Calder Standard Building Paper Grade A1F Lead Underlay is a high-quality construction material designed to provide an effective secondary barrier beneath lead roofing installations. Manufactured to meet rigorous industry standards, this durable building paper protects against moisture ingress and enhances the longevity of lead coverings. Supplied in a convenient 25m x 1m roll, it is easy to handle and install on site. Suitable for various roofing and cladding applications, Calder Grade A1F Lead Underlay delivers reliable performance in both commercial and residential construction projects.