Roofing Glossary

Synthetic Underlayment

Synthetic underlayment is the modern alternative to asphalt felt, made from woven or spun polymers like polypropylene. It does the same job — a water-resistant layer between decking and shingles — but it is lighter, dramatically more tear-resistant, and far more forgiving during installation.

Because synthetics do not absorb water, they lie flat even if caught by rain before shingles are installed, and their high tear strength means they stay put in wind during the roofing process. They also provide better walkability for crews on steep slopes.

Synthetic underlayment costs more per roll than felt, but on a whole-roof basis the difference is modest — and it is now the default choice for most quality-minded contractors.

Why It Matters

Underlayment is one of the easiest quality upgrades in a roofing quote. If your contractor includes synthetic underlayment as standard, that is a good sign about their overall approach.

Questions about your own roof? Request a free estimate or call Nucci Brothers Roofing at (301) 458-1003.