3 BUILDING MATERIALS NATURAL MATERIALS (1) Which nomadic people lived in tepees? Do you think building materials are different in different geographical areas? Give examples. Tepee: conical tent used by Native Americans. Yurt: circular tent used in the steppes of Central Asia. Tensile architecture is a structural system that predominantly uses tension instead of compression. ONLINE RESOURCES Yurts cable: cavo coolness: frescura dry-stone: (muri) a secco fabric: stoffa framework: struttura gravel: ghiaia hardness: durezza heat: calore long-lasting: di lunga durata mortar: malta di calce reed: canna, giunco straw: paglia tensile architecture: tensostrutture thatched: di paglia unprocessed: non lavorato 76 Two groups of building materials Building materials can be generally categorized into two groups, natural and synthetic or man-made. Natural building materials are those that are unprocessed or minimally processed by industry, such as wood. Fabric Tents used to be home for nomadic groups all over the world. Two wellknown types of tent are the conical tepee and the circular yurt . The tent has been revived as a construction technique, with the development of tensile architecture and synthetic fabrics. Modern buildings can include flexible materials such as fabric membranes supported by a system of steel cables, a rigid framework or internal air pressure. Mud and clay The amount of each of the two materials used usually depends on the quality of the soil used. The other main ingredients can include sand and/or gravel. Soil and especially clay is good at keeping temperatures at a constant level. Homes built with earth tend to be naturally cool in the summer and warm in cold weather. Clay retains heat or cold, releasing it over a period of time, like Rural mud house in India BIO AND MAN-MADE CONSTRUCTIONS Interior of a rock house in Matera stone. Walls change temperature slowly, so artificially raising or lowering the temperature can take longer than in a wooden house, but the heat and the coolness will stay longer. Rock Rock structures have always existed. It is the longest-lasting building material and is usually readily available. There are many types of rock, all with different properties making them better or worse for different uses. Rock is a very dense material so while it can offer a lot of protection, its main disadvantage as a building material is its weight and hardness. In addition, stone is hard to keep warm without using large amounts of heating resources. Drystone walls, that is to say, walls with no joining material (or mortar) between the individual stones, have been built for an incredibly long time. Different forms of mortar can of course be used to hold the stones together, and cement is the most common now. Thatch This is one of the oldest building materials known. Straw and reeds together are good insulators and are available nearly everywhere. In Europe, thatched roofs on homes were once common but the material was gradually abandoned as industrialization and transport increased the availability of other materials.