Building Materials and Construction Methods Wood and Related Materials

After earth materials, vegetation is the main source of building resources, and wood in various forms and modes is the most important component. Indeed, wood is undoubtedly the most widely used construction material for dwellings around the world (Lazistan and Michalov 1971).

Logs, which in simplest form are nothing more than tree trunks stripped of branches and cut into convenient lengths, are widely used in colder, humid climates throughout the world where appropriate forest resources occur. Log building is not a mode widely found in forested tropical areas for four major reasons. First, although the forest stand is very dense, it is composed of a very large number of disparate species. Second, the forest floor is often waterlogged and covered with a tangle of exposed roots. Third, suitable draft animals have not been available to transport the heavy timbers. Elephants, animals more often of the much drier tropical savanna, have been domesticated and employed in the commercial timber industry only in restricted areas of South and Southeast Asia. Finally, because of the abundance of light forest products and because temperatures are uniformly warm, negating the need for tightly fitted buildings, these lighter materials suffice.

In most of the humid tropical world then, the traditional house is built of light vegetative materials (Figure 6-1). The framework is of small wooden or bamboo poles with a thatched roof. In some instances the temperatures are so uniformly warm that walls are entirely dispensed with. This was the case with the chickee hut of the Seminole Indians in southern Florida. A similar structure prevailed in the Pacific island of Samoa, where light wall screens, when needed because of cold winds or driving rain, could be lowered into place (Hiroa 1930, 8). Mosquito netting provided protection at night.

Protect Wooden Barn From Rain

6-1. Bamboo structural members, thatch roof, and palm-leaf panels make up this tropical house from Tamilnadu, India. Unless the roof is soon repaired, the house will not be inhabitable for much longer (photo by the author, 1976).

The environmental conditions in most of the tropical world encourage building with easily available light materials. Constantly warm temperatures mean buildings do not have to shield against cold, but constant rainfall means humidity is always high and wood deteriorates quickly, and termites, beetles and woodworms present a constant menace to buildings. Houses, therefore, are utilitarian and functional, not decorative, and not meant to last very long. When the roof, the most critical element, begins to leak, the structure is abandoned if quick repairs cannot be effected (Feeley-Harnik 1980, 566).

Bamboo represents the most widely used structural material of the tropics, while palm fronds and leaves are the most often used surface commodities. As late as the 1980s, housing censuses in the costal lowlands of Colombia and Ecuador showed between a quarter and three-quarters of all rural homes to be of bamboo construction (Parsons 1991, 150).

Not all tropical construction utilized bamboo, however. In the Niger River delta, the common material used in traditional building is the raffia palm, whose use illustrates nicely the ingenuity of builders and the care they take not to waste any part of the plant. The midribs of the fronds are used as poles, or spilt into slats. The leaves "could be folded over two or three of these slats, and pinned into position with smaller bamboo skewers to form tile-like roofing mats." The outer bark of the tree is stripped into long sinews for tying material (Jones 1984,

96). When done, other raffia palms could be tapped for palm wine to celebrate the event. More often than not, vines and fibers of various kinds secure the structure rather than nails or pegs (Figure 6-2).

The combination of earth materials in the form of "daub," and vegetation in the form of interwoven light shoots of wood or "wattle," is one of the most common and most successful building modes both in the tropics and the mid-latitudes. Studies of wattle and daub are prevalent in the British Isles, where this form of building prevailed for a long time. Bruce Walker (1977, 7) provides a list of terms by which wattle-and-daub building is known in various parts of the British Isles: clay and wattle, clay and mott, stake and rice, clout and clay, clam staff and daub, stab and rice, daub and stower, rice and stower, riddle and daub, keeber and mott, caber and daub, strae and rake, rod and daub, split and daub, and cat and clay. The existence of such a profusion of terms not only emphasizes the former isolation of areas, but how widely practiced the technique was. Still a different term "stud and mud" is widely used in the African tropics (Mcintosh 1974, 161).

6-2. A thatched roof and bamboo dwelling preserved in the Tanzania Village Museum, Dar-es-Salaam. The upper decorative wall screen composed of short lengths of bamboo aids ventilation and structural integrity (photo by the author, 1975).

6-3. Wattle construction is one of the simplest and cheapest forms of building. The mud daub may be plastered on one or both sides of the wattle. These wattle panels are on a building in the Cloppenburg Open-Air Museum, Germany (photo by the author, 1983).

In a widely used procedure, "the wattle or hurdle work was formed by vertical stakes, each fitted into a hole or slot in one horizontal and sprung into a groove or another hole in the other member of the framework. With these were interwoven pliable material, such as longer rods, osiers, reeds or thin strips of oak" (Wood 1965, 225). The daub consisted of a "marly clay mixed to the right consistency with water" and then augmented and strengthened with the "binding fibrous element of chopped straw, hay, cow hair, and perhaps cow-dung" (Singleton 1952, 77; Wood 1965, 212 & 225). This mixture was then plastered onto each side of the wattle (Figure 6-3), which was then placed as a panel for wall filling. The final step was to provide two or three coats of limewash, "thus adding an egg-shell protection to the rather soft daub. ... It is due almost entirely to this lime-wash that so much wattle and daub still survives" in the UK (Singleton 1952, 77).

Not only was wattle-and-daub construction common in the UK, it was used across France, Germany (Figure 6-3), and Poland into Russia (Jorre 1967, 82) and to the southeast in the Balkans (Brunvand 1974, 11). Hungarian settlers, familiar with the technique, introduced it to the Canadian Prairie provinces (Stalfelt-Szabo and Szabo 1979, 229).

Wattle-and-daub construction is also reported from the cool highlands of Ethiopia (Brooke 1959, 69), southern Tanzania (McKim 1985) and the High Veld and humid coastal areas of South Africa (Frescura 1981), where a variety of beehive-, cylindrical- and rectangular-plan structures all have this type of wall construction. Wattle-and-daub building is also common both in the rest of tropical Africa and all across tropical Asia. Here, rather than inset wattle-and-daub panels, the entire wall is of unified construction (Norton 1986, 25). Amini Mturi (1984, 185-6) lists wattle-and-daub building as one of the three kinds of construction common to all Africa south of the Sudanic grassland. Because rainfall is high in the humid tropics, decay of wattle-and-daub walls is reasonably rapid, resulting primarily from rain splash and capillary moisture movement. This produces undercutting and collapse of segments of the clay. Termite inroads are also a serious problem causing decay (Mcintosh 1974, 162-3).

Wattle-and-daub construction is also used widely in the Latin American tropics. In the Amazon it is referred to as torroes (Sternberg 1984). In Colombia, and less often in Ecuador, the wattle is guadua, a type of giant bamboo. The exterior is coated with mud, sometimes mixed with straw and whitewashed (Parsons 1991, 141). The use of laths as an anchor for clay or plaster in later building is an outgrowth of the earlier wattle-and-daub technique. In vernacular structures it can be encountered not only in Latin America but also in such widely dispersed areas as the Indus valley of Pakistan (Lari 1989, 36), and Ukrainian and Hungarian settlements of Alberta and Saskatchewan, Canada (Lehr 1973, 11; Stalfelt-Szabo and Szabo 1979, 229).

A different, but still basically similar, technique is employed on the island of Zanzibar. A frame of strong but lightweight vertical and horizontal poles is erected with a roof of coconut leaves. The horizontal members placed both inside and out, form open squares about four inches in size. To this is plastered the mud (Skolle 1962-63, 16).

Light vegetable materials also are used for building in the desert and near-desert area of the American southwest and northern Mexico. The almost universally employed material is the tough stalks of the ocotillo shrub, although willow shoots may be used when available (Lehmer 1939, 185). Frequently, adobe may be applied to these in a "wattle-and-daub" technique, but the stalks and shoots, collectively called jacal, is such a significant component of the building that its name is even used to refer to the entire structure itself, as well as the frame poles. The English-language word "jacal" is borrowed from the Spanish, who earlier had modified it from the Aztec word xacalli, which means "adobe house or house of straw, a humble dwelling." The English word shack is derived from the same origin (Bracken and Redway 1956, 44; Noble 1984, 1:84).

Another light, often poorly and hurriedly-built, structure carries the name shanty. This term derives from a French-Canadian phrase used to describe the building where lumberjacks were fed and housed, une cambuse de chantier (Mann and Skinulis 1979, 16). These words were anglicized to camboose shanty. Camboose means a provision or store room, hence its use in a further changed form to designate the living quarters of the crew on a freight train, the caboose.

Chantier, a lumber yard, became the name for the pile of wood thrown together by early French-Canadians as a rough dwelling, or in English a shanty. With a change in spelling and in a further derogatory use, shanty added to Irish was applied in the United States in the 19th century to designate poorly paid Irish laborers who lived in temporary shacks and moved from construction job to job.

One of the world's most unusual building materials is the baled hay used in the Sandhills of Nebraska. Here, in an environment without wood, where considerable depths of loose sand are covered by grass, the hay harvested from the grass and compressed into bales proved to be the only available building material in the early days of settlement (Welsch 1970). Today, at least 20 of these dwellings are still occupied, most protected by a stucco covering (Noble 1984, 2:115).

In humid areas of the mid-latitudes, because of the abundance of timber, log building became a standard mode of construction. Although the basic technology of log construction is quite simple, great variety exists in the finished product. As Paul Klammer (1963, 13) noted:

Log cabins are like fingerprints. At first glance they all look alike, but closer study shows that each one differs from all others. The differences are due mainly to the kinds of logs that are used, to the workmanship of the builder, and to his good taste-or possibly that of his wife.

The great coniferous forest zone of Europe, from the Alps and Carpathians in the south, eastward across northern Siberia, and northward across the Baltic Sea to Fenno-Scandinavia, possesses the world's largest concentration of log structures. From this great heartland, log building techniques were exported to North America by the Fenno-Scandinavians and Germanic peoples, and diffused there primarily by the Scots-Irish and Germans (Morgan 1990). Furthermore, John Winberry (1974) holds that German miners were responsible for the introduction of log building into Mexico. From Mexico, it was introduced into the southwestern United States by Hispanic settlers (Gritzner 1971, 54 & 60). Just how important log building was throughout the United States can be gauged from research performed by John Morgan (1986, 41), who found that in Humphreys County, Tennessee, 72% of all houses were of log as were virtually all (96%) barns. Other areas in Appalachia offer similar concentrations (Eller 1979, 96; Langsam and Johnson 1985, 14).

Scholars who spend most of their time investigating structures in areas largely devoid of log buildings seem to have little appreciation of those structures, dismissing them with distaste and scorn. An otherwise excellent article (Carson et al. 1981, 139-40) reveals this orientation:

For those who built them [primitive shelters including log] they were temporary, improvised expedients; for such improvisations are as remote to a study of regional vernacular building traditions in the American colonies as charcoal burners' huts and shepherds' skali are to the investigation of vernacular architecture in Great Britain and northern Europe. Much more important - then and now - were the buildings that came immediately afterward.

Even left in their natural round shape, logs can be used for building by laying them horizontally, one atop the other, and securing the corners. Because of the round shape, the logs protrude into the interior and considerable additional material must be added to create flush walls and to fill the "chinks" between logs. This can be small stones, mortar, bark, and narrow pieces of wood, earth or sphagnum moss. Marilyn Brinkman and William Morgan (1982, 45) have expanded the list to include clay mixed with animal manure, animal hair, straw, grass, gunnysacks, and even newspapers. Nailing narrow pieces of scrap lumber to cover the interstices (much like the later and more elegant battens of board-and-batten lumber frame walls, but horizontally rather than vertically) has been reported in Georgia by Wilbur Zelinsky (1953, 174). Gabrille Lanier and Bernard Herman (1997, 74) even mention whole fired bricks as chinking material in the Mid-Atlantic area.

By hewing the logs somewhat, they can be made to fit more tightly, and the amount of chinking, which often needs to be replaced annually, greatly reduced. The savings in both time and effort could be substantial. Roger Welsch (1980, 319) estimated that "the average size log house has approximately V mile of linear chinking."

Examining log houses in Alberta, William Wonders and Mark Rasmussen (1980, 202) identified three major methods of weather-proofing a log wall. The commonest method was to use logs in round and to stuff the space between with sphagnum moss covered with lime plaster. Throughout North America, sphagnum moss has been the most widely used material for chinking.

A second method, used in Ukrainian log houses in Alberta, employed square-hewn logs to which thin lath strips were nailed, with a plaster finish applied over the lath (Figure 6-4). Among Scandinavians, logs were so carefully fitted that little chinking was needed, but thin clapboards often covered the exterior. Eventually, the Finns and Scandinavians became so adept at fitting logs that chinking was virtually eliminated (Carter 1984) They did this by scooping out the underside of each log to fit the upper curved profile of the log beneath. The same technique was reported by Ronald Olson (1927, 25) to be practiced by Athabascan Indians around Cook Inlet in northwestern North America.

Vertical Chinking

6-4. Both vertical and horizontal round logs form the walls of this Ukrainian house near Senkiw, Manitoba. Light willow sticks are attached to the logs to act as an anchor for the mud daub, much of which has already disappeared (photo by the author, 1983).

Eliminating wide spaces of chinking also made the log houses warmer, since the chinking materials usually had a lower insulation value than the logs. Hewing the log to produce more or less flat sides removed the outer sap wood "which rots easily and is prone to insect damage, it removed excess weight, left flat surfaces to work from, and helped keep rain out by offering a place for the water to drip off at the bottom of each log" (McRaven 1985, 48). Hewing requires only two simple tools, a felling ax and either a broadax or an adze. In southern Indiana and elsewhere, "most frequently the bark was not even removed from the top and the bottom surfaces" (Roberts 1976, 439).

The integrity of log buildings depends upon the method by which the corners are held in place. A wide variety of corner notches accomplish this task (Kniffen 1969). The simplest, oldest and most widely used technique is that of saddle notching, in which the logs are left in the round and the notch is cut with an ax in both the top and bottom, or better, just in the bottom to retard decay from the water collecting in a top-cut notch (Figure 6-5). Hungarian settlers on the Canadian prairies, previously unused to log construction, found saddle notching so simple that they used it exclusively (Stalfelt-Szabo and Szabo 1979, 228).

Log Notching Techniques
Saddle notching V-notches
Full dovelailin^ Half dovetailing

6-5. Examples of log corner notching. Saddle, V-notch, and half dovetail are the most commonly encountered (from Kniffen 1969,2-5. Courtesy of the Pioneer America Society).

V notches require more careful work: "If the log remains in the round, the visible end of the log is pear-shaped. If the log is squared, the end resembles the gabled end of a house, and the process is often called 'roof topping'" (Figure 6-5). Squared logs have greater aesthetic appeal even in rough, remote areas. Charles Martin (1984, 19) reports that in remote areas of Appalachia "a hewn-log dwelling was called a house, whereas a round-log dwelling was called a cabin."

Dovetail notches are even more complicated, and for ease and speed of construction were often cut in North America by sawing (Roberts 1976, 440). The half dovetail has a flat bottom and the full dovetail a sloping one (Figure 6-5). Dovetail notches drain well because of their outward sloping surfaces, and hence are long lived.

All of these notches were introduced into North America from source areas in Fenno-Scandinavia, the Germanic Alps, and the Bohemia-Carpathian area (Kniffen and Glassie 1966, 63; Jordan and Kilpinen 1990, 11). In addition to the notch types just reviewed, dozens of others of more sophisticated or intricate design exist. The magnificently illustrated volume, The Craft of Log Building, by Herman Phleps (1982) contains no less than 45 drawings of different corner notches. They are especially diverse in the countries around the Baltic Sea.

Among the lesser-known notches are the diamond notch, probably derived from the hexagonal notch of Central Sweden (Jordan et al. 1986-87). Square and half notches are originally from the Bohemian-Carpathian highlands and from south-central Sweden (Jordan and Kilpinen 1990). Various tooth notches characterize Fenno-Scandinavia (Erixon 1937; Kaups 1976, 13-14). Such notches also occur in the Carpathians, but are rare in North America. They do appear in the Finnish areas of northern Michigan, Wisconsin and Minnesota, and the mountainous parts of Idaho and Montana. Diamond notches in North America occur primarily in North Carolina and southern Virginia. In contrast, square notches are widely distributed throughout North America (Jordan and Kilpinen 1990, 8).

A major difficulty with horizontal log building is how to fill in the upper gable wall when the structure is capped by a gable roof, the easiest roof to build over a rectangular building. Using logs presents two problems. First, the increasing height makes the heavy logs difficult to handle. Second, the logs do not lock in place with corner notches. To avoid these problems, log builders in North America used hewn planks to close the gable triangle. Germans placed the gable planks vertically (Brumbaugh 1933, 22) and Scots-Irish placed them horizontally.

Most log houses are just one or one-and-a-half stories high and contain one, two or three small rooms. Size limitations were in large part dictated by the length of the timber, its weight - which makes handling onerous (Perrin 1967, 22 & 28) - and the difficulty of joining timbers to accommodate larger floor plans. Michael Ann Williams (1984, 36) notes that the late 19th-century log houses in Cherokee County, North Carolina are smaller than pre-Civil War ones. The explanation is that "as sawn lumber became cheaper and more available, the family desiring a larger house would have preferred frame construction." One of the major reasons for the popularity in Texas of the dogtrot cabin was that it permitted use of shorter lengths of timber in the construction of its two separated enclosed parts. The drier climate of Texas supported only trees of modest growth (Collier 1979, 30).

In other instances where only shorter lengths of log are available, an alternative method of construction is used (Lebreton 1982, 435-6). It has been used, and studied, most widely in French-speaking areas, but also occurs in the Ukraine, Poland, and northern United States around the upper Great Lakes. In Canada, this mode of building spread from French-speaking areas in the east, ultimately all the way to the Pacific coast. Because of its French connection, and the fact that many studies are in English, but by non-French speakers, considerable confusion persists in the English definition of the terms (Richardson 1973). Because available logs are short, corner notching is not practical. To solve this difficulty, the horizontal logs are tenoned or pointed at each end to fit into slots cut into the vertical posts (De Julio 1996) (Figure 6-6). This type of construction is generally referred

6-6. Piece-sur-piece method of log construction. Corner and side posts are grooved to accept the tenons of the horizontal logs. The posts fit into notches and holes in both plate and sill for an extremely tight fit (drawing by M. Margaret Geib).

6-6. Piece-sur-piece method of log construction. Corner and side posts are

Piece Sur Piece Construction

to as piece-sur-piece, but in Canada it is also variously called Hudson Bay style, Red River frame, or Manitoba frame.

A variation of French-inspired log building was employed early on in French Canada and throughout the Great Lakes-Mississippi River drainage area. Termed poteaux-en-terre or pieux-en-terre, depending upon the diameter of the wood, the posts, logs, or poles were used vertically rather than horizontally. In the early period of North American settlement by the French, the posts were driven directly into the ground, as a palisade would be. "When built of rot-resisting cedar, they made a sound and fairly permanent structure" (Peterson 1941, 217). Later on, a wooden sill was introduced to support the base of the vertical members in a mode called poteaux-sur-sole. By 1800 houses of these two types comprised more than 97% of the buildings of St. Louis, Missouri (Richardson 1973, 81).

In central and western Europe, when supplies of timber neared exhaustion and cost consequently increased, buildings began to shift to a construction system of half timbering, in which only the major structural members were wood and the walling was of earth materials, most often mud or brick nogging. Even before this happened, a farmstead emphasis on small, special function buildings, rather than large, multipurpose dwellings and barns was the result of depletion of the supply of large logs (Atkinson 1969, 50). Of course, smaller logs were also easier to handle.

An unusual mode of log and mortar wall building involves the stacking of stove-length or cordwood pieces of soft wood, usually white cedar, in a bed of mortar. Several obviously appropriate names have been given to this method: stovewood architecture (Tishler 1979, 1982), cordwood construction (Airhart 1976), stackwood house (Anonymous 1977; Anonymous 1978), stackwall building (Alberta OSERP 1976), log end (Roy 1977), and log-butt architecture (Rempel 1967). Examples of stovewood buildings occur across northern United States and southern Canada from Minnesota to New Brunswick, and William Tishler has identified examples from Norway and Sweden (1982, 126 & 132-3). The concentration of such buildings in Wisconsin has been particularly well studied (Perrin 1963).

Stovewood building differs from other types of horizontal log construction (Figure 6-7)

because the walls are made from logs cut into short uniform sections and stacked perpendicular to the length of each wall ... In many instances the logs were split lengthwise into smaller sections. These pieces were then laid in a bed of wet lime mortar that enclosed each chunk of wood but left the cut ends exposed. The resulting wall resembled a pile of neatly stacked firewood. (Tishler 1979, 28)

6-7. Part of a stovewood wall in a house on the Door Peninsula, Wisconsin. The two-foot-long lengths of wood have been split and placed in a bed of mortar. The timber frame carries numerous ax marks made when hewing occurred (photo by the author, 1980).

Stovewood construction permits the use of short lengths of wood, which would otherwise be useful only as fuel. Furthermore, lengths of varying diameters can be employed together. The wood must be of the same species and very well seasoned and dry. The insulation value of stackwood is higher than that of brick, masonry or concrete block (Roy 1977, 29-30). Another important advantage is that building a house can be done easily by one person (Airhart 1976, 55). Balancing these advantages somewhat is the great time required to assemble, debark, and lay up the huge number of wood pieces involved (Jenkins 1923, 19). Twice as much wood is needed as in horizontal log construction (Airhart 1976, 56). Also, exposed log ends decay faster than logs with sides exposed (Mann and Skinulis 1979, 153).

Timber-frame structures in the British Isles followed one of two methods of framing - cruck or box. Cruck framing, which involved the use of an entire tree trunk, or at least a major branch of a very large tree, was typical of early frame construction in the north and west of the United Kingdom. An enormous amount of research has been done on cruck framing, which survives mostly only in Great Britain. One reason why this and other research on traditional buildings and construction methods has proved so fruitful is that in the British Isles, wars - which are so destructive to traditional buildings - have been largely lacking since the 17th century. Devastation in World War II occurred mainly in the cities.

More than 3,000 cruck buildings can be identified in England and Wales (Alcock 1981, 6). "Over most of western Britain, at all except the highest social levels, the earliest surviving buildings are cruck structures" (Alcock 1981,1), with a particularly high concentration on the North York Moors (Smith, P. 1979, 3). In addition to Great Britain, cruck trusses occur widely in France, reported in Brittany (Meirion-Jones 1981, 39-55), in the Dordogne (Walton 1960-62), and in Limousin (Bans and Bans 1979), as well as elsewhere in the country. Cruck buildings also occur in Northern Ireland (McCourt 1960-62; 1964-65), and Scandinavia (Erixon 1937, 142).

Cruck framing is a very ancient method of building in which a large tree is split in half and the two parts positioned as mirror images opposite one another to form the combined wall and roof supports. In Scotland a pair of crucks cut from the same tree and used to oppose one another is referred to as a "couple" (Walker 1979, 47). A similar terminology appears in Ireland (Evans 1939). At least two cruck pairs are needed and frequently more than that were used.

In its purest form the cruck truss should support a roof in its entirety, carrying the thrust down to a sill-beam at ground level . . . variations exist in which the walls play a partial load-bearing role. These include buildings in which the crucks are seated in the walls above the ground level. (Alcock 1981, 3)

In the later Middle Ages, as population grew in England and the demand for timber increased, the supply of large trees diminished and their cost rose. Eventually, the shortage of large timbers became so critically short that Henry VIII promulgated an edict to stop the construction of cruck frames in favor of box, in order to preserve the timber for naval shipbuilding. The spread of box framing permitted the use of smaller timber than crucks. A consequence of this new emphasis and the innovation of the chimney was the introduction of upper floors, which cruck buildings could not accommodate very well. The box frame dwellings, which already dominated the east and southeast of England, where cruck trusses were virtually unknown, began to spread westward.

The cruck truss and the box frame are two quite different systems of construction. The cruck truss transfers the weight of the entire structure directly to the ground by means of the crucks. Outward thrust is counterbalanced and absorbed by the curve of the cruck. The box frame transfers the weight of the walls, including beams, to the ground by means of its posts. The weight of the roof structure is transferred to the ground by means of a system of rafters, collar beams, girts, king posts or other upper supports, and finally to the house posts. The upper support system works to counteract the outward thrust produced by the roof. An early strategy to assist in countering the roof thrust was to use slanting buttress posts at each house wall and corner post (Chapelot and Fossier 1985, 77). Double rows of holes marking both posts and buttress are a common feature of many archeological sites in northern Europe (Figure 6-8).

One major difference between the cruck truss and the box frame was the roof structure. The cruck truss depended upon a ridgepole for stability. The box frame and rafters, in place of the upper part of the cruck, eliminated the ridge pole and used purlins or horizontally-placed roof boards for stability (Carson 1974, 192). The walls of the cruck frame are not load bearing and thus can be knocked down and rebuilt without damaging the structural framework, which in many houses is effectively hidden behind a later stone or brick shell (Shepp-ard 1966, 25). The box frame required timbers that were squared off so

6-8. Conjectural isometric view of an early dwelling with buttress posts. The plan as revealed by archeological investigation is also shown. Post-holes may be all that remains of early structures (drawing by the author).
Pit Saw Drawing
6-9. Drawing of a pit saw. The man on top is called the sawyer and man below is the pit man (drawing by M. Margaret Geib).

that nogging and cladding could be closely fitted. Hewing of timbers was time consuming and the finished surfaces were irregular.

The early solution was to use the pit saw, which unfortunately was also slow and labor intensive (Figure 6-9). Philip Cox and John Freeland (1969, 16-17) have provided an excellent description of pit sawing in Australia where the saws were copies of European predecessors. Saw pits were:

About five feet deep, four feet six inches wide and eight to twenty feet long. The logs to be sawn were prepared by first having one or more slabs split from their length to produce a flat surface. The parting was done by driving small iron wedges into the smaller end of the log with heavy mauls to start a small split which was then widened by inserting larger wedges into it down the length of the log until the slab fell away. If necessary, the log was rolled over and wedges driven in from the other side. By means of levers and rollers made of saplings, the log was manoeuvered until it lay lengthwise along the pit supported, with the flat surface downwards, on smaller cross timbers. The sawing was done by two men. Using a steel saw five to six feet long, one sawyer stood below the log in the pit and pulled downwards on a vertical tiller. The other bestraddled the log and pulled the saw upwards with a horizontal handle. The latter, the more skilled of the two, was responsible for guiding the saw, for the straightness of the cut and for starting the saw in a notch axed into the end. He was known as the "top-notcher."

This term, top-notch, has, of course, passed into the English language as an idiom to denote the best or most skillful of anything.

Not until the end of the 17th century did things begin to improve with the perfection of the up-and-down saw, and much later the circular saw. Because pit sawing was so laborious, hewn sides were used whenever a regular surface was not needed (Buchanan 1976, 62). The introduction of power sawing was resisted in England "for more than a century by hand sawyers who felt their craft endangered by this form of automation" (Candee 1976, 133). Once accepted, the life of the pit saw was long indeed. Pit saws were used in the Virginia mountains even after the turn of the 20th century (Bealer 1978, 34). Pit sawing did provide two names, which ultimately became common English family names: Pitman and Sawyer. The practice of vernacular building provided a number of other family names in England -Thatcher, Reeder, Slater, Tyler, Carpenter, Joyner, Bricker, Mason, Par-geter, and Dauber. The situation is similar in other languages.

Half timbering is the term widely used, initially in Europe and later in North America, to describe a timber frame structure in which bricks or other earth materials fill the wall space between the wooden framing members. Half timbering was a technique originally used to reduce the amount of timber in a structure because forest resources were dwindling and wood cost rising. The use of bricks as nogging had certain disadvantages. First, early bricks were somewhat porous, which encouraged dampness. Second, the widely disparate rates of expansion and contraction between timber and bricks caused serious cracking that could loosen the nogging. Finally, the bricks were a heavy strain on the timber frame (Brown 1986, 89). The technique became very popular in Great Britain, especially in Hampshire (Brown 2004, 25), in the Low Countries, and in northern Germany, where it was termed fachwerk. As an accepted method of traditional building, fachwerk was brought by emigrating Germans to Missouri, where it still was being used into the 1890s (van Ravenswaay 1977, 20).

The method of timber framing varied from place to place. Even within England three separate approaches can be found. In the east, especially in East Anglia, studs were spaced closely together. In the west, the posts and beams were spaced to produce nearly square, infill panels. In the north, main posts rest on stone foundations. Rows of closely spaced studs and parallel diagonal bracing are prominent, the latter often most prominent on the gable wall (Brown 1986, 46-53).

A variety of materials filled the wall voids between the timber frame members. Initially wattle-and-daub panels were employed, but later these were supplanted by denser materials. This "nogging" was most often of brick whenever it could be afforded, or of mud when brick was too expensive (Figure 6-10). The walls were then covered on

Missouri Mud Cladding

6-10. Layers of mud nogging placed at an angle determined by the cross-brace of the timber frame. The mud was added in rows with each row allowed to dry before the next row was applied. Ruins of a house near Columbia, Missouri (photo by the author, 1980).

the inside by thin wall planks. In cold climates an exterior wooden cladding would also be used for additional insulation. In warmer climates an exterior covering might be applied if "samel brick" had to be used as nogging. Samel bricks were cheap because they were imperfectly fired and disintegrated easily, especially when not protected against the weather (Buchanan 1976, 71 & 73). Thus in North America one finds almost all colonial New England houses to be weather boarded, but in warmer colonial Virginia some structures are half timbered because high-quality bricks had been used. Here, "the primary purpose of nogging was rat proofing instead of insulation" (Buchanan 1976, 71).

The term "box frame" has also been applied to a quite different type of wood construction common in the Appalachian region of the

US (Eller 1979; Williams 1990). In that area, the term refers to a simple house without a structural frame, in which support is provided by vertical planks rather than studs. Because the planks are often rough sawn, small weather strips may be nailed to cover gaps between boards. Box houses became the prevailing house type in Appalachia near the turn of the century when sawmills and the developing timber industry made lumber available at a cheap cost (Eller 1979, 98-9). A closely related house, termed a "strip house" by E. Raymond Evans (1976) was built by African-Americans in the eastern Tennessee Valley during the Depression of the 1930s. Using 2 x 4s as a frame, both horizontal and vertical boards were applied to form the dwellings. These box frame and strip houses may be part of a larger and more diverse set of dwellings that are usually included under the rubric of plank framing.

Plank framing, a variation of post and beam timber framing, became more popular in North America than elsewhere because of the abundant forest resources and the diffusion of saw mills to cut logs into more easily handled planks (Cummings 1979; Candee 1976; Koos and Walters 1986). Some of the same confusion which surrounds French log building methods (see above) also attaches to plank construction (Coffey and Noble 1996). In fact, Thomas Ritchie (1971, 66) sees horizontal plank construction as a variant of the French pièce-sur-pièce log construction technique. He proposes diffusion from Denmark in Viking times, to Quebec during French control, to Ontario and ultimately to other parts of Canada. In a later article, Ritchie (1974) identifies a walling system in which grooved corner posts are eliminated and the horizontal planks rather than vertical planks are nailed at the corners. Both of these, with vertical or horizontal planks, he labels "plank wall." Other researchers have proposed a different and more widely used terminology: plank frame, plank wall, plank-on-edge and plank-on-plank.

The earliest form of plank frame construction in the United States was employed in colonial New England, where vertical planks were rooted into the ground (Carson et al. 1981, 155). Later on, the vertical planks were rabbetted, tenoned or slotted into a wooden sill. In this form the type spread to other parts of the country (Simons 1982, 69; Brinkman and Morgan 1982, 59-60). Like log structures later, and elsewhere, the thick planks were useful in stopping both arrows and low-velocity firearms (Nelson 1969, 21). The relationship of vertical plank construction to timber frame can be seen in the early New England plank houses (Kevlin 1984, 1).

The later but much more widely used plank wall method substituted additional planks for the corner posts. This type, (but unfortunately labeled "plank frame") has been identified in a large number of houses in northeastern Vermont by Jan Leo Lewandoski (1985). In some parts of Vermont, as many as 30-40% of all traditional dwellings were of plank wall construction. A study of traditional dwellings in Independence County, Arkansas revealed that over half of the houses surveyed there were plank wall (Tebbetts 1978). Charles Martin's study (1984) of Hollybush, Kentucky demonstrated widespread use of this construction method in that part of Appalachia. Working in western North Carolina, Michael Ann Williams (1990) found much the same situation, and as a result has suggested that, although not usually recognized as such, plank wall construction is one of the dominant modes of traditional building throughout the entire Upland South of the United States.

Horizontal plank construction is much more rare than vertical, probably because vertical planking eliminates the need for studs and hence is more economical than horizontal (Isham and Brown 1900, 88). The plank-on-edge method of horizontal planking is the least often seen, except in eastern Ontario (Ritchie 1974; Kevlin 1984). Unlike in the rest of New England, plank framing in New Hampshire tended to favor the plank-on-plank method found also in Ontario and as far west as the Great Lakes (Simons 1982, 69). This method requires the greatest amount of lumber, but provides the thickest wall and hence the greatest degree of insulation.

Alternating planks of slightly wider and narrower width to project into the inside of the wall created a key for fixing plaster (Anonymous 1869b, 175). Plaster might even be needed on the exterior "to make the wall windproof (since such a multitude of horizontal joints would otherwise have provided many opportunities for the wind to penetrate the wall) and partly to protect the wooden wall from moisture" which would have caused not only rotting of the wood, but also dimensional changes in the individual boards due to swelling when damp and shrinking when dry (Fitchen 1957, 27).

German-Russian Mennonites used this technique in housebarns in Manitoba, but with 2 x 4s instead of planks (Noble 1992b). Scarcity of wood probably forced them to use narrower boards, but the method (stacking four-inch side upon four-inch side) is identical to the plankon-plank method. No clue exists as to where the Mennonites learned this method, or whether it was improvised locally.

In a volume necessarily limited in size, the enormous amount and complexity of detail involved in timber construction, whether of cruck, box frame or plank building, cannot be adequately discussed. Readers will recognize that many of the sources listed in the references to this volume will be more specific and can remedy the omission here.

Advances at the end of the 18th century and the first half of the 19th century brought about an emphasis on dimension lumber. The perfection of the circular saw produced wood in standardized sizes and in weights much lighter than timber (Ball 1975). Lumber was easier to handle and cheaper than timber. Changes in nail technology saw hand-wrought iron nails replaced first by cut nails and finally by steel wire nails. Hand-wrought nails, made individually by a blacksmith, were so expensive that in colonial America buildings were burned down to salvage them. In 1645 the Virginia House of Burgesses passed legislation prohibiting the burning of houses for this purpose. Yet "in 1691 the Supervisors of nearby Kent County, Delaware ordered the old county courthouse burned in order to get the nails" (Loveday 1983, 4). Kenneth Lindley (1965, 89) suggests that in some impoverished rural communities of Ireland even the custom of removing coffin nails prior to burial arose because of their value as a building material.

Square-cut nails began to be produced in quantity late in the 18th century Made by machine, they were cheaper than hand-wrought nails. At least one researcher estimates that "square cut nails are probably the most numerous artifacts one might expect to find in mid-to-late 19th century Anglo-American-occupied sites in the United States" (Fontana and Greenleaf 1962, 44). Finally, steel nails came into widespread use after 1885 (Edwards and Wells 1993, 2). Cheaply produced nails could be used to fasten light lumber pieces firmly together when needed for greater support. The labor involved in nailing a lumber frame was considerably less than that required to cut mortise and tenon joints and the fastening which treenails required (Kevlin 1984, 1). These innovations, together with the perfection of balloon and platform framing, announced the ultimate end of timber framing. Lumber slowly but steadily replaced timber as the wooden building material.

Modern construction materials are steadily replacing the traditional. The reasons for such replacement are discussed in Chapter 13. One of the most unfortunate aspects of this process is the gradual diminishing of skill levels of craftsmen. Eventually, a rich component of each group's culture will stand in danger of being lost, and an anchor to the past will be removed from the society's consciousness.

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