Felt Underlayment

Felt underlayment is defined as a traditional asphalt-saturated paper product installed over the roof deck and beneath the shingles to provide a secondary moisture barrier. Available in 15-pound and 30-pound weights per 100 square feet, felt underlayment has been the industry standard for over a century. While still code-compliant, felt underlayment has been increasingly replaced by synthetic underlayment, which offers superior tear resistance, UV stability, and moisture protection.