Synthetic Underlayment
A woven or non-woven polypropylene sheet used as an alternative to traditional felt underlayment.
How It Compares to Felt
Synthetic underlayment is a woven or spun-polymer sheet that replaces traditional asphalt-saturated felt paper beneath the shingles. It's lighter (a roll covers more area with less weight, meaning fewer roof-loading trips), tears and UV-degrades far less if exposed during installation delays, and provides significantly better foot traction for installers on steep pitches — which reduces installation defects from crews working on a slick surface.
Why It's Now the Ohio Standard
Felt absorbs water and can wrinkle, telegraphing an uneven surface up through the shingles over time, and it tears easily in the wind gusts common during a Fairfield County spring installation. Synthetic underlayment resists both problems and typically carries manufacturer coverage of 25–50 years versus felt's much shorter functional life — it costs modestly more per square but essentially every reputable installer in the area has made it the default rather than an upgrade option.