Synthetic Roof Underlayment
A woven polypropylene sheet installed over roof sheathing as a secondary weather barrier beneath shingles or metal roofing. Lighter, stronger, and more tear-resistant than traditional felt paper.
In Detail
Synthetic underlayment has largely replaced #15 and #30 felt in professional roofing. It lies flatter, resists tearing during installation, is UV-stable for 4–6 months of exposure, and is lighter to carry. It's also less likely to wrinkle and telegraph through thin shingles. Applied with cap nails or staples. Note: it is NOT a substitute for ice & water shield — it doesn't self-seal around fasteners.