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Traditional structures normally reflect their surroundings. Overwhelmingly, they are constructed of locally available building materials (Brown 2004, 23-4) and may vary widely over small distances, especially if altitude changes. Charles Gritzner (1974, 26) found that the altitudinal zonation of traditional dwellings in New Mexico was influenced not only by the easy availability of building materials but also by a number of less recognized factors, including "such fundamental economic laws as comparative advantage, primary resource use, diminishing returns and accessibility."

An excellent example of local geographical variation can be found in the junction zone between the Sierra Madre Occidental and the adjacent Central Plateau of Mexico. "The Sierra region has abundant forests, while often lacking sufficient water to permit easy manufacture of adobes or tiles. The other areas [the plateau] have abundant water, but the forests are distant" (Beals et al. 1944, 7). As a result wooden dwellings predominate in the sierra, while tile-roofed adobe buildings occur on the plateau, especially around Lake Patzcuaro on the plateau. Similarly sharp boundaries exist and are reported by Mason (1973, 24) for quite different buildings and locations in England. Structures made of exotic materials would not fit the definition of traditional buildings (i.e. accepted as a norm in a society), unless, of course, those materials became widely available at low cost and proved to be as efficient, or more so, than the already utilized objects.

Ethiopia offers still a third example of variations based upon availability of materials, but also reflects climatic differences and levels of technology. Naigzy Gebremedhin (1971, 110) suggests that three processes of construction have produced the traditional dwellings of the country. Weaving, using bamboo and grasses, is the building process employed primarily in the lowest altitudes. In the drier northern uplands, piling, the process employing adobe blocks, brick or stone, is encountered, whereas in the somewhat wetter central plateau between Gondar and Addis Ababa the method used is twining or tying, in which woody building materials are tied together by rope or other tying materials.

Sometimes the materials of construction are not natural building items, but rather are easily available and cheaply manufactured ones. Roofs, for example, may even be made of flattened metal oilcans. They are reported from as widely scattered locations as Alaska (Hoagland 1993, 67), India (Cooper and Dawson 1998, 40, 175), South Africa (Weller 1922, 7), and the Rio Grande valley of North America (Newton 1964, 24). Undoubtedly, they occur elsewhere.

Occasionally, the building materials have a close and unique connection to the inhabitants. The Kumbhara are a caste of potters in the Indian state of Orissa, who construct their dwellings out of terracotta pots. "The walls are fully built of stacked pots specially thrown for this purpose and arranged to form one huge thatched room. . . . Inside, this room is partitioned with more vessels into two or three living compartments. The terracotta walls provide remarkably effective insulation during the hot season and, when broken, double as niches" (Huyler 1982, 87). These buildings remind us that "construction techniques do not evolve or emerge in cultural isolation; they reflect and are based upon specific social and economic conditions" (Candee 1976, 55).

Among herders and hunters the use of animal products often makes up a significant component of the traditional dwelling. This is especially noticeable in those environments that offer little else in the way of building materials. Herders in desert, near-desert, and grassland areas use animal hides, as do Eskimos in summer - who in winter employ various parts of whales, walruses and other large Arctic animals.

Some of the earliest inhabited structures were either above or below ground (see Chapter 7). In the main, however, buildings are ground-fast, built from ground level upwards. This, of course, discounts the digging of cellars, often less than half the area of the building floors, and whatever modest excavation was necessary to level the ground; or the raising of a structure a foot or so to avoid the damp ground in humid areas and to facilitate air circulation under the structure to enhance cooling and retard deterioration.

The materials of construction can be divided into two major, basic groupings - earth materials and vegetative products. Each of these groupings can be further refined to sod, clay or mud, brick, and stone; and logs, timber, lumber, wattle, bamboo, tree leaves, grasses, and textiles. Each of these sub-divisions might be again ordered on the basis of the technology involved in their preparation and use. A third category, animal hides or skins, are used in a few places, but their use is quite restricted compared to earth materials or vegetative products.

In the middle and higher latitudes as people moved from early pits, dugouts and caves, it was only natural that they turned to materials that could be formed into structures to withstand cold temperatures, as well as keep unfriendly men and animals at bay. One of the most important of these materials was the earth itself. Even today, over a third of the world's population resides in structures made of mud (Moughtin 1985, 3). In India, as recently as the 1970s, 60% of all rural dwellings and almost a quarter of urban buildings were estimated to be of mud (Cain et al. 1975, 212).

The use of clay or mud as a building material is popularly believed to be restricted to dry environments, i.e. deserts or near deserts. While it is true that such materials dominate in these locations, mostly because of the scarcity of alternatives, mud and clay are also used in quite humid environments. Clay, earth or mud, in many parts of the world, is referred to as adobe, which is a modification of the Arabic word al-tob or mud. The use of an Arabic term is understandable because of the prominence of mud-walled and -roofed structures throughout the deserts of the Middle East. Introduced by the Spanish to Latin America, the term diffused to much of the rest of the world.

The principal advantages of adobe as a building material are its high insulation qualities, its extremely low cost because of wide availability, the fact that little skill is required to use it in its simplest forms, and its durability. As a result, adobe also lends itself easily to remodeling efforts (Bunting 1964, 2). Unfortunately, while in other respects a suitable building material, adobe is highly vulnerable to water damage. In humid areas the walls must be plastered and covered by a roof whose eaves extend some distance beyond the wall line in order to prevent back-splash and to guard against rising damp. In dry areas, where even the roof may be partially of adobe, three locations of potential damage are the roof itself, around roof drains where overflow and leakage may damage walls, and the lowest section of wall where back-splash can erode (Bunting 1976, 8). If wood beams are in contact with the adobe roof they are apt not to be watertight. Vigilant maintenance is required with all adobe structures.

In all areas, the walls may be constructed by building layer upon layer of mud in a method widely used in desert environments and sometimes referred to as "puddled adobe." The mud is mixed with a small amount of water and perhaps some binding material such as a little straw. In addition to providing dimensional stability, the straw allows the mud to dry more uniformly, thus minimizing shrinkage cracks (Miller 1949, 6). A ridge or mound of this is laid down as the base of the wall and allowed to dry thoroughly. Then the next layer is applied and allowed to dry. The procedure is repeated until the desired height is reached.

The same process is widely used in drier areas in its simplest mode. The layers of mud are built up with no restraining forms so that a natural, but pronounced, taper of the wall is created. At its base it may be three feet or more in thickness and just a few inches at its top. Such a taper is necessary for stability, but must be constantly monitored and repaired against erosion. Puddled adobe walls have been reported from the Sahara Desert and its margins in Africa, where it often is termed "swish" (Gardi 1973, 57; Rodger 1974, 103; Denyer 1978, 93), in western India on the margins of the Thar desert (Jain 1980), and it was a major method of construction in the dry areas of Mexico and the southwestern US before the arrival of the Spaniards (Bunting 1976, 9), and continuing in use long afterward.

One of the most unusual applications of mud building is practiced by the Musgum (Mousgoum), who reside astride the boundary between Cameroon and Chad. Their roughly conical houses can be as high as 30 feet. The basic structure is formed by strong reeds lashed together, over which the mud is laid. The smokehole opening at the apex is just a few inches in diameter and can be closed easily with a plate or pot when it rains. The single doorway, narrow at knee level and wider at shoulder height, has been described as resembling a keyhole (Gardi 1973, 91). Lumpy projections on the mud cone offer foot and hand holds that permit the owner to climb for repairs or to insert the rain pot.

Humid areas in which puddled mud walls occur today include England, especially in the east Midlands and in the county of Devon where it is identified as cob, the Brittany peninsula of France (Figure 5-1) and French-speaking Canada, where the French term torchi is used (Rushton 1979, 169; Meirion-Jones 1982, 52). "Cob is made of compacted clay and earth, bound with straw and moulded in various ways to form thick walls finished with lime plaster. It must be kept dry, so cob houses are always built on a stone or brick plinth. When the plaster comes off, the cob deteriorates very quickly" (Penoyre and Penoyre 1978, 54). Several reasons have been advanced for the emphasis on cob building in Devon. Among them are the suitable and abundant clay deposits, the poor timber resources for wood building and also the lack of much wood to be used as fuel for the making of fired brick.

A second method of employing mud, found in both dry and humid regions, utilizes a wooden form or shutter to restrain the mud and its binding elements until dry (Prussin 1970, 17). The form is then removed and raised to confine the next layer (Figure 5-2). Houses with walls made this way occur in many areas. The terms often applied to this method are tapia or pisé. Because this procedure greatly increases the density of the clay, pisé is stronger than either puddled adobe or even adobe brick (Norton 1986, 35). I have seen this technique being used in places as widely scattered as Morocco, Peru and

5-1. (above) Map of mud-walled houses in Brittany (drawing by Iraida Galdon Soler, based upon Meirion-Jones 1982, 52).

5-2. (right) Method used in Australia for constructing a pisé wall. Much the same procedure is followed in the rest of the world. The wooden form holds the mud mixture until solidified and the rammer or tamper compacts the material to remove air pockets, cracks and weakly bonded spaces (modified from Irving 1985,199).

5-3. A wooden tamper used to compact mud in pisé construction in northern Peru (photo by the author, 1985).

China. It is described by Carver (1981, 98-9) for northern Iberia, by Prussin (1970, 17) for Sudan, by Facey (l997, 90) for Saudi Arabia, for China by Knapp (1989, 70), for Bhutan by Denwood (1971, 26) and for South Africa by Frescura (1981).

The further modification of the pisé by extensive tamping, in which a heavy pounder (Figure 5-3) is used to compact the mud, removing all the air pockets and maximizing the mass, gives this method its other name, rammed earth. Occasionally a rammed-earth building is reported even from central or western Canada or the United States (Patty and Minium 1933, 6; Sculle 1989). The construction account in the journal Manufacturer and Builder is particularly valuable because it is a contemporary description of the process for 19th-century American farmers (Anonymous 1869a). Lest the technique of rammed earth be considered a new method, Nabokov (1981, 6) reminds us that it was used by 13th- and 14th-century Indians in southern Arizona.

If the earth contained a high lime content, it could be mixed with gravel and poured between the shutters a layer at a time. This variation of pisé construction, which required minimum tamping, is termed "mud concrete" or "poured adobe." It has been reported from Cache valley in northern Utah, and Iron County in southwestern Utah (Goss 1975, 211). One of the traits that make the Mormons of Utah interesting is the rapidity and success with which they adapted to different construction materials as they migrated westward. Coming from a humid, forested environment where frame houses were the norm, they built log cabins in Illinois, sod dugouts in Nebraska, and poured adobe and adobe-block houses in Utah.

Another major, and the most technically sophisticated, method of using mud is in the form of "adobe building blocks." In humid tropical areas the clay soil has a high iron and aluminum content and a reddish or yellowish color. It is referred to as laterite from the Latin word "later" meaning brick (Spence and Cook 1983, 36). This is a recognition of the fact that in a dry period the ground usually becomes extremely hard, and also due to the fact that when a block is cut out, or soft clay is molded into a form, it will dry to a hardness reminiscent of fired brick. The great advantage of adobe blocks is that they can be moved easier than the loose earth (Norton 1986, 30).

Again, two basic techniques are in use. The simplest, called "clay lump" or "toubes," is one in which the clay is formed by hand into a roughly rectangular block (Prussin 1970, 17). No form is used to shape the individual block. In the UK this technique is limited to East Anglia (Sandon 1977, 69: Penoyre and Penoyre 1978, 77; Egeland 1988, 10). Its limitation to that region is the result of two natural conditions: rainfall there is the lowest in all England and drying winds are the strongest (Addison 1986, 34). Clay lump also occurs widely in Africa (Gardi 1973, 53-61; Denyer 1978, 93). In tropical West Africa, the lateritic adobe is formed into cone-shaped lumps and tossed to the builder sitting astride the top of the wall (Blier 1994, 21, has an excellent photograph). The height to which these lumps can be thrown, without the use of scaffolding or ladders, determines the elevation of the wall (Moughtin 1964, 29).

A more sophisticated technique produces "adobe bricks." It requires packing the wet mud into a rectangular form. When partially dry, the mud has hardened sufficiently that the form can be removed. In both cases, clay lump and adobe brick, a thorough drying period of several days is required before the blocks are ready to be used. Even with thorough drying, adobe bricks may be susceptible to water erosion. In Utah a lime stucco may be used as an exterior plaster to combat this problem (Bonar 1983, 217).

As Mormons moved into the drier and less forested west of the US before the middle of the 19th century they came more and more to depend upon adobe brick as a building material (Fairbanks 1975; Jackson 1980). Initially they encountered several problems that they needed to overcome before adobe became their major early building material. First, they needed to find the proper mix of clay and sand. Often they used too much clay, which caused adobe bricks to shrink and crack badly upon drying. Sometimes they used too much sand and the bricks crumbled and failed to bond properly. Second, in their haste to provide shelter they used the bricks before they had thor oughly cured and the adobe would collapse when any weight was placed on it (Pitman 1973, 26).

Other techniques are used elsewhere. In urban areas of Afghanistan, where residents can afford the cost of more durable fired brick, it may be used as facing (Samizay 1974, 149). Fired brick is used in many places in smaller amounts to cap and protect the tops of adobe brick walls (Stanford 1975, 26). In Morocco a layer of reeds may be used instead.

The successful use of mud, of whatever method, requires the addition, or natural presence, of small amounts of binding materials. Straw or other fibers provide longitudinal strength. Lime, gravel, chalk, sand or dung are chemical strengthening agents without which the dried mud may crack and fall apart. In the American Southwest, early Spanish settlers employed a type of adobe bricks called terrones. They resembled the sod bricks of the Great Plains in being held together partly by grass roots. They were cut from the ground with a spade in a size larger than the typical sun-dried adobe brick (Motto 1973, 76).

The German-speaking Mennonites who migrated to the Russian areas north of the Black Sea in the 18th century are perhaps unique in having used all three main mud materials - puddled adobe, pisé, and adobe bricks - to construct their dwellings (Sherman 1974, 186). Coming from forest environments, in which timber supplied the basic building materials, the Mennonites were forced to adopt the mud-walling techniques of the Russians and Ukrainians, who were natives of the steppe grasslands where timber was lacking. These experiences stood the community in good stead when it moved to the largely treeless prairies of North America in the 19th century.

Another important earth building material was sod, or turf, used primarily in grassland areas where timber was scarce. Sod houses and sod dugouts were structures of necessity. Pioneer settlers on the Great Plains of the US found themselves in a vast, largely treeless land, where wood, their familiar building material, was mostly lacking. Because of the known severity of Plains winters they needed shelter, and needed it fast! The urgency was so great that pioneer settlers set about building sod structures even before they had identified that most critical of location elements, a dependable water supply. Often quarters laboriously constructed, had to be subsequently abandoned in order to use a more convenient water supply (Noble 1984, 1:72). Nevertheless, sod was the best solution. It was cheap and readily available. It required little skill to use and had excellent insulating qualities (Figure 5-4). One problem, however, was that about an acre

5-4. Sketch of a sod house, typical of the American Great Plains in the 19th century. Among the immigrant German settlers, the sod blocks were often referred to as kohlstein. The roof of this structure is of wooden boards covered by strips of sod (drawing by M. Margaret Geib).

of sod was needed to build a standard 12 x 14-foot dwelling (Welsh 1968, 41).

Sod houses in North America suffered from the same social stigma that log houses experienced. Although in both instances they were the mark of the pioneer in carving out settlements in what appeared to them to be a forbidding and dangerous wilderness, once the settlement frontier passed by, these structures lost any validity for many of the newcomers, as well as visitors. A traveling architect's account from 1876 is typical of such attitudes. Writing about sod structures in western Nebraska, he says "it is sometimes the result of necessity, but most frequently, we think, especially where allowed long to exist, the result of barbaric laziness" (Hussey 1876, 378).

The sod-house floor plan was usually a simple, one-room rectangle because these structures were normally thought of as temporary dwellings. Nevertheless, some continued to be occupied for more than a quarter century. A few carefully preserved examples can be seen throughout the Great Plains today, and in the 1970s five sod houses in western Kansas were still occupied (Oringderff 1976, 132).

The sod of Nebraska and the Dakotas was sometimes held to be superior by individuals from other regions. Such states "furnished a sod of a peculiarly hard and enduring character; not precisely equaled by anything our informants could discover in our own locality" (Roe 1970, 2). In many areas, a hipped roof of sod over boards or branches was preferred because it permitted all four walls to be built to the same height. In Kansas, however, a gable roof was the overwhelming favorite. Over 76% of all "soddies" there were so roofed (Oringderff 1976, 33).

Although sod was ubiquitous on the Great Plains and provided excellent insulation, sod structures were not without problems. Interi ors had poor light and ventilation because of few openings; dirt sifted down from the ceiling in dry periods; on rainy days and for several days thereafter the roof often leaked and dirt floors got muddy (Dick 1937, 114); insects, birds, mice and snakes found shelter in the sod (Drucker 1949, 361); and the heavy weight of sod roofs needed substantial support (Welsch 1968, 49). Despite these difficulties, "soddies" provided short-term shelter for thousands and many were occupied for decades.

In many parts of Europe, especially in western Scotland, Ireland, and Iceland, turf houses were constructed using methods similar to those of the North American pioneers. Turf blocks were cut and piled up like bricks or cut stone to form walls, and were also laid on timber frames to serve as roofing. In Ireland a related structure termed a moss house was made of turf and peat deposits by cutting and removing peat so that a large block was left at the center. The interior of the block was then scooped away, leaving the remaining turf and peat as free-standing walls into which a door and window were cut (Figure 5-5). Wooden posts were erected to support a roof frame and thatching (Megaw 1962, 90). The early Viking dwellings in Iceland were largely constructed of turf, supplemented by irregular blocks of volcanic rock. Interiors consisted of driftwood framing.

In the coastal southeastern United States, a burnt lime and seashell aggregate called tabby became a standard construction material for buildings, walls, and even roadways, under Spanish, French, and British colonial administrations. Its use in the New World derived from

5-5. Schematic floor plan of a "moss house." The trench and house interior are excavated, leaving the turf/mud wall standing freely in the center (drawing by Iraida Galdon-Soler, based upon Megaw 1962, 90).

African slaves assigned as construction workers, who knew its properties from their earlier residence in the Guinea Coast of West Africa (Jones 1985, 199). When tabby dries and cures it forms a rock-hard mass much like cement, so impenetrable that fortresses were sometimes built of the material.

The ultimate rock-hard earth building materials are brick and stone. If clay, rather than being used after natural drying, is subjected to baking and fusing temperatures in a closed kiln or oven, fired brick is the result, a much superior building material to mud or adobe. It is stronger and more durable; not subject to rapid erosion as adobe is; easier to handle than adobe; and has an equally high thermal insulation value and fire resistance (Rodger 1974, 103). "But brick is not the most satisfactory of materials in all times and places. In particular its slow release of heat makes it unsuited to areas where there is little nocturnal radiation" (Rose 1962, 262). Another major drawback is that a proper firing temperature is critical. Too high and the brick becomes brittle; too low and it tends to crumble and be susceptible to water erosion.

The quality of the soil materials used for the bricks is also important. If the proper balance of clay and sand is not present the brick will be soft regardless of firing temperature. Exposed to constantly high humidity, the bricks may prove generally unsatisfactory. This condition prevails in the lower Mississippi river valley and delta. In desert areas where brick should be superior to adobe it is not much used. The problem is lack of wood for fuel and the higher price of fired bricks because of the cost of fuel when it is available. Brickwork is usually categorized on the basis of how the individual bricks are placed in a wall. This is referred to as the brick's "bond." The bricks themselves are termed "stretchers" if the long side is exposed and "headers" if the end is exposed.

One large area over which brick became the construction material of choice for dwellings is the north European plain from the Netherlands to Poland. In this area forests were cleared early on and the great alluvial flood plains and deltas provided abundant clay deposits for brick making (Jones 1918, 21), as well as the fertile soils to support stable and prosperous agricultural settlement.

Greater status usually attaches to building in brick rather than in mud or wood. "In some parts of India and Africa, the proportion of brick-built homes in a village can be used as some sort of measure of its level of prosperity" (Spence and Cook 1983, 67). In the case of wood, this is probably because of the bricks' greater durability and fire resistance. In the case of mud, a brick structure's elevated status is perhaps because of its greater cost, more finished appearance, and the need for more skill in its construction. However, the prestige accorded to brick buildings in India also may reflect ancient Vedic traditions in which the type and quality of bricks allowed to be used were caste derived. The highest ranking castes (Brahmin and Kshatriya) could use fired bricks and mortar; middle castes (Vaishya and S'udra) were permitted only unfired bricks; and all the lower groups were restricted to wattle and daub and similar materials (Arya 2000, 17).

A danger exists for researchers to overestimate the use of bricks as opposed to wood, for example, because - as years pass - wood structures disappear at a greater rate than brick (Herman 1987). Thus, a researcher may find mostly older brick buildings in areas of study and fewer older wood ones, and come to the erroneous conclusion that brick was the major building material. Studies investigating the disappearance rate of traditional buildings are quite rare. Part of the problem is that many structures, especially of wood or mud, may leave virtually no trace after a short period of decay. A study of the disappearance on the Scioto river floodplain in a single county of Ohio of "agricultural structures" known to exist in 1915 showed fluctuations of the rate of disappearance from one every 24 months to one every 13 months (Noble and King 1989). While these rates may not be typical of the disappearance of all traditional structures even in Ohio, they do suggest that the rural built-landscape is in a constant state of change.

In North America, the dominance of brick is unlikely given the abundance and low cost of wood in earlier periods. The fewer but larger, well-built houses of the wealthy, which tend to be of brick, also are likely to survive at a higher rate (Lounsbury 1983, 186). Nevertheless, fired brick has a long history in the New World. In North America, almost as soon as European settlement began, kilns were constructed to supply fired brick. On Long Island bricks were being produced as early as 1628 (Weslager 1969, 130). By the 19th century, Haverstraw on the Hudson River may have been the largest brick making center in the world (DeNoyelles 1968, 3).

Many writers have commented on "English bricks," presumably brought over to the American continent in the early settlement period as ship ballast if not actual cargo. N.R. Ewan (1938) effectively demolished this idea. He noted that the term "English brick" refers in early documents not to imported bricks but to bricks made to a legal standard in North America as early as 1683. He further noted that the possibility of bringing bricks from the mother country becomes remote, if we consider shipping conditions of Colonization days. The ancient sailing ships of but 200 to 300 tons capacity, required many weary weeks in crossing and on their western trips were always overburdened with passengers and freight cargoes made up of goods indispensable to the existence of the new settlers. How improbable it would be that these vital necessities would be relegated to an embargo in favor of loading the small ships with common brick, which could be and were made here at a fraction of the cost of bringing them overseas. Little credence can be given to the many statements which claim the bricks were brought over "in ballast." The heavily loaded vessels needed no further weight than their own essential cargoes to keep them stable on the ocean voyage. Certainly, if bricks were ever shipped on these primitive boats, their value as ballast could have been used to better advantage on the eastern or "home" sailings, when few exports were being returned to Britain. (Ewan 1938, 12)

Before we reject entirely the idea of bricks imported to the New World as ship ballast, we need to consider the evidence presented by David Cohen (1992, 45-7), who quotes 17th-century documents that indicate that the Dutch in New Amsterdam did, in fact, contract with ship captains for such bricks.

Related to fired brick is the employment of wall cladding employing hung or mathematical tiles. Both of these techniques lie on the periphery of vernacular architecture. Hung tiles, first appearing in the latter part of the 17th century in England, most often occur in the southeastern counties on gable ends and sides exposed to weather to provide more effective protection than the brick and plaster infillings which were not entirely weatherproof. Mathematical tiles, invented late in the 18th century, were specially shaped without an overlapping surface so as to appear as fired bricks (Penoyre and Penoyre 1978, 29). They gave a brick-like appearance but evaded the brick tax in force from 1784 to 1850 (Addison 1986, 100). Used in southern England in the late 18th and first half of the 19th centuries, they were applied mostly to new construction. However, some traditional buildings, to follow fashion as well as to secure better weatherproofing, had these tiles added to earlier wooden frames (Smith, T. 1979).

The most durable earth building material is stone. Because of its weight, and hence the difficulty and cost of moving it very far, stone is used for dwellings within a few miles of its origin. Thus, a geological map showing building stone formations such as limestone, sandstone, and slate, is a useful guide to finding traditional stone structures. As Charles McRaven (1980, 11) notes, "stone is expensive if you count your time, cheap if you don't."

Fieldstones were probably the original stone materials used in vernacular construction. Mechanical weathering leaves many earth surfaces cluttered with rock fragments, which with some care can be piled up into walls (Perrin 1963-64, 137). Even without mortar to bind the rocks, walls can successfully be constructed in a technique called dry walling in which just the weight of the rocks holds them in place.

Careful fitting of the rocks is required and some kinds of rock are better than others. Angular sedimentary rocks with flat bedding and fault surfaces are best, with some limestones leading the way. The great advantage of dry-wall construction is that, if water penetrates, the effect on the wall is much less than in mortared walls (Denyer

Because of its weight and the time and skill required for its use, cut or finished stone building reflects regional prosperity. An example is provided by Stell (1965). "From the sixteenth century the Pennines of West Yorkshire, which had previously been sparsely populated, became more prosperous with the development of the woolen industry and new houses were required for the increased population." Not only was stone substituted for timber in building, many existing timber buildings were faced partly or entirely with stone.

Several factors in combination in the Mediterranean basin have worked to promote traditional building in stone in that region. They include a climate in which rainfall does not support extensive forest vegetation to supply timber; bedrock primarily of limestone and sandstone easy to quarry but hard enough to permit use in building; and a population that strained the limits of its resource base under traditional lifestyle levels. Simple stone structures are scattered from Spain and Morocco in the west across the islands and peninsulas of the center to the interiors of Syria, Jordan, and Palestine in the east (Walton 1962; Allen 1969; Ron 1977). The normal mode of stone building in these areas was the erection of circular plan, corbeled, domed or beehive-shaped houses.

The corbeled stone huts in Malta have been occupied or used continuously up to the present time. Built of a mixture of rough field boulders and dressed stone, they are huts for temporary shelter of farmers (Fsadni 1992, 9). Although merely temporary field huts, the girna exhibit all the basic characteristics of more permanent stone dwellings encountered throughout the Mediterranean basin (Walton 1962, 33). Furthermore, many stone structures, both in Malta and elsewhere, after being used for human shelter continued to serve as housing for smaller livestock such as goats, sheep, and pigs (Fsadni

Floor plans of stone structures vary from circular to oval, rectangular and square, and in overall form from beehive to barrel vault to pyramid roofed. The corbeled roof is covered by small stones, and even finer gravel. Because corbeled stone huts occur most often in limestone areas, they are frequently associated with, or are in proximity to, extensive cave dwellings. This is true in southern Spain, the Greek islands, and in the heel of southern Italy.

In this latter area, corbeled stone construction reached a high degree of craftsmanship (Allen 1969). In addition to the simple field huts, magnificent dome- and cone-shaped trulli were built. The base may be rectangular, oval or circular, and the construction material limestone or the softer volcanic tufa. Several local terms are used to identify these corbeled structures, but trulli is the term most widely applied and known. "The word trullo (sing.) comes from the Greek troullos and its Latin derivative trullus, meaning a building with a conical summit" (Castellano 1964, 7). An alternative term, chipuro, is of Greek origin and means "guardian of the cultivated fields," indicating the rural origin of this type of building. Later-built trulli and the bulk of those remaining today are found in villages (Branch 1966, 96).

The method of construction is that of an inner and outer wall with earth and small stone filler between. Until the 1930s, Italian farmers were not wealthy enough to hire builders and they constructed their own trulli. Since then, however, builders have come to the fore and designs have become gradually more sophisticated, but less traditional. The basic form has not changed much, however, indicating local satisfaction and acceptance. In many instances, the later trulli have multiple cones and rectangular stone and masonry additions.

Rectangular stone buildings, in which the domed or vaulted ceiling is encased in a flat stone and masonry roof, are characteristic of Palestine (Amiry and Tamari 1989, 17-25). The walls are thick to support the heavy roof. The two-story structure functions as a housebarn,

5-6. An isometric drawing of a Palestinian stone housebarn. The family living space is termed the mastabeh. Mud bins for food storage divide and separate the rooms. A lower level houses livestock and agricultural equipment (based upon Amiry and Tamari 1989, 22).

with animals and equipment occupying the lower level and living quarters above (Figure 5-6).

Building with cobblestone is an outgrowth and refinement of fieldstone construction. Placing small cobbles in a bed of mortar to create a wall "bears a strong resemblance to the best flintwork and masonry of coursed kidney cobbles" in southeastern England (Perrin 1963-64, 1314). Cobblestone building reached its apogee in northeastern North America, where the combination of continental glaciation to break up and transport rock fragments, and subsequent stream and lake smoothing, provided an abundant supply of suitable stones (Noble and Coffey 1986) (Figure 5-7). The middle of the 19th century was the period of maximum development of cobblestone architecture (Figure 5-8), which centered on upstate New York (Schmidt 1966, 2). The age and location of cobblestone buildings supports the thesis that surplus "stone masons, thrown out of work by the completion of the Erie Canal, found employment in building cobblestone structures . . . Furthermore, the distribution of these structures reflects those areas in

5-7. Cobblestone building in the 19th century was influenced by continental glaciation and by erosional smoothing of stones by lake and river water action. The large area of cobblestone construction in New York State is also related to the number of masons attracted to the area by the building of the Erie Canal and other canals. The Laurentian Shield, an area of old, hard rock, furnished the source area for the cobbles carried south by the glacier (from Noble and Coffey, 1986).

5-8. Cobblestone structures were built in New York State in the 19th century, largely between 1830 and 1855. Only two dwellings are known from after the Civil War, one built in 1872 and the other in 1879.

which the final phases of canal construction took place in New York State" (Noble and Coffey 1986, 45).

The earliest structures were not actually of cobbles, but of "field-stones of varying colors, sizes and shapes" (Edward 1978, 33). By general definition, a cobble is a stone that can be held comfortably in one hand (Shelgren et al. 1978, 1). Furthermore, true cobblestone architecture requires the stone to be embedded in a cement mortar primarily in horizontal rows. The natural cement, which makes up almost half the volume of a cobblestone wall, was also directly related to canal construction. The quest for a bonding material, which was needed in enormous quantities for the construction of the canals, resulted in the discovery in 1818 in central New York of vast deposits of natural cement rock (Lesley 1972, 13-14).

Carl Schmidt, the acknowledged authority on cobblestone architecture, proposed a three-period development (1958, 231). The early period was one of mixed stone colors and sizes, and the horizontal courses were somewhat irregular. The middle period brought more standardized sizes and better color matching, and the introduction of water-smoothed stones (Figure 5-9). Finally, the late period saw a con-

5-9. Examples of cobblestone walling. The regularity in size and shape of the cobbles is typical of the middle period of cobblestone building, when the stones were laid in courses defined by ridges of cement (drawing by M. Margaret Geib).

centration on small stones and almost machine regularity in the horizontal courses.

From a heartland in central New York, cobblestone building advanced westward into Michigan and Wisconsin by the 1840s and 1850s (Frasch 1965, 8). By 1870, census returns listed 25 cobblestone houses in the city of Beloit, the center of Wisconsin cobblestone building (Shedd 1974, 21). Another concentration of cobblestone structures may be found around Paris, Ontario, and a smaller collection at Baldwin, north of Toronto (Rempel 1967, 282). Even before the Civil War brought a cessation of cobblestone building, the popularity of such construction had begun to wane. Perhaps this was a result of a depletion in the availability of the stones, or a lack of young masons to replace the dwindling numbers of the original canal workers, both of which conditions would have resulted in increased costs of construction. The final chapter on cobblestone architecture research has not yet been written.

Another area of stone construction, but of quite different type, occurs in southern Brittany. "Walling formed entirely of orthostats, large flat vertical slabs of stone with their lower ends embedded in the ground, has been recorded in six locations, but only in south Finistère, in the region between Concarneau and Pont-Aven, do large numbers of buildings incorporating this type of walling survive" (Meirion-Jones 1982, 53).

These houses of upright stones are in the same area in which the famous, upright megaliths of Carnac occur. The Carnac monuments undoubtedly served as a model for the use of the stone in house construction. The granite stone slabs are about two and a half meters long and stand upright with the lowest half-meter buried in the ground. Exterior walls are of orthostatic rock, except for the gable wall, which incorporates the heavy granite chimney. Hipped roofs are often encountered since they accommodate the orthostatic stones better than the gable form. Also, the houses are only a single story in elevation because of the difficulty of building upon the upright stones (Meirion-Jones 1982, 54). Cut stone, rubble, and pisé close any gaps in the orthostone walls.

In a few instances, stone in the form of slabs of slate has been used for walling of timber-frame houses (Figure 5-10). In the area around Boppart along the Rhine in Germany, slate, often cut into flat diamond shapes, is a particularly common wall material (Stevenson 1880, 190). Slate as a walling material also occurs in Belgium and in England in Cornwall, Devon, and especially in the Lake District (Brown 1982, 205; Addison 1986, 40). Much later, long after the period of traditional building, slate was used in the early 20th century as wall covering in parts of Pennsylvania and eastern Ohio, and perhaps elsewhere. However, slate walling never reached the popularity of slate roofing.

One quite unusual combination of stone materials is encountered in the Lake District, where wooden lintels are covered first by a course of thin slates projecting from the face of the wall, and then by a

5-10. Slate-sided houses are found in several districts of Europe. This example is located near Brussels, Belgium. Only the gable wall facing the direction of prevailing wind and storm has been slated. Decorative patterns are formed by using slates of differing color (photo by the author, 1984).

course of cobblestones holding the slate in place (Denyer 1991, 151). The slate course acts as a deflector of rainwater. Slate also forms a unique structural element in some buildings in this region by forming crow steps, stepped slate projections lined up along the roof gable edge (Denyer 1991, 155).

One special kind of earth material used for a seasonal or temporary dwelling is snow (Schwatka 1883). The word igloo is the general Eskimo word for a dwelling, employed as we might use the word house (Ray 1960, 13). However, the term has come to have a more specific application in much of the world outside polar areas, meaning a dome-shaped snow and ice structure. The snow-block dome of the Eskimo igloo "encloses the greatest volume for the smallest surface area of any wide-based structure, so heat losses through wind-chill are minimized." The snow is "cut into rectangular blocks and laid not in horizontal corners, but spirally. This means that the structure is self-supporting throughout, the blocks being trimmed to slope inwards until the key-block is added from outside" (Duly 1979, 54-5).

The igloo was limited in most polar areas for use only as a temporary expedient, and to central North America as a seasonal habitation, but because of its unique use of materials and its attractive and efficient form it is more widely appreciated than its numbers and limited use warrants. Most arctic peoples used partly excavated houses, often with whalebone frames in the winter and animal-skin tents in summer (Cranstone 1980, 488-9). A wide variety of largely non-descript structures served as shelter in spring and autumn transitional periods (Lee and Reinhardt 2003).

Everywhere and at all times, earth materials used in traditional building tend to be employed either in a natural state, such as mud, sod or snow, or after minimal processing, such as brick (both adobe and fired), cut stone, or slate. In societies of lower technological levels, earth materials provide dimensional strength, and because of their lighter weight often dominate a structure's upper areas and roof covering. Because of their more or less ubiquitous nature and low cost, earth materials have been widely employed in all parts of the world, especially in communities that have lower technological levels. However, this circumstance should not be equated with lack of craftsmanship. The mud lump, conical roofs of the Musgum huts; the delicate patterns etched into adobe walls by many tribes in South Africa; and the terracotta pot walls of the Khumbara caste in India, to cite just a few instances, offer examples to refute this negative view of craftsmanship.

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How To Have A Perfect Boating Experience

How To Have A Perfect Boating Experience

Lets start by identifying what exactly certain boats are. Sometimes the terminology can get lost on beginners, so well look at some of the most common boats and what theyre called. These boats are exactly what the name implies. They are meant to be used for fishing. Most fishing boats are powered by outboard motors, and many also have a trolling motor mounted on the bow. Bass boats can be made of aluminium or fibreglass.

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