In roofing, a base-ply sheet is a type of roofing membrane that is used as a base layer for the installation of built-up roofing systems. Base-ply sheets are typically made from asphalt-saturated felt, which is reinforced with fiberglass or other materials to provide additional strength and durability.
The base-ply sheet is installed over the roof deck, and is typically fastened with nails or other mechanical fasteners. The sheet is then covered with layers of hot asphalt or other adhesive materials, along with additional layers of felt or other roofing membranes, to create a built-up roofing system.
The base-ply sheet is an important component of the built-up roofing system, as it provides a strong and stable base for the additional layers of roofing materials. The sheet also helps to prevent water infiltration and other types of damage, and can improve the overall durability and performance of the roof system.
Proper installation and maintenance of the base-ply 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 must be installed in a way that provides a secure and watertight seal against water infiltration and other types of damage.