Master Craftsman Shingle Applicators Manual Practice Test 2026 - Free Shingle Application Practice Questions and Study Guide

Underlayment on a roof is a protective layer laid over the deck before shingles. An organic fiber mat impregnated with asphalt describes roofing felt. The organic fibers provide structure, while the asphalt saturates the mat to create a water-resistant barrier that helps shed moisture, protects the deck, and aids in sealing around nails. This material is commonly sold as tar paper or roofing felt and is rolled out across the roof. It differs from fiber glass mat, which is an inorganic base used in some shingles, and from downspout or eaves flashing, which are metal components of drainage and flashing rather than underlayment.