Saturated Felt

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Saturated Felt

What is Saturated Felt?

An asphalt-impregnated felt material used as roofing underlayment to provide secondary water protection beneath primary roofing materials.

Description

Saturated felt is an asphalt-impregnated felt material used as roofing underlayment to provide secondary water protection beneath primary roofing materials such as shingles, tiles, or metal roofing. This essential building component consists of organic or fiberglass felt that has been saturated with asphalt to create a water-resistant barrier that protects the roof deck from moisture infiltration while allowing the roof system to breathe and release trapped moisture. Saturated felt serves as a critical backup protection system that prevents water damage in case primary roofing materials fail or allow water penetration, making it a fundamental component in roofing systems where reliable weather protection is essential for building integrity and occupant safety.

Saturated felt is utilized in various roofing applications including residential shingle roofs where it provides underlayment protection for asphalt, wood, or composite shingles, tile roofing systems where felt creates a secondary barrier beneath clay or concrete tiles, metal roofing installations where underlayment prevents condensation and provides backup water protection, low-slope roofing where saturated felt may serve as a base layer for built-up roofing systems, re-roofing projects where new underlayment is installed over existing roof decks, and specialty applications such as shed roofs, dormers, or architectural features where reliable underlayment is needed. Each application requires appropriate felt grades, installation methods, and integration with other roofing components.

The construction and properties of saturated felt include the base material, typically organic felt made from recycled paper and wood fibers or fiberglass mat that provides dimensional stability, asphalt saturation that impregnates the felt to create water resistance while maintaining flexibility, surface treatments that may include mineral granules or other coatings to improve durability and UV resistance, perforations or micro-perforations that allow moisture vapor transmission while blocking liquid water, and reinforcement materials that enhance tear resistance and installation durability. Proper felt construction ensures effective water protection while allowing proper moisture management.

FAQs

  • What is saturated felt?

    Saturated felt is an asphalt-impregnated felt material used as roofing underlayment to provide secondary water protection beneath primary roofing materials.

  • What’s the difference between 15-pound and 30-pound felt?

    The numbers refer to weight per 100 square feet, with 30-pound felt being heavier, more durable, and providing better protection than 15-pound felt.

  • Is saturated felt waterproof?

    Saturated felt is water-resistant rather than completely waterproof, designed to shed water while allowing some moisture vapor transmission.

  • How is saturated felt installed?

    Saturated felt is installed starting at the eaves, working toward the ridge with proper overlaps, and secured with roofing nails or staples.

  • Can saturated felt be left exposed?

    Saturated felt should not be left exposed for extended periods as UV exposure and weather can degrade the material and reduce its effectiveness.

  • What’s the difference between organic and fiberglass felt?

    Organic felt uses recycled paper fibers while fiberglass felt uses a fiberglass mat base, with fiberglass typically offering better dimensional stability.

  • Is saturated felt required by building codes?

    Most building codes require some form of underlayment beneath roofing materials, with saturated felt being one acceptable option.

Fun Fact

Fun Fact: Saturated felt was first developed in the early 1900s as a replacement for wooden roof sheathing boards, revolutionizing roofing by providing a continuous, flexible underlayment that could conform to roof contours.

CSI Code

07 22 00

NAHB Code

730