Stone
Rocks, pebbles and gravel are all made of ston e. Stone is a natural material which is dug from quarries in the ground.
Pebbles are found at the coast. They are pieces of stone rounded and smoothed by the action of the sea. It can be interesting to collect different coloured pebbles and to sort them. Some pebbles you might find could be flint, granite or sandstone.
The stone used for buildings is a heavy material. It is mostly used where there is a supply nearby. There are exceptions to this. Some of the stone is used in building. Stonehenge in England was brought to the site from south-west Wales, nearly 350 km away. Stone is a hard-wearing material.
Stone can be used to decorate houses. Some houses have pebble-dashed walls, where the house is coated with a thin layer or cement, then tiny pebbles are thrown into the effect. Flint is a particular kind of stone. It is sometimes used for decoration. Flint is very hard.
Most of the stone quarried is used as basis for road building. Stone provides roads with a hard, solid base or foundation. In road-surfacing, stone chips are mixed with tar to produce a hard-wearing surface.
Gravel is made up of small pieces of stone. It is used in making concrete and for surfacing paths and driveways around houses. Gravel is obtained from the ground. Where it is removed, it leaves huge holes in the ground. These usually are filled with water and become small lakes.
Wood
Wood is a natural material obtained from trees. The trees are cut down, dried and sawn into manageable pieces called planks.
Before wood can be used it has to be dried. The process of drying wood is called seasoning. Wood is usually seasoned quickly in special ovens called kilns. It can be dried very slowly in the open air. Wood is a very useful material because:
• it can be very strong;
• it can be bent easily;
• it can be of light weight;
• it can be shaped easily;
• it can be joined easily.
Wood is used as a building material because it is easy to be cut and shaped. It can be joined using nails, screws or glue. If it is looked after, it will last for a long time. Wooden window frames and door frames can be painted. This helps to stop the wood from rotting.
Clay
Clay is a natural material which comes out of the ground. It is made up of pieces of rock so tiny that they stick together to make a soft substance. When soft clay is dried or baked inside an oven or a kiln it becomes very hard. This process is called firing.
Bricks for building are made by firing clay at very high temperatures. This makes it very hard and ideal for walls. Walls are usually made by setting the bricks into a cement mixture called mortar. In Mexico, clay bricks are shaped, then dried in the sun. The bricks are stuck together with liquid clay to make walls. Walls built like this are called adobe walls.
Roof tiles and some water pipes are also made by firing clay at high temperatures. In some parts of Britain, clay is used as a building material for cob walls. Cob walls are a mixture of clay, gravel, sand and straw, built up layer by layer. Houses built with walls of this material need to be made waterproof by coating with lime wash. Clay is a good insulator. It is very good at keeping temperatures at a constant level like stone.
Plastics
Plastics are widely used for many different purposes. It is used for building because it will not rust or decay. This means plastics-coated window frames and doors are easier to look after than wooden ones, and they do not rot. They do not have to be painted.
There are many kinds of plastics, including polythene and nylon. They are all made of chemicals which come from oil. Most plastics are not coloured at first, so dye is added to colour them. Some plastics are rigid and will snap if you try to bend them. Others are flexible and bend easily. They can be quite soft. Some plastics can only be shaped once. They are called thermosets. Other plastics can change shape when heated. They are called thermoplastics.
Glass
Glass is a manufactured material. It is important in everyone’s daily life. Glass is made by heating sand together with substances called soda and lime in a furnace until they melt. When it cools, the mixture will be glass.
Nobody really knows who first discovered how to make glass. It is thought that around 5,000 years ago, the Egyptians were already using it to make jugs and vases. The Romans were the first to use glass window panes. These have since been found during archaeological excavations at places such as Pompeii.
Glass is used for windows because it can be made transparent and it lets the light through. You саn see clearly through transparent glass. Glass for windows is made in very large sheets. It is then cut to size.
Many buildings, including churches sometimes have colourful stained glass windows. Many stained glass windows are very old. They may be pictures showing stories, or they may be made into bright patterns.
The windows of patio doors must be toughened by safety glass in case people walk into them. Safety glass is made so that it will not shatter and splinter if broken. It is very strong.
Patterned or frosted glass is often used for bathroom windows. This type of glass lets light in, but it is difficult to see through. It is translucent.
Metals
Sixty of the hundred or so elements in the periodic table of the elements, which make up all known matter, are classified as metals. The remaining elements which include sulphur, chlorine, phosphorus or nitrogen, are simply called non-metals.
The best known metallic elements are iron, copper, zinc, tin, lead, aluminum, nickel, cobalt, magnesium, gold, silver, platinum, tungsten, chromium, manganese and mercury. We can distinguish two groups of metals: ferrous metals and nonferrous metals. The former contain mainly iron, but in the latter, the basic material is a metal other than iron.
Ferrous metals include cast iron; wrought iron and steels. There are several different grades of steels. We can classify them according to their carbon content:
Low-carbon steels 0.07 – 0.15% carbon.
Mild-steels 0.15 – 0.25% carbon.
Medium-carbon steels 0.25 – 0.50 % carbon.
High-carbon steels 0.50 – 1.40 % carbon.
Non-ferrous metals include copper, zinc, lead, tin, etc...
The physical properties of metals differ greatly, chiefly in density (comparative weight) strength, hardness, elasticity, melting and boiling points under heat, and electrical and heat conductivity. In order to obtain the properties desired, metals are often blended with other metals, or even with non-metals such as carbon or silicon. These blended metals are known as alloys. Non-ferrous alloys include brass which is made from copper and zinc and bronze which is made from copper and tin.
PROPERTIES OF MATERIALS
We use particular materials to produce certain objects because of their properties. How do we find out what the properties of some materials are? The answer is very simple. We can see the materials or touch them; we can try lifting them or applying force to them. When we touch the material, we can feel if it is smooth or rough, soft or hard. We need a crane to lift a concrete block as it is really heavy, but things we can lift with our hands are obviously light. We use concrete blocks for building constructions because they are rigid. But car wheels should be flexible; therefore, we use rubber for their production. We also have to mention plasticity and elasticity. A rubber band is elastic, and modelling clay is a plastic material. We want to see through windows, so we use glass to make them. Glass is transparent, but brittle, so it can be easily broken. Glass is not tough at all. Plastics are tough, but they are usually either translucent or opaque, so we cannot see clearly through objects made from them. Another important property in the building industry is combustibility. Materials can be combustible or noncombustible. We can also say that materials are flammable or nonflammable. Fire-resistant material will not burn in the process of combustion and that is the reason why fire-resistant doors
Other important properties are corrosion resistance, which means that materials are resistant against rust, and conductivity, which means that materials are good or poor conductors of electric current or heat. For building structures it is important to know if the material is permeable or impermeable, as builders don’t want moisture or water vapour to pass inside the building
smooth [smuːð] 1. 1) гладкий, ровный; скользкий (о поверхности)
rough 1) грубый; необработанный; черновой; приблизительный; шероховаты
rigid жёсткий; устойчивый
flexible ['fleksəbl] 1) гибкий; гнущийся; мягкий, эластичный
rubber 1) каучук; резина
plasticity [plæs'tɪsətɪ] 1) гибкость, пластичность, эластичность
elasticity [ˌɪlæs'tɪsətɪ] 1) эластичность; упругость
opaque [ə'peɪk] непрозрачный; непроницаемый, тёмный
translucent [trænz'luːsnt] полупрозрачный
transparent [trænz'pærnt] прозрачный, просвечивающий
tough [tʌf] прочный; жёсткий; тугой
combustibility [kəmˌbʌstə'bɪlətɪ] воспламеняемость, горючесть
combustible [kəm'bʌstəbl] 1. воспламеняемый, горючий
noncombustible несгораемый
flammable ['flæməbl] огнеопасный; легковоспламеняющийся
nonflammable невоспламеняющийся; огнестойкий
combustion [kəm'bʌsʧ(ə)n] горение, возгорание, сжигание
conductivity [ˌkɔndʌk'tɪvətɪ]; удельная проводимость; электропроводность
impermeable 1) непроницаемый, непромокаемый 2) плотный, герметичный (о шве)
permeable ['pɜːmɪəbl] проницаемый, проходимый, негерметичный, пропускающий
moisture ['mɔɪsʧə] влажность, сырость; влага, мокрота
water vapour водяной пар
Foundations
Foundations are designed by a geotechnical engineer to have an adequate load capacity with limited settlement; structurally, they are designed by structural engineers. The primary design concerns are settlement and bearing capacity. A foundation is a structure that transfers the loads of a superstructure to the earth. It supports and anchors a building or other structure. Geotechnical engineers investigate the soil and bedrock on and below a site to determine its engineering properties and how they will interact with the proposed construction. Geotechnical engineers then determine and design the types of foundations for structures such as high-rise buildings, bridges, and medium-to-large commercial buildings; they also work on smaller structures. Most foundations extend underground, and the foundations of large buildings often penetrate to the bedrock. The foundations built for above-ground structures include flat foundations (e.g., footings) and deep foundations (e.g., driven piles).
Planning and Building a House
There has recently been a boom in the building industry. Large investors and small private owners build new houses; in cities high-rise residential buildings are built; in the suburbs of the cities and villages, detached houses or bungalows are built. At the moment most cities in Slovakia look like a large building site. Cranes, piles of bricks, panels and other building materials are all over the place and often obstruct traffic.
The procedure for building a house is quite a complex one. Investors usually have an idea about the kind of house they want to build to meet their needs or that reflect current trends. First of all, they need a plot of land; then they should contact an architect, who will design the house. The architect, in cooperation with designers, draws preliminary plans to show the size of the house, the interior arrangement of the rooms and where all the fittings must go in the house. The architect can also give the client a rough estimate of the cost. The architect should cooperate with a surveyor, who will measure the plot of land or site. Together they will make a plan, and the investor should then apply for a planning permit to the local building authority. After receiving a permit for the construction the architect works out what will be needed to build the house and how much it will cost. At this stage the architect or the client himself should find a building contractor, also known as a builder. Several building contractors can be invited to submit their tenders. The client will choose the contractor offering the best quality for a reasonable price. The architect usually assists his client to draw up a contract with the building contractor. The builder is the one who manages the whole process of constructing a house. He has to hire independent crews known as subcontractors to perform various types of work, and he regularly submits their bills to the client.
At the very beginning the workmen on the building site mark the shape of the house with wooden pegs and tape. Everything is then ready for digging up the topsoil to prepare the site for laying the foundation. After the foundation is laid and set, the workmen put a waterproof layer on top of it to prevent moisture in the ground from passing to the rest of the house. Then the bricklayers can start building the walls. To make the walls stronger the bricks must overlap each other. This is called binding/bonding. When the vertical walls are built, the carpenters can begin their work. A carpenter is a man who does the rough woodwork on a house, e.g., he installs the beams and joists that hold the ceiling up. In most cases the walls of the house are too high for the bricklayers, carpenters and plasterers to reach, so a scaffold has to be made. A scaffold is a platform of planks for the workmen to stand on. It is held up by a framework of steel tubes. After that the tiler can fix the roof tiles onto the roof so that they overlap each other. When the roof is completed, the guttering and drainpipes are installed. They collect the rainwater that runs from the roof, and take it into the drains. A special crew then installs the windows. Once the house is covered with the roof and the windows are installed, many different workmen come and finish the house. Plumbers install water pipes to carry clean water into the house. They also lay pipes to carry waste water away to sewers. At the same time electricians can start their work as well. They fasten wires on the walls and put in all the lights and plug-sockets according to a special plan made by the draftsman. They have to observe special safety precautions. When all the wires and pipes are in place, the house is ready for the plasterers. They cover the walls and ceilings with plaster to form a hard and smooth surface and leave it to the painters and decorators to give the interior of the house its final appearance. After the interior of the house is completed, the facade is constructed.
When the house is completed, the client can occupy it. Construction contracts generally provide for various defects liability periods of six, twelve or eighteen months from completion. During this period the contractor must correct any defects that appear in the fabric of the building.
Roofs
A roof covers the top part of a building and protects it from the effects of weather, mainly rain, but it also protects the building from heat, sunlight, cold or wind. The characteristics of a roof depend upon the purpose of the building it covers, the available roofing materials and the local traditions of construction and concepts of architectural design and practice.
There are three elements to consider in a roof design: the available material, construction of the building and durability. The material of a roof may vary from wooden shingles or the bark of certain trees to slate, sheet metal and pre-cast concrete or ceramic tiles. Ceramic tiles have been the predominant roofing material for centuries. The construction of a roof is determined by its method of support, how the space underneath it is bridged and whether or not the roof is pitched. The pitch is the angle at which the roof rises from its lowest to highest point. Most roofs are sloped or pitched. The durability of a roof is a matter of concern because the roof is often the least accessible part of a building for purposes of repair and renewal, while its damage or destruction can have serious effects.
Over the centuries, roof-building techniques have been refined to yield roofs of considerable strength and durability. A wide variety of materials have been developed, and homeowners have a vast selection of materials, colors, prices, and other choices. A contemporary roof, regardless of the shape or surface material, consists of a large number of components: wood framing, sheathing, underlayment, flashing, gutters, and, of course, the shingles or other finished surface. The supporting structure of a roof usually comprises beams that are long and made of strong, fairly rigid material such as timber, cast iron or steel. Steel girders became the major structural support for large roofs. Nearly all roofs are framed using one of two methods: standard “stick” framing or newer “truss” framing. Stick-framed roofs utilize individual rafters that span from the top of the exterior walls to the ridge. Truss-framed roofs are built from triangular-shaped, pre-made truss units.