a growth in demand for Kerbstone – stone used for edging roads and individually designed stone-built houses that footpaths can command premium prices. However, the Setts – stone roughly squared for roads and ‘Poundbury effect’ has also created demand paving for a wider variety of building materials, Flagstone – quarried, sawn and split (riven) including stone, throughout the house con- specifically for flooring or paving. struction industry. Even where brick or recon- Slate – rock with a pronounced metamorphic stituted block is the main walling material, (slatey) cleavage allowing it to be split into details such as steps and lintels may be in thin sheets - principally for roofing but also for natural stone. In addition, stone is becom- decorative cladding and monumental use. ing more widely used in boundary walls and Stone slate – rock (other than slate) that is thin- street furniture. ly bedded and fissile (easily split or riven into thin slabs) and quarried specifically for roofing Indigenous natural stone is also highly sought purposes (includes both limestones and sand- after for large and prestigious building projects stones). such as the new Scottish Parliament Buildings Monumental stone – rock quarried cut, split, (Kemnay granite), the Wales Millennium Centre dressed or polished specifically for use in mon- (Welsh slate) in Cardiff and ‘The Collection’, uments, gravestones or memorial tablets. Lincoln’s new county museum (Ancaster lime- Decorative stone – rock quarried, sawn, worked stone). The Welsh roofing slate industry, is an and polished for (architectural) ornamentation example, of an industry which was built on the – fireplaces, stone mouldings basis of a low cost, high volume product that Marble – geologists only apply this term to has now become a low volume, high value- limestones that have been altered by meta- added item, competing successfully with the morphism. However, the building trade uses Cumbrian green slate industry for prestigious the term to include any limestone that is hard roofing and building projects. enough to provide a polished surface. Building stone Natural Stone 2 Mineral Planning Factsheet Building and roofing stone Walling stone – rock quarried for non-dressed Sales of building and roofing stone are shown (rubble) or lightly dressed blocks. in Table 2, some figures have had to be esti- Rockery stone – stone cobbles and boulders, of mated because selected information is confi- varied lithological composition, used in land- dential. These figures should be treated with scaping and gardening. some caution, as they are believed to over estimate production, particularly with respect Supply to igneous rock. An independent study by the Symonds Group on Planning for the supply of Quarries primarily producing building stone natural building and roofing stone in England in Britain vary significantly in size and output. and Wales (2004) on behalf of the Office of the They range from relatively large operations Deputy Prime Minister (ODPM) concluded that with areas in excess of 50 ha and operating annual production of building and roofing stone continuously with a high face, to very small in England and Wales during the period 1999 to sites less that 0.5 ha in extent and worked very 2001 was approximately 714 000 tonnes. occasionally to recover stone from a single thin bed. In addition, almost all crushed rock Two major groups of resources dominate the aggregate quarries produce, or can produce, supply of building stone in Great Britain; the building stone as an ancillary product. Larger various