When homeowners look at their roof, they usually see shingles. But underneath those shingles is another important layer that helps protect your home from moisture: roof underlayment. Although it's hidden from view, underlayment plays an important role in the overall performance and durability of your roofing system. What Is Roof Underlayment? Roof underlayment is a protective material installed between the roof decking and the shingles. It provides an additional barrier again