Roofing Materials

What Is Felt Underlayment?

Felt underlayment is a traditional asphalt-saturated layer installed between the roof deck and roof covering.

Understanding Felt Underlayment

Felt Underlayment: Felt underlayment is a traditional asphalt-saturated layer installed between the roof deck and roof covering.

Published: June 4, 2026 Reviewed: June 4, 2026 Updated: June 4, 2026 By Exterior Echelon

Felt underlayment is a traditional asphalt-saturated sheet material installed over the roof deck before shingles or other roof coverings.

Why It Matters

Underlayment adds a secondary layer of protection beneath the main roof covering and helps protect the deck during installation.

Common Problems

Common issues include wrinkling, tearing, poor overlap, weather exposure before shingles are installed, and using the wrong underlayment for the roof system.

Building Codes & Industry Standards

Felt underlayment should meet applicable underlayment requirements and be installed with proper overlaps, fastening, and slope considerations.

Exterior Echelon Notes

Exterior Echelon explains underlayment choices because homeowners usually see shingles first, but the layers underneath also matter.

Felt underlayment installed over roof decking
Felt underlayment is a traditional layer beneath roof coverings.

Related Terms

Continue learning with connected glossary definitions.

Underlayment

Roof Components

Underlayment is a protective layer installed between the roof deck and the outer roofing material.

Synthetic Underlayment

Roofing Materials

Synthetic underlayment is a modern roofing underlayment made from engineered materials rather than traditional felt.

Ice & Water Shield

Roof Components

Ice and water shield is a self-adhering waterproof underlayment used in vulnerable roof areas such as eaves, valleys, and penetrations.

Roof Decking

Roof Structure

Roof decking, sometimes called the roof deck, is the sheathing or board material that forms the base layer of the roof system.

3-Tab Shingle

Roofing Materials

A 3-tab shingle is a flat asphalt shingle with cutouts that create the appearance of three separate tabs.

Actual Cash Value (ACV)

Insurance & Claims

Actual Cash Value, or ACV, is an insurance valuation that generally reflects replacement cost minus depreciation.

Glossary Note

This glossary is provided for general homeowner education. Actual roofing, siding, gutter, window, and exterior remodeling conditions should be evaluated by a qualified contractor before making repair, replacement, or insurance claim decisions.

Frequently Asked Questions

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