A cap sheet is a type of roofing membrane that is used as the top layer of a built-up roofing system. Cap sheets are typically made from asphalt-saturated felt or other materials, and are designed to provide a durable and waterproof surface that can withstand the elements and other types of damage.
The cap sheet is installed over the base layer of the built-up roofing system, and is typically fastened with hot asphalt or other adhesive materials. The sheet is then covered with a layer of gravel or other ballast to protect it from damage and improve its durability and performance.
The cap sheet is an important component of the overall roofing system, as it provides the final layer of protection against the elements and other types of damage. The sheet is designed to be durable and long-lasting, and can help to prevent water infiltration and other types of damage that can compromise the overall performance and longevity of the roof system.
Proper installation and maintenance of the cap sheet, along with regular inspections and repairs, can help to ensure the continued durability and performance of the roof system. The sheet must be properly integrated with other roof components, such as flashings and drainage systems, and must be installed in a way that provides a secure and watertight seal against water infiltration and other types of damage.