This starter strip (also known as underlayment or base strip) is designed for the initial course when installing asphalt (flexible) shingles. It is manufactured on a strong and durable fiberglass base, which is coated with a layer of high-quality bitumen. This combination of materials provides the product with high tensile strength, the necessary flexibility for installation on complex roof sections, excellent elasticity, and absolute waterproofing.
Purpose and Application:
The primary purpose of the element is to create a reliable sealing barrier at the lowest point of the roof slope (often along the eave edge). Its installation prevents capillary action and the backflow of water (underflow) under the main roofing material of asphalt shingles during heavy rain or ice dam formation. Installing the starter strip is a mandatory initial step in creating a correct roofing system with flexible shingles, ensuring the longevity and reliability of the entire structure.