MATERIALS
Vernacular architecture is a term used to categorize methods of construction which use locally available resources and traditions to address local needs. Vernacular architecture tends to evolve over time to reflect the environmental, cultural and historical context in which it exists. It has often been dismissed as crude and unrefined, but also has proponents who highlight its importance in current design. It can be contrasted against polite architecture which is characterized by stylistic elements of design intentionally incorporated for aesthetic purposes which go beyond a building's functional requirements. The building knowledge in vernacular architecture is often transported by local traditions and is thus based largely - but not only - upon knowledge achieved by trial and error and handed down through the generations, in contrast to the geometrical and physical calculations that underlie architecture planned by architects. This of course does not prevent architects from using vernacular architecture in their designs or from being firmly based in the vernacular architecture of their regions.
Types of Vernacular Material
Timber/wood
Wood is a product of trees, and sometimes other fibrous plants, used for construction purposes when cut or pressed into lumber and timber, such as boards, planks and similar materials. It is a generic building material and is used in building just about any type of structure in most climates. Wood can be very flexible under loads, keeping strength while bending, and is incredibly strong when compressed vertically. There are many differing qualities to the different types of wood, even among same tree species. This means specific species are better for various uses than others. And growing conditions are important for deciding quality.
Timber/wood had been used for centuries as a type of building materials. Some of which are bridge and huts that were build at the very first era of construction where materials like concrete and steel are unknown materials yet. Historically, wood for building large structures was used in its unprocessed form as logs. The trees were just cut to the needed length, sometimes stripped of bark, and then notched or lashed into place. Timber is also being categorized as superior building material on environment criteria. In other words it is said to be the most environment friendly building material.
The essential elements of timber frame building—joined timbers, clay walls and thatch roof were in place in Europe and Asia by the 9th century. It remained the common mode of house construction in northern cultures until the 19th century. Craftsmanship was, and is, an important value in timber frame building. The oldest timber frame structures (for example, the timber framed stave churches of Scandinavia) show both craftsmanship and a strong grasp of the technical aspects of structural design, as do such structures in Japan.
Timber framing typically uses a "bent." A bent is a structural support, like a truss, consisting of two posts, a tie beam and two rafters. These are connected into a framework through joinery. To practice the craft, one must understand the basic structural aspects of the bent. This, along with a knowledge of joinery, are the basis of timber frame building.
The granite-strewn uplands of Dartmoor National Park, United Kingdom, for example, provided ample resources for early settlers. Circular huts were constructed from loose granite rocks throughout the Neolithic and early Bronze Age, and the remains of an estimated 5,000 can still be seen today. Granite continued to be used throughout the Medieval period and into modern times. Slate is another stone type, commonly used as roofing material in the United Kingdom and other parts of the world where it is found. Mostly stone buildings can be seen in most major cities, some civilizations built entirely with stone such as the Pyramids in Egypt, the Aztec pyramids and the remains of the Inca civilization.
Mud
The amount of each material used leads to different styles of buildings. The deciding factor is usually connected with the quality of the soil being used. Larger amounts of clay usually mean using the cob/adobe style, while low clay soil is usually associated with sod building. The other main ingredients include more or less sand/gravel and straw/grasses. Rammed earth is both an old and newer take on creating walls, once made by compacting clay soils between planks by hand, now forms and mechanical pneumatic compressors are used.
Soil and especially clay is good thermal mass; it is very good at keeping temperatures at a constant level. Homes built with earth tend to be naturally cool in the summer heat and warm in cold weather. Clay holds heat or cold, releasing it over a period of time like stone. Earthen walls change temperature slowly, so artificially raising or lowering the temperature can use more resources than in say a wood built house, but the heat/coolness stays longer.Peoples building with mostly dirt and clay, such as cob, sod, and adobe, resulted in homes that have been built for centuries in western and northern Europe as well as the rest of the world, and continue to be built, though on a smaller scale. Some of these buildings have remained habitable for hundreds of years.
Straw/Reed
Straw is what’s left over when grains, such as wheat, rice, barley, oats, and rye, are harvested. About 140 million tons (128 million tonnes) of straw are produced each year in North America.
Straw is appealing as a building material for several reasons. First, in areas of grain production, straw is inexpensive. Second, the quality of lumber is dropping, prices are unpredictable, and some suggest future supplies may be limited. Third, because straw is a secondary waste material from grain production, its embodied energy should be fairly low. Fourth, in many areas straw is still burned in fields, producing significant air pollution. In California more than 1 million tons of rice straw were burned each fall in the early 1990s, generating an estimated 56,000 tons (51,000 tonnes) of carbon monoxide annually—twice that produced from all of the state’s power plants! Regulations to ban straw burning are being implemented in many parts of the country, both to reduce air pollution and to reduce the risk of accidents that can occur when shifting winds blow smoke over highways.
In some areas most straw is tilled back into the soil. While straw provides few nutrients to the soil, it does add organic matter and helps aerate the soil. Rollie Sears, a wheat specialist at the Kansas State Agronomy Department, is concerned that the state’s agricultural soils would suffer if all of the straw was harvested. “Taking the straw away would eventually have some pretty significant consequences,” he said. Sears believes that, with careful management, intermittent harvesting of the straw could be done without harm.
Types of Material
Steels
Steel is utilized in a wide range of buildings and constructions since steel is an extremely versatile and reliable building material. Until the middle of the 19th century, steel could not be mass produced and creating entire buildings from steel was therefore more or less impossible. Today, steel is one of the most reasonably priced building materials and appreciated world wide. When it comes to construction work, steel is by far the most frequently used metal building material. In theory it would of course be possible to construct a metal building from other metals with similar properties, e.g. titan, but in real life this is not a practical solution due to economical and practical factors.
Steel can either be used to create an entire building, or be combined with other building materials. Everything from weight carrying parts to roofs, walls and covering can be made from steel. Creating an entire building from steel will make it possible to rapidly erect an affordable building without having to give up factors such as durability, safety and design. Earlier, steel buildings were often quite unattractive and barren, but today you can get stylish steel buildings that look great and create a comfortable atmosphere. It is also common to combine steel with other types of building materials, e.g. concrete. In skyscrapers, steel is usually used to create a durable frame system, while concrete is utilized for walls, floors and roofing.
Concrete
Concrete is a composite building material made from the combination of aggregate (composite) and a binder such as cement. The most common form of concrete is Portland cement concrete, which consists of mineral aggregate (generally gravel and sand), portland cement and water. After mixing, the cement hydrates and eventually hardens into a stone-like material. When used in the generic sense, this is the material referred to by the term concrete.
Glass
Glassmaking is considered an art form as well as an industrial process or material.Clear windows have been used since the invention of glass to cover small openings in a building. They provided humans with the ability to both let light into rooms while at the same time keeping inclement weather outside. Glass is generally made from mixtures of sand and silicates, in a very hot fire stove called a kiln and is very brittle. Very often additives are added to the mixture when making to produce glass with shades of colors or various characteristics (such as bullet proof glass, or light emittance).
The use of glass in architectural buildings has become very popular in the modern culture. Glass "curtain structure in a "space frame". These uses though require some sort of frame to hold sections of glass together, as glass by its self is too brittle and would require an overly large kiln to be used to span such large areas by itself.
Sandermann, W. and Kohler, R. (1964) Studies on mineral-bonded wood materials. IV. A short test of the aptitudes of woods for cement-bonded materials. Holzforschung 18, 53:59.
Weatherwax, R.C. and Tarkow, H. (1964) Effect of wood on setting of Portland cement. For. Prod. J. 14(12), 567-570.Hachmi, M., Moslemi, A.A. and Campbell, A.G. (1990) A new technique to classify the compatibility of wood with cement. Wood Sci. Technol. 24(4), 345-354.
Hong, Z. and Lee, A.W.C. (1986) Compressive strength of cylindrical samples as an indicator of wood- cement compatibility. For. Prod. J. 36(11/12), 87-90.
Demirbas, A. and Aslan, A. (1998) Effects of ground hazelnut shell, wood and tea waste on the mechanical properties of cement. Cement Concrete Res. 28(8), 1101-1104.
Ahn, W.Y. and Moslemi, A.A. (1980) SEM examination of wood-Portland cement bonds. Wood Sci .13(2), 77-82.
Karade SR, Irle M, Maher K (2003) Assessment of wood-cement compatibility: A new approach. Holzforschung, 57: 672-680
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