This construction material, commonly available at large home improvement retailers, functions as an underlayment. It is installed beneath roofing shingles or other exterior cladding to provide a protective barrier against moisture. The “15 lb” designation refers to the approximate weight per 100 square feet, indicating its thickness and durability.
The material’s significance lies in its ability to prevent water damage to the underlying roof deck, extending the roof’s lifespan and protecting the building’s interior. Its widespread use stems from its cost-effectiveness and ease of installation, making it a standard component in residential and commercial construction. Historically, it has served as a reliable method for safeguarding structures from the elements.
