It’s been weeks since my last post. I could say I was out there doing new research; I could say I had not yet found material to blog about but these are no excuses. Basically, it has been due to sheer laxity. But I’m back on the saddle as this debuts my first post of the year 2016. My content will be about building material.
A year ago, the president of this great Republic of Kenya called upon individuals, construction companies, and the government itself, to come up with innovative ways to coming up with affordable and sustainable housing solutions. This will directly affect the kind of technologies already in existence. So far, I believe the country has headed to this call. Before we go any further, a quick definition and a brief history: Building material is any material which is used for a construction purpose. Many naturally occurring substances, such as clay, sand, wood and rocks, even twigs and leaves have been used to construct buildings.
Apart from naturally occurring materials, many man-made products are in use, some more and some less synthetic. The manufacture of building materials is an established industry in many countries and the use of these materials is typically segmented into specific specialty trades, such as carpentry, plumbing, roofing and insulation work. This reference deals with habitats and structures including homes.
Building materials can be generally categorized into two sources, natural and synthetic. Natural building materials are those that are unprocessed or minimally processed by industry, such as lumber or glass. Synthetic materials are made in industrial settings after much human manipulations, such as plastics and petroleum based paints. Both have their uses.
Mud, stone, and fibrous plants are the most basic building materials, aside from tents made of flexible materials such as cloth or skins. People all over the world have used these three materials together to create homes to suit their local weather conditions. In general stone and/or 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.
A basic example is wattle and daub mostly used as permanent housing in tropical countries in Africa and Asia.
Fabric: The tent used to be the home of choice among nomadic groups the world over. It has been revived as a major construction technique with the development of tensile architecture and synthetic fabrics. In Kenya, the hotel industry has embraced this material in regards to setting up luxury tents in game parks. Personally, I’ve gotten to experience a stay in one of these and to be honest, one does get the ultimate outdoor experience sheltered in this.
Mud and clay: The amount of each material used leads to different styles of buildings. As most of us are familiar with the huts constructed in our rural setting. The deciding factor is usually connected with the quality of the soil being used.
Despite this retrogressive technology, 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. Our African nomadic tribes indeed did have adequate engineering and scientific insight when it came to adopting this tech.
Rock: Rock structures have existed for as long as history and the Flintstone family can recall. It is the longest lasting building material available, and is usually readily available. There are many types of rock throughout 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 without using large amounts of heating resources. As a matter of fact, modern residential and commercial stone buildings have a huger energy density and consequently a huger impact on the ozone in terms of energy consumption emissions in the tropics compared to the industrial set up.
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.
Slate is another stone type, commonly used as roofing material in many 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.
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. Today, it is used in luxury structures themed “makuti” structures. In Europe, thatch roofs on homes were once prevalent but the material fell out of favour as industrialization and improved transport increased the availability of other materials. Today, though, the practice is undergoing a revival. In the Netherlands, for instance, many of new builds too have thatched roofs with special ridge tiles on top.
Wood: A product of trees, and sometimes other fibrous plants, it is 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. 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.
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.
Wood had the challenge of building storied houses and during the post industrial revolution, the race was to reach for the sky. Thus the birth of skyscrapers in cities like Chicago and New York. We have already mentioned the huge impact concrete housing has had on the environment energywise. But wood is making a huge innovative comeback! Architects and structural engineers have designed ways to stack timber together in layers to achieve similar compressive, tensile and flexural strengths to build skyscrapers of wood! Follow this link for more intel http://www.ted.com/talks/michael_green_why_we_should_build_wooden_skyscrapers?language=en
Brick and Block: It 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 widely used 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.
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.
Concrete has been the predominant building material in this modern age due to its longevity, formability, and ease of transport but has the greatest impact on building economies and overall carbon footprint in building design (I will not tire to repeat this again and again). But few innovative Kenyans have found methods to reduce the use of concrete mixtures to achieve similar strengths as concrete while reducing the quantity of material used to make the blocks and designing them to easily interlock to form the structures. The consequential impact is reduced building costs by 40% and reduced carbon footprint of over 25%!
Metal: 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. Corrosion is metal’s prime enemy when it comes to longevity. Metal also has the greatest impact on building economies and overall carbon footprint in building design (what did I say-won’t tire!).
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”.
The world has realized how bad of a state the planet is in due to the continued exploitation of modern technologies for construction. Sustainability has been the main call in doing construction. Today, after the Paris COP 21 summit and the president’s call to come up with various building technologies that can bring up affordable and sustainable housing, several new materials have been embraced towards achieving this, locally and globally. This is the section on sustainable building technologies: I dub them, the New Age technologies.
Compressed soil blocks are different from adobes in that they are not fully saturated with water, are denser than adobes, & significantly more uniform. Because of their uniformity, these blocks need less mortar, & can be dry-stacked. Uniformity also speeds up the laying process & results in straighter walls. This has been aggressively advertised as the Makiga interlocking bricks.
While making compressed soil blocks is labor intensive, they can significantly reduce the costs involved in building a house, outbuildings, fences, garden walls, etc. If soil consisting of clay, caliche & silt is available at the building site, admixtures can be omitted, thus the only cost involved in producing compressed soil blocks is the block press and the time invested by the builder.
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. A company in Kenya, Strauss Energy has found a very innovative way to incorporate solar panels into the ceramic roofing tiles. The resulting outcome is just revolutionary!
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.
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 thinner metals finished in cement.
Bamboo can be utilized as a building material as for scaffolding, bridges and houses. Bamboo, like true wood, is a natural composite material with a high strength-to-weight ratio useful for structures. Bamboo has a higher compressive strength than wood, brick or concrete and a tensile strength that rivals steel. Bamboo solutions are a highly sustainable, cost-effective and beautiful construction material for homes. It can be used throughout the entire structure (inside and out) and if preventative measures are utilized, can last for many years. It is no wonder that Asian and Central and South American cultures have grown to rely upon this hearty grass for so many facets of their lives.
Modern building is a multibillion dollar industry, and the production and harvesting of raw materials for building purposes is on a world wide scale. Often being a primary governmental and trade keypoint between nations. Environmental concerns are also becoming a major world topic concerning the availability and sustainability of certain materials, and the extraction of such large quantities needed for the human habitat.
Today, our Kenyan government has embarked on providing housing solutions to our police service men and women. A budget of KES 18-20 Billion has been set aside for the construction of some 20,000 units in a combination of bedsitters, 1,2, and 3 bedroom houses for them . This means a unit could cost averagely KES 900,000. This is quite impressive in terms cost reduction to construct affordable housing. In my opinion and through my continued research, I believe the related costs could have gone lower and constructed 10 times as many units with the same kind of budget.
But hey, I’m no policy maker…I’m just a blogger trying to get this information to my fellow citizens of the world in an effort to trying to restore this beloved planet of ours to the days of the Garden of Eden.
“On This Day in Engineering History: 30/8/1983 U.S. Air Force Lieutenant Colonel Guion S. Bluford becomes the first African American to travel into space when the space shuttle Challenger lifts off on its third mission. After combat service, he became a flight instructor and in the 1970s went on to receive a master’s degree and doctorate in aerospace engineering from the Air Force Institute of Technology. In 1979, he was accepted into the U.S. astronaut program. He made his first flight in 1983 as a mission specialist on the eighth shuttle mission. After returning from NASA, he became vice president and general manager of an engineering company in Ohio.”