became common during the Neolithic (see Neolithic architecture). Types Residential Single-family residential buildings are most often called houses or homes. Multi-family residential buildings containing more than one dwelling unit are called a duplex or an apartment building. A condominium is an apartment that the occupant owns rather than rents. Houses may also be built in pairs (semi-detached), in terraces where all but two of the houses have others either side; apartments may be built round courtyards or as rectangular blocks surrounded by a piece of ground of varying sizes. Houses which were built as a single dwelling may later be divided into apartments or bedsitters; they may also be converted to another use e.g. an office or a shop. hotels, especially of the extended stay variety (like apartels) can also be classed as residential. Building types may range from huts to multimillion-dollar high-rise apartment blocks able to house thousands of people. Increasing settlement density in buildings (and smaller distances between buildings) is usually a response to high ground prices resulting from many people wanting to live close to work or similar attractors. Other common building materials are brick, concrete or combinations of either of these with stone. Residential buildings have different names for their use depending if they are seasonal include holiday cottage (vacation home) or timeshare; size such as a cottage or great house; value such as a shack or mansion; manner of construction such as a log home or mobile home;, architectural style such as a mock castle or Victorian house, proximity to the ground or water such as Earth sheltering the earth sheltered house, stilt house, or houseboat \ floating home. Also if the residents are in need of special care, or society considers them to dangerous to have freedom, there's residential total institutions such as nursing homes, orphanages, psychiatric hospitals or prison; or in group housing like barracks or dormitories. Historically many people lived in communal buildings called longhouses, smaller dwellings called pit-houses and houses combined with barns sometimes called housebarns. Buildings are defined to be substantial, permanent structures so other dwelling forms such as yurts, and motorhomes are dwellings but not buildings. Commercial A commercial building is one in which at least one business is based, but where people don't live. Examples include stores, restaurants, and hotels. Industrial Industrial buildings are those in which heavy industry is done, such as manufacturing. These edifices include warehouses