page_title: Dry stone
section_title: Construction
hierarchical_section_title: Dry stone / Construction
caption_attribution_description: Il·lustracions d'Andrés Marín Jarque per a l'exposició permanent "Secà i Muntanya" del Museu Valencià d'Etnologia. S'il·lustren els escenaris del medi rural i el procés (treball) mitjançant el qual s'aprofita este espai.
context_page_description: Dry stone, sometimes called drystack or, in Scotland, drystane, is a building method by which structures are constructed from stones without any mortar to bind them together. Dry stone structures are stable because of their construction method, which is characterized by the presence of a load-bearing façade of carefully selected interlocking stones.
  Dry stone construction is best known in the context of stone walls, traditionally used for the boundaries of fields and churchyards, or as retaining walls for terracing, but dry stone sculptures, buildings, bridges, and other structures also exist.
  The art of dry stone walling was inscribed in 2018 on the UNESCO representative list of the intangible cultural heritage of humanity, for dry stone walls in countries such as France, Greece, Italy, Slovenia, Croatia, Switzerland and Spain.
context_section_description: A wall's style and method of construction will vary, depending on the type of stone available, its intended use and local tradition. Most older walls are constructed from stones and boulders cleared from the fields during preparation for agriculture (field stones) but many also from stone quarried nearby. For modern walls, quarried stone is almost always used. The type of wall built will depend on the nature of the stones available.
  One type of wall is called a "double" wall and is constructed by placing two rows of stones along the boundary to be walled. The foundation stones are ideally set into the ground so as to rest firmly on the subsoil. The rows are composed of large flattish stones, diminishing in size as the wall rises. Smaller stones may be used as chocks in areas where the natural stone shape is more rounded. The walls are built up to the desired height layer-by-layer (course by course) and, at intervals, large tie-stones or through stones are placed which span both faces of the wall and sometimes project. These have the effect of bonding what would otherwise be two thin walls leaning against each other, greatly increasing the strength of the wall. Diminishing the width of the wall as it gets higher, as traditionally done in Britain, also strengthens the wall considerably. The voids between the facing stones are carefully packed with smaller stones (filling, hearting).
  The final layer on the top of the wall also consists of large stones, called capstones, coping stones or copes. As with the tie stones, the capstones span the entire width of the wall and prevent it breaking apart. In some areas, such as South Wales, there is a tradition of placing the coping stones on a final layer of flat stones slightly wider than the top of the wall proper (coverbands).
  In addition to gates a wall may contain smaller purposely built gaps for the passage or control of wildlife and livestock such as sheep. The smaller holes usually no more than 8 inches in height are called 'Bolt Holes' or 'Smoots'. Larger ones may be between eighteen and 24 inches in height, these are called a 'Cripple Hole'.
  Boulder walls are a type of single wall in which the wall consists primarily of large boulders, around which smaller stones are placed. Single walls work best with large, flatter stones. Ideally, the largest stones are being placed at the bottom and the whole wall tapers toward the top. Sometimes a row of capstones completes the top of a wall, with the long rectangular side of each capstone perpendicular to the wall alignment.
  Galloway dykes consist of a base of double-wall construction or larger boulders with single-wall construction above. They appear to be rickety, with many holes, which deters livestock (and people) from attempting to cross them. These dykes are principally found in locations with exceptionally high winds, where a solid wall might be at risk of being unsettled by the buffeting. The porous nature of the wall significantly reduces wind force but takes greater skill to construct. They are also found in grazing areas where they are used to maximize the utility of the available stones (where ploughing was not turning up ever more stones).
  Another variation is the Cornish hedge or Welsh clawdd, which is a stone-clad earth bank topped by turf, scrub, or trees and characterised by a strict inward-curved batter (the slope of the "hedge"). As with many other varieties of wall, the height is the same as the width of the base, and the top is half the base width.
  Different regions have made minor modifications to the general method of construction—sometimes because of limitations of building material available, but also to create a look that is distinctive for that area. Whichever method is used to build a dry stone wall, considerable skill is required. Correcting any mistakes invariably means disassembling down to the level of the error. Selection of the correct stone for every position in the wall makes an enormous difference to the lifetime of the finished product, and a skilled waller will take time making the selection.
  As 
caption: Construction work on dry stone. Illustration of the Valencian Museum of Ethnology
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