Roof Underlayment (Synthetic): Complete Buying Guide 2026
Synthetic roof underlayment is a water-resistant barrier installed under roofing materials. It is lighter, stronger, and more tear-resistant than traditional felt paper, providing critical secondary weather protection. In 2026, roof underlayment (synthetic) prices average $0.25 per sq ft, with a typical range of $0.15 to $0.45 depending on your region, supplier relationships, and order quantity.
When budgeting for a project using roof underlayment (synthetic), factor in approximately 10% additional material for waste, plus labor costs averaging $0.15 per sq ft for professional installation. A typical project using this material runs approximately $750 including both materials and labor.
With an expected lifespan of 30 years, roof underlayment (synthetic) represents a cost of approximately $0.01 per sq ft per year of service life. This solid lifespan provides good value for most residential and commercial applications.