Asphalt felt underlayment used in tile roof systems should comply with which standard and type?

• A. ASTM D4869, Type IV
• B. ASTM D226, Type I
• C. ASTM D226, Type II
• D. ASTM D226, Type III

Answer: (A)

In tile roof systems, the underlayment must be a heavy-duty material that can resist tearing, puncture, and wind uplift while providing a reliable moisture barrier. The standard to use is ASTM D4869, which specifically covers asphalt-saturated felts used as underlayment for roofing. Among the types defined in that standard, the heaviest, Type IV, is designed for demanding installations like tile and metal roofs. It offers higher thickness, greater tear resistance, and more asphalt saturation, giving better protection under tile against punctures and leaks.

D226 is an older specification and does not align with the current practice for tile roof underlayment, which is why it’s not the preferred choice here. The lighter types (I, II, III) are not sufficient for tile systems, where extra durability is needed.