Roof, covering of the top of a building, serving to protect against rain, snow, sunlight, wind, and extremes of temperature. Roofs have been constructed in a wide variety of forms—flat, pitched, vaulted, domed, or in combinations—as dictated by technical, economic, or aesthetic considerations. In most cases roofs has been clad with local materials. In northern Europe this is traditionally straw, wooden boards, Grass, wooden splinters etc. and in more costly buildings slates or tiles.Sloping roofs come in many different varieties. The simplest is the lean-to, or shed, which has only one slope. A roof with two slopes that form an “A” or triangle is called a gable, or pitched, roof. This type of roof was used as early as the temples of ancient Greece and has been a staple of domestic architecture in northern Europe and the Americas for many centuries. It is still a very common form of roof. A hip, or hipped, roof is a gable roof that has sloped instead of vertical ends. It was commonly used in Italy and elsewhere in southern Europe and is now a very common form in American houses. Gable and hip roofs can also be used for homes with more complicated layouts. The gambrel roof is a type of gable roof with two slopes on each side, the upper being less steep than the lower. The mansard roof is a hipped gambrel roof, thus having two slopes on every side. It was widely used in Renaissance and Baroque French architecture. Both of the aforementioned roof types can provide extra attic space or other room without building an entire additional floor. They can also have a strong aesthetic appeal. Roof tiles is made from local clays and have colour from the chemical composition from where they clay is dug up. Traditionally local variations is red and yellow depending of amount of calcium in the clay but there is variations of brown and grey also depending on oxygen reduction in the burning process. Form of tiles differ because of local traditions. Slate is available in both northern France/Belgium, Spain and in Wales. The both latter has been exporting slates all over Europe since at least the 16th century. The Welsh slate has been highly valued because of it thiness(3–8mm) and durablility.