Having a roof over your head is a sign of shelter. Roofs are like hats over the spaces we live. Roofs, first and foremost, keep us dry. They work to shed rainfall from coming into our homes and buildings. A roof is part of an enclosure system. It’s the lid on the top part of a building or structure which provides security from animals and weather, particularly rainfall or snowfall, but also wind, heat and sunlight. Roofs vary in their response to climate. For example, roofs are pitched to shed rain and snow in areas where precipitation is high. Where it is very arid and dry, a building top can be flat and serve as an airing porch to catch breezes. In addition to climate response, roofs also respond to function or use. For instance, a factory roof will probably look different than the one on your house. A library roof could be different than a government building. The types of roofs respond to available construction materials and to local traditions of making. Roofs also follow local and national building codes. Roofs may also cover porches and open air pavilions. Botanical gardens and greenhouses have glass roofs that let in the sunshine. Roofs are an essential element of shelter as well as a cultural expression of construction technique. Keep a roof overhead!