Roofing is the process of covering the roof of a building with shingles. Asphalt is an organic bituminous material that is used to make composition shingles. ASTM International is a voluntary organization that creates standards, testing procedures, and specifications for the industry. Its standards are used by many city building codes. Asphalt roofing is the most commonly used type of roof covering. Roofing materials are made of a variety of different materials.
Roof coverings depend on the type of material that is available. Many vernacular structures, especially in Asia, utilize vegetation. Sea grass is one of the most durable roofing materials available, and bamboo is commonly used in many parts of the world. Split bamboo stems are laid alternately or overlapped to make a roofing layer. In areas with abundant timber, wooden shingles are also used. Other natural roofing materials include bark and sea grass. Roofing materials vary, so the choice of material will depend on the climate.
Sloped roofs require multiple layers of materials. The top layer is known as the decking, and the middle layer is called the underlayment. Underlayment is used on roofs that are low-sloped or in high-water areas, where shingles might be prone to buckling. In these situations, the underlayment will prevent the roof from warping and will prevent it from being damaged by high-intensity sunrays.