Information about Building Material

For other kinds of building materials, see Hardware, Biology, Star formation.

Building material is any material which is used for a construction purpose. Just about every type of available material has been used at one time or another for creating various human and animal homes, structures, and technologies. This reference deals with habitats and structures including homes.

Living spaces and their related structures have been created using myriad materials, from mud to metal, and from plastic to grass. Today the production and assembly of various building materials is a multibillion dollar industry, and environmental concern has recently surfaced about the effects of such a massive resource extraction on a global scale.

Natural materials

Mud, rocks, and small plants are used as the most basic building materials, aside from tents made of flexible materials such as cloth or leather. People all over the world have used these three materials together to create homes to suit their local weather conditions. In general stone and brush are used as basic structural components in these buildings, while mud is used to fill in the space between acting as a type of concrete and insulation.

Some examples are the wattle and daub mostly used as permanent housing in tropical countries or as summer structures by ancient northern peoples.

Mud and clay

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 then 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.

Rock

Rock structures have exisited for as long as history can recall. It is the longest lasting building material available, and is usually readily available. There are many types of rock through out the world all with differing attributes that make them better or worse for particular uses. Rock is a very dense material so it gives a lot of protection too, its main draw-back as a material is its weight and awkwardness. Its energy density is also considered a big draw-back, as stone is hard to keep warm with out using large amounts of heating resources.

Dry-stone walls have been built for as long as humans have put one stone on top of another. Eventually different forms of mortar were used to hold the stones together, cement being the most commonplace now.

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 (see Dartmoor longhouse) 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 civilisations built entirely with stone such as the Pyramids in Egypt, the Aztec pyramids and the remains of the Inca civilisation.

Thatch

Thatch is one of the oldest of building materials known; grass is a good insulator and easily harvested. Many African tribes have lived in homes made completely of grasses year round. In Europe, thatch roofs on homes were once prevalent but the material fell out of favour as industrialisation and improved transport improved the availability of other materials. Today, though, the practice is undergoing a revival. In Holland, for instance, two-thirds of new builds have thatched roofs.

Brush

Brush structures are built entirely from plant parts and are generally found in tropical areas, such as rainforests, where very large leaves can be used in the building. Native Americans often built brush structures for resting and living in, too. These are built mostly with branches, twigs and leaves, and bark, similar to a beaver's lodge. These were variously named wikiups, lean-tos, and so forth.

Ice

Ice was used by the Inuit for igloos, but has also been used for ice hotels as a tourist attraction in northern areas that might not otherwise see many winter tourists.

Wood

Wood is a product of trees, and sometimes other fiberous 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.

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 in to place.

In earlier times, and in some parts of the world, many country homes or communities had a personal wood-lot from which the family or community would grow and harvest trees to build with. These lots would be tended to like a garden.

With the invention of mechanizing saws came the mass production of dimensional lumber. This made buildings quicker to put up and more uniform. Thus the modern western style home was made.

Brick and Block

A brick is a block made of kiln-fired material, usually clay or shale, but also may be of lower quality mud, etc. Clay bricks are formed in a moulding (the soft mud method), or in commercial manufacture more frequently by extruding clay through a die and then wire-cutting them to the proper size (the stiff mud process).

Bricks were very popular as a building material in the 1700, 1800 and 1900s. This was probably due to the fact that it was much more flame retardant than wood in the ever crowding cities, and fairly cheap to produce.

Another type of block replaced clay bricks in the late 20th century. It was the Cinder block. Made mostly with concrete.

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.

For a concrete construction of any size, as concrete has a rather low tensile strength, it is generally strengthened using steel rods or bars (known as rebars). This strengthened concrete is then referred to as reinforced concrete. In order to minimise any air bubbles, that would weaken the structure, a vibrator is used to eliminate any air that has been entrained when the liquid concrete mix is poured around the ironwork. Concrete has been the predominant building material in this modern age.

Metal

Metal is used as structural framework for larger buildings such as skyscrapers, or as an external surface covering. There are many types of metals used for building. Steel is a metal alloy whose major component is iron, and is the usual choice for metal structural building materials. It is strong, flexible, and if refined well and/or treated lasts a long time.

The lower density and better corrosion resistance of aluminium alloys and tin sometimes overcome their greater cost. Brass was more common in the past, but is usually restricted to specific uses or specialty items today. Other metals used include titanium, chrome, gold, silver. These are used as decoration because they are too soft to provide any structural support. Corrosion is metal's prime enemy when it comes to longevity.

Metal figures quite prominently in prefabricated structures such as the Quonset hut, and can be seen used in most cosmopolitan cities. It requires a great deal of human labor to produce metal, especially in the large amounts needed for the building industries.

Glass

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, and is very brittle.

Modern glass "curtain walls" can be used to cover the entire facade of a building. Glass can also be used to span over a wide roof structure in a "space frame".

Titanium and chrome are very hard metals, though chrome is very brittle, too. titanium can be used for structural purposes, though it is quite expensive. Chrome, gold and silver are also expensive and can only used for decorational purposes, being gold and silver quite soft.

Some major items used in building are derived from Hot Rolled Coils, Cold Rolled Coils, Galvanized COils and ther on.

Ceramics

Ceramics are such things as tiles, fixtures, etc. Ceramics are mostly used as fixtures or coverings in buildings. Ceramic floors, walls, counter-tops, even ceilings. Many countries use ceramic roofing tiles to cover many buildings.

Ceramics used to be just a specialized form of clay-pottery firing in kilns, but it has evolved into more technical areas.

Plastic

The term plastics covers a range of synthetic or semi-synthetic organic condensation or polymerization products that can be molded or extruded into objects or films or fibers. Their name is derived from the fact that in their semi-liquid state they are malleable, or have the property of plasticity. Plastics vary immensely in heat tolerance, hardness, and resiliency. Combined with this adaptability, the general uniformity of composition and lightness of plastics ensures their use in almost all industrial applications today.

Fabric

The tent used to be the home of choice among nomadic groups. Two well known types include the conical teepee and the circular yurt. It has been revived as a major construction technique with the development of tensile architecture. Modern buildings can be made of flexible material such as fabric membranes, and supported by a system of steel cables or internal air pressure.

Foam

More recently synthetic polystyrene or polyurethane foam has been used on a limited scale. It is light weight, easily shaped and an excellent insulator. It is usually used as part of a structural insulated panel where the foam is sandwiched between wood or cement.

Wood cement composites

Wood-Cement Compatibility

Cement bonded composites are an important class of building materials. These products are made of hydrated cement paste that binds wood or alike particles or fibres to make pre-cast building components. Wood and natural fibres are composed of various soluble organic compounds like carbohydrates, glycosides and phenolics. These compounds are known to retard cement setting. Therefore, before using a wood in making cement boned composites, its compatibility with cement is assessed.

Wood-cement compatibility is the ratio of a parameter related to the value of property of a wood-cement composite to that of a neat cement paste. The compatibility is often expressed as a percentage value. To determine wood-cement compatibility, methods based on different properties are used, such as, hydration characteristics, strength, interfacial bond and morphology. Various methods are used by researchers such as the measurement of hydration characteristics of a cement-aggregate mix [1-3]; the comparison of the mechanical properties of cement-aggregate mixes [4-5] and the visual assessment of microstructural properties of the wood-cement mixes [6]. It has been found that the hydration test by measuring the change in hydration temperature with time is the most convenient method. Recently, Karade et al. [7] have reviewed these methods of compatibility assessment and suggested a method based on the ‘maturity concept’ i.e. taking in consideration both time and temperature of cement hydration reaction.

References
1. 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.
2. Weatherwax, R.C. and Tarkow, H. (1964) Effect of wood on setting of Portland cement. For. Prod. J. 14(12), 567-570.
3. 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.
4. 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.
5. 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.
6. Ahn, W.Y. and Moslemi, A.A. (1980) SEM examination of wood-Portland cement bonds. Wood Sci .13(2), 77-82.
7. Karade SR, Irle M, Maher K (2003) Assessment of wood-cement compatibility: A new approach. Holzforschung, 57: 672-680.

Virtual materials

Main article: Materiality (architecture)

Certain materials like photographs, images, text may be considered virtual. While, they usually exist on a substrate of natural material themselves, they acquire a different quality of salience to natural materials through the process of representation.

See also

• Materiality (architecture)
• List of building materials
• Phase I Environmental Site Assessment