Ceramic houses

Last updated

Ceramic houses are buildings made of an earth mixture which is high in clay, and fired to become ceramic. The process of building and firing such houses was developed by Iranian architect, Nader Khalili, in the late 1970s. he named it Geltaftan; "Gel", means "clay", and "taftan", means "firing, baking, and weaving clay" in Persian. Khalili's research into creating ceramic houses was strongly based on the idea that permanent, water-resistant, and earthquake-resistant houses could be built with the implementation of the four elements: earth and water to build the forms, and fire and air to finish them. His impassioned work led to a few small scale projects in Iran, including the Javadabad Elementary school, and the Ghaled Mofid restoration project. Aside from Khalili's own documented work, there seems to be little widespread research on ceramic houses.

Nader Khalili was an Iranian-born architect. He is best known for his inventive structures that incorporated a range of atypical building materials to provide shelter in the developing world and emergency contexts.

Contents

History of the Geltaftan method

After having a successful architectural practice in Iran and USA, Nader Khalili's interests turned to rural desert Iran exploring appropriate technology for poor people. While there, Khalili observed how the oldest buildings around were the village kilns, and that their durability came from the fact that the adobe bricks they were made from had been fired in the pottery making process, and therefore hardened. It took years of bureaucratic entanglement, a massive earthquake, and a revolution to get his ideas implemented. In 1978, Khalili with a kiln specialist, rehabilitated twelve houses in the village of Ghaled Mofid in a rural area outside Tehran, Iran. By firing and glazing the homes they became more permanent and safe places for the villagers to live. [1] In 1981, Khalili completed a ten-classroom school of ceramic earth architecture in Javadabad [ disambiguation needed ], Iran.

Appropriate technology is a movement encompassing technological choice and application that is small-scale, decentralized, labor-intensive, energy-efficient, environmentally sound, and locally autonomous. It was originally articulated as intermediate technology by the economist Dr. Ernst Friedrich "Fritz" Schumacher in his work Small is Beautiful. Both Schumacher and many modern-day proponents of appropriate technology also emphasize the technology as people-centered.

Kiln oven that generates high temperatures

A kiln is a thermally insulated chamber, a type of oven, that produces temperatures sufficient to complete some process, such as hardening, drying, or chemical changes. Kilns have been used for millennia to turn objects made from clay into pottery, tiles and bricks. Various industries use rotary kilns for pyroprocessing—to calcinate ores, to calcinate limestone to lime for cement, and to transform many other materials.

Javadabad may refer to:

In 1984 Khalili, who had moved to California by that time, proposed to NASA that ceramic houses be built on the moon. Experiments were conducted by Khalili at McDonnell Douglas Space Systems laboratories to show how harnessing the sun could melt and fuse lunar soil into shapes and forms for building applications. A full-scale model of the proposed colony was intended to be built in the desert outside of Hesperia, CA, where Khalili established his training school: the Cal-Earth Institute. The research received mixed reactions. Khalili was known as "quite a visionary" and thought of as "before his time" by, among others, the mayor of Hesperia, Jim Lindley. [2] Only a few prototypes were built. In 1986 the Geltaftan Foundation was established by Khalili in California for further research into earth architecture. Each of his projects achieved moderate publicity, but Khalili's geltaftan technology has seen little use since the 1980s. This is in part because of the pollution involved in oil firing. The Geltaftan Foundation, and Cal-Earth has since carried on experiments with ceramic housing, but Nader Khalili is most noted today for his work developing Super Adobe: an earth building technique using earth-filled bags as structural elements.

NASA US government agency responsible for civilian space programs, and aeronautical and aerospace research

The National Aeronautics and Space Administration is an independent agency of the United States Federal Government responsible for the civilian space program, as well as aeronautics and aerospace research.

Building and firing

The earth used for building ceramic houses is essentially a type of adobe with a higher clay content and fewer impurities. The earth and water are mixed until the substance has "the consistency of bread dough" [3] The clay/earth mixture is worked into forms, and the blocks dry over a period of one to two weeks. A mortar is made with a "flux" (glass, soda, or colmanite) to help fuse it.

The adobe blocks are laid so that the joints are staggered. There is no mortar in the vertical joints to allow for expansion and contraction during firing. Rammed Earth and Mud Pile can also be fired, but must be fired from both sides because of the thickness of the walls. Building with stiff wet mud, like a potter, allows for thinner walls, and the possibility of incorporating flue systems into the walls. Arches can be formed by stacking non mortared blocks as form work, and removing them after firing.

The firing system used is based on the availability of fuel and local know how. In Iran, village kilns used oil for fuel, so a simple, gravity flow oil burner could be used to fire each room. Flues are created (either integrated into the structural, or made for removal) and openings are closed with un-mortared brick. Joints are covered with a thin layer of mud plaster. The burner is placed at a low opening with room for air circulation, but protected from wind.

During the early stages of firing, 200–900 °C (392–1,652 °F) water vapor escapes through the flues located on the roof. Once the steam escapes, roof flues can be closed and heat will circulate the room before escaping from floor vents. This is when the room is heated to at least 1,000 °C (1,830 °F) and the adobe is baked. After the firing, only the ceiling flues are opened to allow slow cooling over at least 48 hours.

The outside walls are finished with either a mud straw plaster, fired brick, or ceramic tile. When finished with mud straw plaster, a thin layer of clay earth and straw is baked on to the structure at the end phase of firing, and a second layer of the plaster troweled on after cooling. When finished with tiles, they are mortared directly over a waterproofing layer such as tar. [4]

Forms and techniques

The primary shapes of a ceramic building, are squares and rectangles with roofs that are arches, vaults, and domes. This is in order to construct the entire structure of monolithic material (cost effectiveness) and also to achieve the tremor resistance and proven longevity of a shell membrane.

Adobe and clay can be sculpted into built-in forms and structures, such as seats and shelving, and fired with the rest of the house.

Adding oxides and different types of sand and clay can create different finishes. The most important mineral oxide in glazing is silica (which makes glass). Low fired glazes are preferable for houses. Glazing should only be done in some places to allow for a room's skin to "breathe." Glazes have even been made with recycled glass bottles. Salt glazing is another way to make an inexpensive finish. [3]

Benefits

There are many potential benefits to firing an earthen house. Firing makes a clay structure water resistant. Ceramic kilns often outlive the earth constructed buildings they are close to. The materials for this type of building are accessible to those with very basic resources. Fuel for firing is the most expensive investment. The hardened membrane of a ceramic dome improves resistance to earthquakes. The structure of a ceramic house improves passive heat use through thermal mass. Added benefits involving the firing process include the opportunity to produce other ceramic goods for use or income, and, when firing an existing house, pest evacuation will occur naturally.

Examples

Experimental fired earth housing has also been constructed using the principles of an ancient Chinese anagama kiln. In the anagama kiln system, a wood fire is built at the base of a slope, and the gases are drawn by a strong draft up the slope through a tunnel. When a dome is constructed at the end of the tunnel out of clay, the hot gases bake the clay structure to ceramic hardness. [5]

See also

Related Research Articles

Adobe Building material made from earth and organic materials

Adobe is a building material made from earth and organic materials. Adobe is Spanish for mudbrick, but in some English-speaking regions of Spanish heritage, the term is used to refer to any kind of earth construction. Most adobe buildings are similar in appearance to cob and rammed earth buildings. Adobe is among the earliest building materials, and is used throughout the world.

Brick Block or a single unit of a ceramic material used in masonry construction

A brick is building material used to make walls, pavements and other elements in masonry construction. Traditionally, the term brick referred to a unit composed of clay, but it is now used to denote rectangular units made of clay-bearing soil, sand, and lime, or concrete materials. Bricks can be joined together using mortar, adhesives or by interlocking them. Bricks are produced in numerous classes, types, materials, and sizes which vary with region and time period, and are produced in bulk quantities. Two basic categories of bricks are fired and non-fired bricks.

Pottery Craft of making objects from clay

Pottery is the process of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures to give them a hard, durable form. Major types include earthenware, stoneware and porcelain. The place where such wares are made by a potter is also called a pottery. The definition of pottery used by the American Society for Testing and Materials (ASTM), is "all fired ceramic wares that contain clay when formed, except technical, structural, and refractory products." In archaeology, especially of ancient and prehistoric periods, "pottery" often means vessels only, and figures etc. of the same material are called "terracottas". Clay as a part of the materials used is required by some definitions of pottery, but this is dubious.

Clay A finely-grained natural rock or soil containing mainly clay minerals

Clay is a finely-grained natural rock or soil material that combines one or more clay minerals with possible traces of quartz (SiO2), metal oxides (Al2O3, MgO etc.) and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure. Clays are plastic due to particle size and geometry as well as water content, and become hard, brittle and non–plastic upon drying or firing. Depending on the soil's content in which it is found, clay can appear in various colours from white to dull grey or brown to deep orange-red.

Mudbrick Unbaked earth used as building material blocks

A mudbrick or mud-brick is an air-dried brick, made of a mixture of loam, mud, sand and water mixed with a binding material such as rice husks or straw. Though mudbricks are known from 7000 to 6000 BCE, since 4000 BC, bricks have also been fired, to increase their strength and durability.

Mud mixture of water and any combination of soil, silt, and clay

Mud is a liquid or semi-liquid mixture of water and any combination of different kinds of soil. It usually forms after rainfall or near water sources. Ancient mud deposits harden over geological time to form sedimentary rock such as shale or mudstone. When geological deposits of mud are formed in estuaries, the resultant layers are termed bay muds.

Mortar (masonry) workable paste used to bind building blocks

Mortar is a workable paste used to bind building blocks such as stones, bricks, and concrete masonry units, fill and seal the irregular gaps between them, and sometimes add decorative colors or patterns in masonry walls. In its broadest sense mortar includes pitch, asphalt, and soft mud or clay, such as used between mud bricks. Mortar comes from Latin mortarium meaning crushed.

Plaster general term for a broad range of building materials

Plaster is a building material used for the protective or decorative coating of walls and ceilings and for moulding and casting decorative elements. In English "plaster" usually means a material used for the interiors of buildings, while "render" commonly refers to external applications. Another imprecise term used for the material is stucco, which is also often used for plasterwork that is worked in some way to produce relief decoration, rather than flat surfaces.

Tile Manufactured piece of hard-wearing material

A tile is a thin object usually square or rectangular in shape. Tile is a manufactured piece of hard-wearing material such as ceramic, stone, metal, baked clay, or even glass, generally used for covering roofs, floors, walls, or other objects such as tabletops. Alternatively, tile can sometimes refer to similar units made from lightweight materials such as perlite, wood, and mineral wool, typically used for wall and ceiling applications. In another sense, a tile is a construction tile or similar object, such as rectangular counters used in playing games. The word is derived from the French word tuile, which is, in turn, from the Latin word tegula, meaning a roof tile composed of fired clay.

Building material material which is used for construction purposes

Building material is any material which is used for construction purposes. Many naturally occurring substances, such as clay, rocks, sand, and wood, 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 manufacturing 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, insulation, plumbing, and roofing work. They provide the make-up of habitats and structures including homes.

Earthbag construction

Earthbag construction is an inexpensive building method using mostly local soil to create structures which are both strong and can be quickly built.

Anagama kiln

The anagama kiln is an ancient type of pottery kiln brought to Japan from China via Korea in the 5th century. It is a version of the climbing dragon kiln of south China, whose further development was also copied, for example in breaking up the firing space into a series of chambers in the noborigama kiln.

Earth structure A building or other structure made largely from soil.

An earth structure is a building or other structure made largely from soil. Since soil is a widely available material, it has been used in construction since prehistoric times. It may be combined with other materials, compressed and/or baked to add strength. Soil is still an economical material for many applications, and may have low environmental impact both during and after construction.

Architectural terracotta Fired clay construction material

Architectural terracotta refers to a fired mixture of clay and water that can be used in a non-structural, semi-structural, or structural capacity on the exterior or interior of a building. Terracotta is an ancient building material that translates from Latin as "baked earth". It can be unglazed, painted, slip glazed, or glazed. A piece of terracotta is composed of a hollow clay web enclosing a void space or cell. The cell can be installed in compression with mortar or hung with metal anchors. All cells are partially backfilled with mortar.

Superadobe

Superadobe is a form of earthbag construction that was developed by Iranian architect Nader Khalili. The technique uses layered long fabric tubes or bags filled with adobe to form a compression structure. The resulting beehive shaped structures employs corbelled arches, corbelled domes, and vaults to create sturdy single and double-curved shells. It has received growing interest for the past two decades in the natural building and sustainability movements.

Indian vernacular architecture

Indian vernacular architecture the informal, functional architecture of structures, often in rural areas of India, built of local materials and designed to meet the needs of the local people. The builders of these structures are unschooled in formal architectural design and their work reflects the rich diversity of India's climate, locally available building materials, and the intricate variations in local social customs and craftsmanship. It has been estimated that worldwide close to 90% of all building is vernacular, meaning that it is for daily use for ordinary, local people and built by local craftsmen.

Bousillage

Bousillage is a mixture of clay and grass or other fibrous substances used as the infill (chinking) between the timbers of a half-timbered building. This material was commonly used by 18th-century French colonial settlers in the historical New France region of the United States and is similar to the material cob and adobe. In French torchis has the same meaning or the meaning of a loaf of this material.

Wattle and daub building technique using woven wooden supports packed with clay or mud

Wattle and daub is a composite building method used for making walls and buildings, in which a woven lattice of wooden strips called wattle is daubed with a sticky material usually made of some combination of wet soil, clay, sand, animal dung and straw. Wattle and daub has been used for at least 6,000 years and is still an important construction method in many parts of the world. Many historic buildings include wattle and daub construction, and the technique is becoming popular again in more developed areas as a low-impact sustainable building technique.

Ceramic building material, often abbreviated to CBM, is an umbrella term used in archaeology to cover all building materials made from baked clay. It is particularly, but not exclusively, used in relation to Roman building materials.

References

  1. Khalili, Nader. Racing Alone: A Visionary Architect's Quest For Houses made of Earth and Fire. San Francisco: Harper & Row, 1983
  2. Ferrreria, Anton. "Lunar Colony Could Go Up Soon - on Earth" Washington. Reuters.
  3. 1 2 Khalili, Nader. Ceramic Houses and Earth Architecture: How to Build Your Own. San Francisco: Harper & Row, 1986
  4. Khalili, Nader. Ceramic Houses and Earth Architecture: How to Build Your Own. San Francisco: Harper & Row, 1986
  5. Martinez, Alice. "Making a New Life: Trial By Earth and Fire." San Diego Earth Times. December 1995