Dry Stone Walling Techniques
One can get a rough idea of where walls are likely to be found in Britain by looking at a geological map. Bear in mind though, the complicating effects of glaciation throughout large parts of Britain. In some areas, notably much of Ireland, glacial drift has covered up the useful walling stone. In other areas, poor underlying stone has been augmented by glacially transported boulders, so that walls have been built where, by the map, none would be expected.The design of a typical dry stone wall is shown below, with the parts named in accordance with widespread north-of-England usage. The ways in which regional and local styles differ from this general pattern are described further below, and in.Southern and Central EnglandIf one thinks of walling in southern or central England, it is the landscape of the Cotswolds which probably springs to mind. Stone walls and buildings of warm russet-brown or golden grey which, according to J B Priestley, know ‘the trick of keeping the lost sunlight of centuries glimmering upon them’.
The stone is Jurassic limestone. The thicker oolitic beds supply freestone for building purposes while the shelly limestones, which break irregularly, provide ragstone for the walls. Most Cotswold walling stone is quarried from a layer about a foot below the subsoil, under which lies the more regularly jointed building stone. In the past, large areas of quarry land would be scalped of their overburden to expose the wall stone layer, which would be allowed to weather and break up naturally with the winter frosts. In some places, as at the top of Bredon Hill, the walling stone is fairly hard and rings when hit, but elsewhere it is soft or grades into sandstone and sounds dead when tapped. The harder the stone the better it lasts, and experienced Cotswold wallers can tell at a glance where their supply has been quarried and what its qualities are.The Cotswolds form only one part of the Jurassic limestone belt which runs right across southern and central England from the Isle of Purbeck north-northeast to the Cleveland Hills.
Each district shows the influence of local variations in its stone. The belt is quite narrow, trailing off into clay vales along the southern or eastern dip slopes. This is the country where, as Hawkes (1951) puts it, ‘the sudden appearance of walls instead of hedges catches the eye’. Nowhere is the change more dramatic than in Lincolnshire, where the limestone of Lincoln Edge is only a few miles wide, and there is an abrupt change from hedges with brick and timber buildings, to the geometrical austerity of dry stone walling.There are other areas of walls in central and southern England. In northwest Leicestershire, the hills of Charnwood Forest, rising unexpectedly from the Midlands plain, and representing an island of Precambrian granitic, volcanic and slaty rocks, possess rough and intractable boulder walls which seem more in keeping with the mountainous West than with the fertile and gentle country around.The rocks of the Mendips, while not nearly as ancient as those of Charnwood Forest, form an equally interesting inlier among the more recent deposits of this region.
The Mendips consist largely of a plateau of Carboniferous limestone, the oldest widely occurring limestone in Britain, out of which protrude a few higher hills of the older and more resistant Old Red Sandstone. Limestone dominates the walls, although sections built of sandstone or breccia occur where these rocks form the uppermost strata.
The breccia is known locally as ‘pudding-stone’, a term also used locally to describe any round stone, in order to distinguish it from the more angular ‘ploughshare’ stones. Many of the fields are large, with the north-south walls often higher than those orientated east-west.At first glance the walls look very much like those of the Craven district of Yorkshire, but on close inspection their stones are rougher and more irregular, and they lack throughs and topstones.‘Bonders’ are used instead of throughs, extending part way through the wall. These are important because Mendip wallers tend to place many of the face stones with their long edges running along rather into the wall, known elsewhere as ‘traced’ stones. Short stones used with their long edges into the wall are known as ‘key stones’. Mendip walls are built with little batter; only about 2″ (50mm) for a 4-4’6″ (1.2-1.37m) high wall.In general, walls throughout southern and central England lack the variety of openings and other structures which are such a feature of Pennine, Lakeland and Scottish walls. The PenninesThe Pennines represent the single greatest expanse of walled country in England. Rising from the Midlands plain on the Staffordshire-Derbyshire border, the moors run northward for about 140 miles (220km) to the Tyne Gap.
Immediately beyond, the Cheviots continue the uplands to the Border Country, while to the west the Howgill Fells create a link with the Lake District. The bedrock geology of this area is fairly simple, but contains striking contrasts.
In the Craven district of northwest Yorkshire and in the central Peak District of Derbyshire, Carboniferous limestone forms the surface cover. Here, over the ages, water and ice have carved a landscape of glaring white crags and scars where underground watercourses abound but there are few surface streams and pools. Farther south and east, through most of South and West Yorkshire and Derbyshire, the relatively acid and impervious shales and sandstones of the Millstone Grit and Coal Measures cap the geological series. Here, and over wide areas throughout the Pennines where glacial deposits obscure the solid geology, drainage is poor, and surface waterlogging has encouraged the formation of sombre heather moors or blanket peat bogs.The limestone pavements of North Yorkshire and Lancashire are of particular interest, both for their geological and botanical importance, and as unique landscape features.
These pavements, along with those of Cumbria and elsewhere in the British Isles comprise the world’s most important areas of limestone pavement, so there are also international responsibilities to protect them. Throughout history they have formed tempting sources of stone supply, with widespread damage in Victorian and more recent times for walling and building, and for ornamental and rockery stone. While the importance of limestone pavements is now recognised, damage by deliberate removal of stone or inappropriate management is still taking place.Most limestone pavements are now protected by Limestone Pavement Orders, which have the effect of prohibiting the removal or disturbance of limestone. Many important pavements are also included within Special Areas for Conservation (SACs) under the EU Habitats Directive, and these and other pavements will also have been notified as Sites of Special Scientific Interest. However, statutory protection needs to be accompanied by a reduction in demand for limestone pavement stone, which is sold as ‘water-worn stone’, ‘Cumberland limestone’ or ‘Westmorland limestone’. Local authorities are being urged not to specify such stone in their landscaping schemes, and to ensure that it is not used in any development which requires planning permission.
For further information see the advice leaflet Limestone Pavement (Countryside Commission, 1998)The walls of the Pennines reflect the geological contrasts in their colouration: clean grey-white in the limestone districts, dappled at their border with other formations, and sooty grey or dark brown elsewhere. The colour alone is enough to tell you when you have crossed the Craven Fault near Stockdale or along the Settle-Malham road, revealing the alternating grits and limestones in the Yoredale series as the walls change from dark to light to dark again as they mount the upper slopes of Wensleydale.In the northern Pennines the rocks are mostly of Carboniferous age, as in the Craven and Peak district, but here the strata are more mixed than further south and the walls are more often of varied sandstones and shales than of limestone. Of quite different origin are the walls of the Whin Sill, a dark blue-grey dolerite which was injected into the Carboniferous beds at a later date. The most famous of these walls is Hadrian’s, which takes advantage of the craggy scarp formed by the Whin Sill along most of its north side. Parts of the Roman structure can be seen among the rough rubble of the farm walls which run back from its line. Also distinct from the main mass of sedimentary rocks of this region are the Cheviots: a granitic core surrounded by a dissected dome of lavas of Devonian age, from above which the Carboniferous rocks have eroded. The Lake DistrictThe Lake District, a compact area only about 30 miles (48km) across, contains a surprising number of different rock types and corresponding styles of walling.
Starting with the oldest formations in the district, the Skiddaw Slates of the northern peaks, one finds walls of dark or occasionally greenish fissile slates and flags. The wall shown has only one row of throughs, but two rows may be used depending on the height.Between Keswick and Ambleside, in a broad zone which includes the most rugged part of the district, the Borrowdale Volcanics form a varied group of erosion-resistant massive lavas and tuffs.
The granite and granophytes of Ennerdale and Eskdale produce walls of similar type but a warm mottled pink. The volcanic walls are generally similar in design to those of slate but are generally coarser and more massive.The Lake District is full of historically fascinating examples of stonework, and the ‘cyclopean’ walls of huge boulders found in several locations. The most impressive of these, about 9′ (2.7m) high on the downhill side with enormous footings, runs beside the road near Far Kiln Bank above the Duddon Valley.The southern part of the Lake District is made up of Silurian slates, which includes shales and flags as well as true slates.
These resemble the Skiddaw slates in their well-marked cleavage which produces slabs for walling.Where the Coniston and Brathay Flags occur at the boundary of the Silurian slates and Borrowdale Volcanics, roughly quarried. Many examples can be found around Coniston, Hawkshead and Ambleside.Around the edges of the Cumbrian dome other newer rocks occur which connect Lake District walls with those of the Pennines and the Carlisle area. Carboniferous limestone around Furness, in the area south of Kendal and elsewhere is used to build silvery-grey walls, quite similar to those found farther east in Yorkshire. New Red Sandstones occur on the coast around St. Bees and in the long tongue of the Eden Valley, where the walls are rusty red and often of shaped and well-bedded blocks, while between here and the limestone area is a narrow belt of Coal Measure gritstone walls.
WalesGwynedd contains most of the oldest rocks in Wales, and has a complex geology, reflected in the range of wall types. Slates, granite and volcanic rocks, Carboniferous limestone and Precambrian schists and gneisses lie in a series of roughly parallel bands broken by intrusive dykes and sills. The topography is determined by many factors. Most of Anglesey belies the diversity of its bedrock, as it is a fairly uniform, low plateau which represents an old wave-cut platform.
How To Install Dry Walling
Around Snowdonia, volcanic rocks play a significant part in the strong relief. The area is a syncline of resistant rocks, sculpted by glaciation.
Similar rocks occur also in Cader Idris to the south, while the intervening Harlech Dome consists of more highly eroded Cambrian grits and slates.Volcanic rocks dominate the walled farmsteads of the western foothills of Snowdonia and parts of the passes of Llanberis, Nant Ffrancon and their surroundings. The stone is tough and coarse, the walls rough and grey.
Along the roadside in this area every sort of combination can be seen: rough volcanic copings on slate walls, slate copings on slate walls, slate copings on rubble walls, and slate fences.Moving south, the wide expanse of central Wales with its rounded hills of mudstones, shales and slates, is mainly hedged or fenced, although quite often a wall separates the rough grazing of the highest land from the better fields below. The South Wales valleys present a scene more like that of the southern Pennines than of the rest of Wales, with grits and flags predominating The South WestAll linear enclosing features which are not regular masonry are termed ‘hedges’ in mid and west Cornwall.
Through much of this area the hedges are earth banks faced with stone or turf, but on the high downs and moors, especially in the far west, dry stone hedges are common. The distinction between dry and mortared walls and earth banks is sometimes blurred. On the moors and country around Camelford some dry stonework is found, but most of the hedges are of earth capped with stone or brushwood. A type of hedge found occasionally in the Boscastle-Tintagel district consists of stonework only one stone thick. Similar walls are common on the Isles of Scilly, and it’s said by islanders on the ‘off’ islands that such walls were built so that gaps could easily be made as necessary to take boats across the fields to the sea, when sea conditions prevented boats being launched from their usual landing.It is the stone- or turf-faced bank which is most commonly called a hedge in other parts of the South West, and this forms the dominant type of fence whether or not it is crowned with a row of living shrubs.
The design and construction of stone-faced banks is described in of this handbook., and is the type specified in county road-widening schemes. It may be built in two forms, depending mainly on whether the stone used is slate or granite. The use of quarried slate from north Cornish mines has been extended into the western granite areas, although this is unpopular with local craftsmen who prefer the traditional material, however expensive. For farm hedges the source of stone is normally the land being cleared. The stone is mainly fragments cleared from the surface or within a plough’s depth.
Dry Stone Walling Techniques And Traditions
‘Pop’ or decomposed granite is favoured because it has flat surfaces. Blue elvan, which is also found, is harder to handle because it is smooth and splinters into wedge-shaped pieces. Around Truro most of the stone used is spar, supplemented by waste stone from the tin and copper mines, and by quarried granite. The latter is an expensive material which is usually laid in even courses of smooth blocks to produce a neat, masonry-like finish. Unfortunately these blocks bind poorly with each other and with the earth packing and tend to slump, especially when placed with their long edges along rather than into the bank.The last two rows of slate hedges are normally built in the herringbone pattern, also called ‘Jack and Jill’ or ‘Darby and Joan’. This helps to use up the small pieces which are cracked from the ‘raisers’ or face stones during building, and provide a good rooting medium for the turf capping. Herringbone work is usually found wherever thin, splintery stone must be used which would otherwise be hard to manage.Many stone hedgers prefer to use rough horizontal coursing of largely untrimmed material, which some claim is stronger, as well as being easier and faster to build.
The Devon ‘chip and block’ style is similar, being roughly graded from biggest at the bottom to smallest at the top, but there is a mixture of small stones (chips) and large stones (blocks) within each layer. Great emphasis is given to placing the stones tightly together and to wedging them from behind so that they sit well and bond with the earth packing. Cornish work often shows considerably more earth between the stones on the face of the wall.The diagram shows different sides of the same gate end, near Dartington, South Devon. One side was built in ‘chip and block’ by a local worker, the other by a Cornishman.
Both sides use mainly river-washed boulders, but the Devonian has knocked off most of the rounded faces to bring them into line with the overall batter. In chip and block the stones can be placed either vertically or horizontally, and the joints are broken depending on the alignment of the stones.In the South West, free-standing dry stone walls are mainly limited to the edges of the granite moorlands: Dartmoor, Bodmin Moor, the Land’s End area and the Isles of Scilly especially. They are of rough horizontal courses, sometimes topped with turf. In a few places granite walls give way to more geologically diverse structures, such as at Sticklepath on the north edge of Dartmoor, where there is a remarkable range of rock types, colours and textures in the local walls.
Free-standing walls and stone hedges are sometimes intermixed in a boundary, and derelict free-standing walls tend to be rebuilt as stone hedges.One sort of wall which is unlikely to ever need repair is that found in a few places on Dartmoor, but most spectacularly near Zennor, in the far west of Cornwall. Some of the tiny fields are enclosed with single rows of enormous granite boulders or ‘grounders’, rising up to 7′ (2.1m) from the ground. These are relics of ancient enclosure, and may be 2,000 years old or more.Although such walls seem primitive, is part of the same enclosure system. Scotland and the Isle of ManThe ‘drystane dykes’ or dry stone walls of Scotland are found in various forms which reflect the type and size of stone in the locality, as well as particular walling techniques, both local and more widely adopted.The typical dry stone wall is called a ‘double dyke’, because it has two faces, which are packed with hearting and joined with throughstones as in other areas. Almost any type of stone can be used, but whinstone double dykes are more common through central Scotland, with sandstone dykes found in certain districts in Southern Scotland and the west coast. The dimensions given below were as specified by the Stewartry Drystane Dyking Committee (Rainsford-Hannay, 1972).
The subdivision dyke is the normal height wall for field enclosure, with the higher march dyke used as a boundary to the great estates.Whinstone is rough and makes a varied and irregular dyke such as that shown, containing ordinary ‘doubling’ stones, big face stones called ‘blonks’, and wedge- shaped stones called ‘nickers’, which help bring the course up to level. Pinnings are used in the face. Sandstone dykes are often cut and trimmed and built up in evenly graded courses. Face stones are placed with long edges into rather than along the wall.
A feature is the use of the. One third of the wall’s weight is supposed to be in the coverband and coping. The throughstones and coverband project about 2″ (50mm), to help dissuade sheep from jumping the wall.As with north of England walls, Scottish double dykes are well supplied with openings for the use of the shepherd and trapper. Construction methods are the same as in England for ‘pen holes’ (rabbit smoots) and ‘double water pens’ (water smoots). Than the top, rather than being rectangular.More common in Scotland than elsewhere in Britain is the single dyke, built of stonework one stone thick. This developed as a way of using large stones, and is particularly suited to coarse textured stone, such as granite, which have less tendency to slide than does smoother stone. Single dyking is quick to build and repair, and it’s said that sheep are discouraged from trying to climb anything which they can see through.The half-dyke or Galloway dyke is a style found only in Scotland, and was developed in order to use a variety of medium and large shaped stones, with little hearting available.
The larger stones are too large to use as the lower part of a double wall, as they would make a wall which would be too wide to fill with the hearting available. Instead, in reverse to the normal procedure, the smaller stones are used in the lower part of the wall as a double dyke, and the large stones are used above as single stonework.Galloway seems to have long been a centre for innovations in dyking methods, and for the export of men and ideas to other areas. The walls of the Isle of Man, mostly about 220 years old, were extensively rebuilt and improved in the 1880s by a pair of Galloway dykers with the help of local labour (Rainsford-Hannay, 1972). Slate-faced banks are prevalent but there are granite walls on the high ground and sandstone elsewhere. The sandstone outcrops in good-sized slabs, 2-3″ (50-75mm) thick, which are used both in free-standing walls and in stone-faced banks. Some of the banking takes advantage of the slightly wedged shape of these slabs,.
The weight of the bank drives the stones tightly together. The banks are up to 7′ (2.1m) high, about 6′ (1.8m) wide at the base and 4′ (1.2m) wide at the top, and topped with turf.In the north of the Isle of Man, the easiest stone to find is water-worn beach cobbles. These are too smooth to use in the ordinary way, but are placed edgeways-in to face earth banks.
The Manx free-standing walls are coped with very big slabs, tilted at about 15˚ from the horizontal.The dykes of Aberdeenshire are designed primarily to fence cattle, and are found in two forms. The rough rubble or ‘dump and hole’ dyke uses field stones, mostly untrimmed, or with just their corners knocked off. The ‘course dyke’ uses trimmed quarry stones in neat courses.The stones are massive, about 1′ (300mm) thick, and usually of granite.
The dykes need not be as tall as sheep fences, but they are carefully built with no projections which cattle could rub against. Normally no throughstones are used, as stones which could span the wall would be too heavy to lift. The preferred topstones cross the full width of the dyke, and are trimmed so they don’t project.As well as fully dressed boundary walls, the Dunecht area has many rough rubble walls which appear at first glance to be ill considered heaps of boulders, until one examines the care with which individual stones are placed. A few miles to the north and west, the Cluny style takes over, which features low walls of small stones backed by post and wire fences.
Still farther west, near Grantown-on-Spey, Morayshire, the dykes have a mixture of large and small stones in the courses, and are topped by rough upright boulders.Whatever the local variation, these walls often require considerable work with the hammer and stone drill. More skill and patience are required to split granite, even roughly, than are demanded by most other stones. IrelandEvans (1957) characterises Irish walls as untidy and cyclopean, mainly of rough glacial boulders and ‘lacking the precision of those of north England or the Cotswold country’. This may be due to the absence of easily-shaped material, such as Jurassic limestone, as well as to the glacial drift covering so much of the country. Although a few walls or ‘ditches’, as all dykes or raised banks are termed in Ireland, are of Iron Age origin, most are from the comparatively recent enclosures of the 18th and early 19th centuries. Throughout the lowland farming country, the hedged ditch is common, sometimes with a ‘sheugh’ or open drain running alongside it.Throughout the south and central part of the country dry stone ditches, where they occur, are usually built with far less batter and far more stones than their Scottish counterparts, according to Rainsford-Hannay (1972), who goes on to list their typical dimensions as 6′ (1.8m) high and 4′ (1.2m) wide at the base.
Throughstones are scarce but are sometimes used, and the coping may be of mortar, sod or small stones placed haphazardly on top.In the west of County Clare and Galway, especially in the Burren district with its tiny fields and its outcrops of Carboniferous limestone, single-thickness walls are built which closely resemble the Galloway single dyke in style and function. Sheep are said not to attempt to climb these unsteady-looking structures. Single walls are also found around fields on stony moraines and drift-boulder hillsides.
In east Galway the limestone ditches are built double to a height of about 2′ (600mm), carefully levelled off and finished with a lacework of single boulders to a total height of 4-5′ (1.2-1.5m). It would seem that this similarity between Galway and Galloway walls may not be coincidental, and that the Irish version may well have been introduced by incoming landlords and their agents.
Mortar or cement is used in the coping of many Irish walls, and is sometimes used as a facing. The Irish language has no word for dry stone waller, but wallers are referred to as masons. This may also indicate the relatively recent importation of the craft into most parts of the country.On Rathlin Island off the coast of Antrim, the idea of the unsteady-looking wall has been taken to the extreme. It’s said that animals give them a wide berth once having learnt that they collapse almost at a touch. At the other extreme are the 10′ (3m) high demesne walls running for miles around the big estates which, according to Evans (1957), are ‘famine walls’ built by destitute labourers in return for a pittance from the landowner.DerryLondonderry has examples of ancient head-walls, built to separate early farm enclosures from the rough outfields. These are known locally as ‘Danish fences’ and consist of irregularly piled stone slabs with standing stones set at intervals. Similar walls, and walls with many stones set vertically or diagonally are found elsewhere in Ulster and Munster.
Often only the standing stones remain today, buried in the peat which has overwhelmed the ancient fields. Elsewhere in Ireland there are walls of almost indeterminate age: the wide granite accretion or clearance walls of the Mourne Mountains, for instance, which closely resemble those of the Lake District and Aberdeenshire.Some of the walls of the Aran Islands have ‘phantom gates’, which had to be taken down every time cattle were herded through a field, and grazing plots four fields in from the road were not unknown. The reason for this laborious design was, apparently, less the lack of wood and metal but more the need to keep the wind from getting into the fields (Evans, 1957). Similar structures were also used in Connemara and County Clare. © Copyright 2019 The Conservation Volunteers (TCV).
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