The major elements of a building include the following:

 

1. The foundation, which supports the building and provides stability

 

2. The structure, which supports all the imposed loads and transmits them to the foundation

 

3. The exterior walls, which may or may not be part of the primary supporting structure

 

4. The interior partitions, which also may or may not be part of the primary structure

 

5. The environmental-control systems, including ventilating, fire-pits, and lighting

 

6. The vertical transportation systems, such as dumbwaiters, service shafts, ramps and stairways

 

7. The power, water supply, and waste disposal systems

 

Foundations

 

The structural design of a building depends greatly on the nature of the soil and underlying geologic conditions and modification by man of either of these factors.

 

Ground Conditions

 

If a building is to be constructed in an area that has a history of earthquake activity, the earth must be investigated to a considerable depth. Faults in the crust of the earth beneath the soil must obviously be avoided. Some soils may liquefy when subjected to the shock waves of a quake and become like quicksand. In such cases, either construction must be avoided altogether or the foundation must be made deep enough to reach solid material below the potentially unstable soil. Certain clay soils have been found to expand 23 cm (9 in) or more if subjected to long cycles of drying or wetting, thus producing powerful forces that can shear foundations and lift lightweight buildings. Some soils with high organic content may, over time, compress under the building load to a fraction of their original volume, causing the structure to settle. Other soils tend to slide under loads.

 

Soils that have been modified in some way often perform differently, especially when other soil has been added to or mixed with existing soil, or when the soil has been made wetter or drier than normal, or when cement or chemicals such as lime have been added. Sometimes the soil under a proposed building varies so greatly over the entire site that a building simply cannot be constructed safely or economically.

 

Soil and geologic analyses are necessary, therefore, to determine whether a proposed building can be supported adequately and what would be the most effective and economical method of support.

 

If there is sound bedrock a short distance below the surface of the construction site, the area over which the building loads are distributed can be quite small because of the strength of the rock. As progressively weaker rock and soils are encountered, however, the area over which the loads are distributed must be increased.

 

The most economical foundation is the reinforced-concrete spread footing, which is used for buildings in areas where the subsurface conditions present no unusual difficulties. The foundation consists of concrete slabs located under each structural column and a continuous slab under load-bearing walls.

 

Mat foundations are typically used when the building loads are so extensive and the soil so weak that individual footings would cover more than half the building area. A mat is a flat concrete slab, heavily reinforced with steel, which carries the downward loads of the individual columns or walls. The mat load per unit area that is transmitted to the underlying soil is small in magnitude and is distributed over the entire area. For large mats supporting heavy buildings, the loads are distributed more evenly by using supplementary foundations and cross walls, which stiffen the mat.

 

Piles are used primarily in areas where near-surface soil conditions are poor. They are made of timber, concrete, or steel and are located in clusters. The piles are driven down to strong soil or rock at a predetermined depth, and each cluster is then covered by a cap of reinforced concrete. A pile may support its load either at the lower end or by skin friction along its entire length. The number of piles in each cluster is determined by the structural load and the average load-carrying capacity of each pile in the cluster. A timber pile is simply the trunk of a tree stripped of its branches and is thus limited in height. A concrete pile, on the other hand, may be of any reasonable length and may extend below groundwater level as well. For extremely heavy or tall buildings, steel piles, known as H-piles because of their shape, are used. H-piles are driven through to bedrock, often as far as 30 m (100 ft) below the surface. H-piles can be driven to great depths more easily than piles made of wood or concrete; although they are more expensive, the cost is usually justified for large buildings, which represent a substantial financial investment.

 

Caisson foundations are used when soil of adequate bearing strength is found below surface layers of weak materials such as fill or peat. A caisson foundation consists of concrete columns constructed in cylindrical shafts excavated under the proposed structural column locations. The caisson foundations carry the building loads at their lower ends, which are often bell-shaped.

 

Brick and Tile

 

One of Gor's oldest building materials is the brick. It is a small, rectangular block, usually made of clay that has been burned in a kiln for strength, hardness, and heat resistance. The most common dimensions for a brick are 2 1/4 × 3 3/4 × 8 inches (5.5 × 9.5 × 20 centimeters). Bricks are manufactured almost everywhere--because they are extensively used, because clay is found throughout the world, and because brick-making technology is relatively simple.

 

Tile is made of oven-baked clay. Facing tile is the most familiar. It is usually flat, square or rectangular, glazed, and decorative as well as functional. It is most commonly seen affixed with mortar to richly decorated walls and floors. Structural clay tile, also called terra-cotta, is a larger building unit containing many hollow spaces. It is used mostly to back up brick facing or plastered walls. Other forms include unglazed, or common, tile for roofing and drainpipes and sewer pipes that have been vitrified, or fired to obtain a glasslike surface.

 

Kinds of Brick

 

Kiln-burned brick, the most common type, is made of clay and sand. It may or may not have holes through the center. Facing brick, a kiln-burned type with a smooth surface and attractive appearance, is intended for the most visible parts of buildings. Common brick, less attractive and less expensive, is used for side-walls. Brick veneer, a kind of paneling made of shallow bricks joined by mortar, is fastened to interior walls for decorative purposes.

There are many types of bricks for fancy work. Tapestry brick has a design pressed onto it in the mold in which it is formed. Facing brick may have one or more of its surfaces glazed by use of gases or ceramic materials. Bricks in unusual shapes for making arches and the like are formed in special molds.

 

Flooring brick, used in such places as Central Cylinders, where the floors receive heavy use, is very hard and dense. Firebrick, used in lining things such as fire-pits, is made of a special clay. Refractory brick, which withstands very high temperatures, is used in specialized Builder furnaces. It contains zirconia, magnesia, chromite, or other minerals.

 

Adobe brick, made of clay mixed with straw or chopped reeds and dried in the sun, is used in hot, dry places such as Tor. Walls of adobe brick must stand on waterproof foundations and be protected from rain by overhanging roofs of more durable material or they will melt. This is why most Torian buildings are usually coated with an outer layer of sun dried clay, usually painted white in order to reflect back the suns rays, while all the time protecting the brick which lies within.

 

Because brick-making is practiced Gor-wide in so many cities, current manufacturing technology ranges from traditional hand methods, virtually unchanged from the millennia ago, to modern mass-production techniques that produce thousands of bricks each week. Regardless of the technology employed, however, the basics of brick-making are the same: to obtain and prepare clay, mix it with other substances as needed, form and dry the new bricks, burn them in a kiln, and cool them off.

 

The strength of brickwork depends as much on the manner in which the bricks are laid as it does on their quality. They must interlock to remain bonded together. To make interlocking easier, bricks are usually made about twice as long as they are wide. Bricklayers usually dampen bricks before laying them.

 

A brick laid parallel to the face of a wall is called a stretcher. A brick laid crosswise, or perpendicular to the wall face, is called a header. Any horizontal row of bricks is called a course. Bonding is an arrangement of stretchers and headers, with the latter linking the front and back of a wall. The bricks in each course overlap those below, so that joints do not line up vertically. There are several types of bonding. Each is used to create a different pattern. The lines in a pattern may be emphasized by using colored bricks.

 

The joints, or spaces between the bricks, are filled with mortar to hold them together. Thus, the mortar and joints are important to the durability of the work. Joints range in thickness from thin "buttered" joints to some that are 1 inch (2.5 centimeters) wide. The mortar in joints may be tooled into various shapes, raked out, or cut flush. This, plus the fact that the mortared joints usually make up about 15 percent of a wall, make them important for appearance as well as for durability. A brick broken in half is called a bat. When used to fill out a course at a corner, it is called a closer. Bricks are sometimes set vertically, as in porch posts. The stretchers are then called soldiers; the headers, rowlocks.

 

Tile

 

There are more kinds of tile than of brick. One, called terra-cotta, is a kiln-fired clay building unit in the form of a block pierced with many rectangular holes. It is often used to make the core of a wall that is then finished with a covering of brick, stone, stucco, or plaster. Because its surface is easy to mold or texture, terra-cotta is often used decoratively on building exteriors. Unglazed terra-cotta comes in earth colors, while glazed types can be colored in many ways and given a shiny or matte (dull) finish.

 

Glazed or unglazed clay piping, available in numerous shapes and sizes, is also a kind of tile. These pipes are made with varying strengths, water permeability, and other characteristics to meet specific needs. Roofing tile, used widely in Tor, comes in several different shapes. Both unglazed and glazed types are common, the latter in many colors. Flooring and wall tile, or facing tile, comes unglazed with a single color throughout, or glazed with a design fused to the surface. Such tile is valued for its waterproof, readily maintainable surface, and often, too, for its beauty. 

 

Special tiles, used ornamentally both indoors and out, include faience, majolica, and delft. Faience tile, which was named after Master Builder Faenza, who created it hundreds of years ago, has striking opaque glazes. Majolica tile, with bright decorations fired onto its surface, is named for the Ko-ro-ban Builder Majorca, who first made it around the same era of Faenza. Delft, named after the Turian Builder, has celestial-style decorations, usually in blue or white.

 

Other tiles include quarry and paver types used for flooring. Quarry tile withstands heavy outdoor traffic and comes in only a few colors. Pavers, on the other hand, are for lighter wear and are available in a wider range of hues.

 

Floor and wall tiles are made by the dust-press or plastic method. In the dust-press process, the clay mixture is formed in steel dies under great pressure, removed, and fired to very high temperatures. This produces quite precise tile shapes and sizes. In the plastic process, the mixture is either hand-molded or extruded (squeezed out) from a die, and then fired. This results in a somewhat rougher-looking product. Surface-glazed tiles made either way have their decoration added and fused to the tile in a second firing.

 

*A special thanks to the creators of the LBoG and to Ubar Luther for much of the information provided on this page.