Roofing Underlayment (Felt vs. Synthetic)

Standard felt paper, also known as 15# roofing felt or tar paper, has been a staple for roofing contractor underlayment for many years. It’s typically made from organic materials like cellulose (often recycled paper) or fiberglass, saturated with asphalt or bitumen to make it waterproof. Felt paper is available in various weights, with heavier weights providing better durability and protection.

Synthetic roofing underlayment, on the other hand, is a newer option in the roofing industry. It’s typically made from polymer materials such as polyethylene or polypropylene. Synthetic underlayment is engineered to be lightweight, durable, and highly resistant to tearing, UV exposure, and moisture penetration.

Felt vs. Synthetic: Key Differences

• Durability: Synthetic underlayment is generally more durable than standard felt paper. It is less likely to tear during installation or under extreme weather conditions, such as high winds.
• Water resistance: Both types are water-resistant, but synthetic tends to offer better resistance to moisture penetration over time and does not absorb water like felt paper can.
• UV resistance: Synthetic underlayment has better UV resistance, meaning it is less likely to degrade when exposed to sunlight over time.
• Weight and handling: Synthetic underlayment is lighter and easier to handle, making installation quicker and less physically demanding.
• Cost: Synthetic underlayment has a higher upfront cost, but its superior durability may lead to long-term savings by reducing the need for repairs or replacements.

Which Underlayment Is Right for Your Minnesota Roof?

While both felt paper and synthetic underlayment protect the roof deck, synthetic generally offers superior durability, water resistance, UV resistance, and ease of installation. In Minnesota’s climate — with harsh winters, ice dams, freeze-thaw cycles, and summer hailstorms — synthetic underlayment is often the better long-term investment.

Northern Exteriors MN has been installing roofs across the Twin Cities since 2001. We use high-quality synthetic underlayment on our roofing projects because we believe in doing the job right the first time. MN License #BC297099.

Call today for a free roof inspection and quote: 651-230-5103