Roofing paper, also known as roofing felt or underlayment, plays a crucial role in protecting roofs from moisture, wind, and other environmental factors. Homeowners and roofing professionals in the United States rely on various types of roofing paper to enhance the durability and lifespan of roofing systems. This article explores the different kinds of roofing paper, their materials, benefits, and ideal applications, helping readers make informed decisions for their roofing needs.
| Type of Roofing Paper | Material | Thickness | Key Benefits | Common Uses |
|---|---|---|---|---|
| Asphalt-Saturated Felt | Organic or fiberglass base with asphalt coating | 15 lb or 30 lb | Water-resistant, economical, easy to install | Under shingles on residential roofs |
| Synthetic Roofing Underlayment | Polypropylene or polyester fabric | Varies, typically lighter than felt | High tear resistance, lightweight, UV-resistant | Under metal, tile, or shingle roofs |
| Rubberized Asphalt Underlayment | Rubberized asphalt with film backing | Thicker, self-adhering | Superior waterproofing, adhesion to roof deck | Low-slope roofs, high-risk leak areas |
| Organic Felt | Wood pulp or cellulose fibers saturated with asphalt | Usually 15 lb or 30 lb thickness | Economical, traditional choice | Residential roofing underlayments |
What Is Roofing Paper and Why Is It Important?
Roofing paper acts as a secondary barrier beneath shingles or roofing tiles, protecting the roof deck from moisture infiltration and weather damage. It prevents water from leaking into the interior in case the primary roofing material fails or during intense weather events. Roofing paper also helps protect the wooden structure by reducing condensation buildup, which can lead to mold and rot.
In addition to moisture protection, roofing paper enhances fire resistance, improves the roof’s lifespan, and provides a smoother surface for shingles installation. Various types of roofing paper are available depending on the roofing material, climate considerations, and budget.
Asphalt-Saturated Felt: The Traditional Choice
Asphalt-saturated felt, commonly referred to as roofing felt, is among the most widely used types of roofing paper in residential construction. It comes in two primary grades—15 lb and 30 lb—indicating the weight per square foot and correlating to thickness and durability.
Material Composition
Manufactured by saturating organic felt or fiberglass mats with asphalt, this roofing paper provides water-resistant properties. Organic felts are made from wood pulp or cellulose fiber, while fiberglass felts use a glass fiber mat for more durability and moisture resistance.
Benefits
- Cost-effective underlayment for moderate climates
- Easy to cut and install
- Compatible with many types of roofing materials
- Offers good protection against drips and leaks during installation
Limitations
Asphalt-saturated felt can tear easily and degrade under direct sunlight over extended periods. Organic felts tend to absorb moisture, which can weaken their performance.
Synthetic Roofing Underlayments: Modern and Durable
Synthetic roofing underlayments are made from polypropylene or polyester fabrics coated with polymers, offering significant advantages over traditional felt.
Advantages of Synthetic Underlayment
- Lightweight and easy to handle
- Superior tear and puncture resistance
- Longer UV exposure capabilities, maintaining integrity during prolonged installation
- Better water and vapor resistance
- Slip-resistant surfaces improve safety for roofing contractors
Common Applications
Synthetic underlayments are ideal under a variety of roofing materials, including metal, tile, and asphalt shingles. They are favored in regions with harsh weather conditions or longer roof exposure times.
Rubberized Asphalt Underlayment: Premium Waterproof Protection
Rubberized asphalt underlayment features a thick layer of rubberized asphalt bonded to a polyethylene film backing, often designed as a self-adhering membrane.
Key Features
- Outstanding waterproofing, sealing around nails and fasteners
- Self-adhesive for strong bond to the roof deck
- Excellent durability in high-moisture or low-slope roofing conditions
- Provides ice and water shield protection in vulnerable roof areas
Ideal Uses
This premium underlayment is particularly useful in areas prone to ice dams, heavy rain, or flat roofs that require superior moisture barriers. It is often installed in valleys, eaves, and around penetrations for enhanced leak protection.
Organic Felt Roofing Paper: Traditional and Affordable
Organic felt is a natural material made from wood cellulose, saturated with asphalt, representing the traditional form of roofing paper.
Characteristics
- Generally available in 15 lb or 30 lb weights
- Good water resistance but prone to absorbing moisture which can lead to swelling
- Less durable than fiberglass or synthetic options under extreme weather
Usage Considerations
While still in use, organic felt is increasingly replaced by synthetic and fiberglass felts due to its susceptibility to mold and slower drying times after exposure to water.
Additional Roofing Paper Types and Innovations
Fiberglass-Based Roofing Felt
Fiberglass felt contains glass fibers for reinforcement, enhancing tensile strength and moisture resistance, making it less prone to tearing compared to organic felt.
Composite Underlayments
Composite roofing underlayments combine layers of synthetic materials with asphalt felt or rubberized membranes to optimize waterproofing, durability, and ease of installation.
Eco-Friendly Roofing Papers
Recent innovations have introduced recycled and environmentally sustainable roofing paper options, reducing workplace hazards and promoting greener construction practices.
Selecting the Right Roofing Paper for Your Project
Choosing the proper roofing paper involves assessing several factors including climate, roof slope, budget, and roofing material compatibility.
Considerations for Selection
- Climate: Wet or snowy regions benefit from rubberized or synthetic waterproof underlayments.
- Roof Slope: Low-slope roofs require higher waterproofing standards, often rubberized membranes.
- Budget: Asphalt felt offers cost savings but less durability.
- Roofing Material: Some roofing materials require specific underlayment properties for adherence and performance.
Installation Tips
Ensuring proper installation, such as overlapping seams correctly and securing the paper without damaging it, is critical for optimal protection regardless of the roofing paper type chosen.
Maintenance and Longevity of Roofing Paper
While roofing paper is typically covered by the primary roofing material, its condition impacts overall roof health. Regular roof inspections can help detect issues before they escalate.
Tips for Maintaining Roofing Paper Effectiveness
- Inspect for damage after severe weather
- Ensure proper ventilation to reduce moisture buildup
- Address any leaks or punctures in the roofing surface promptly
- Use high-quality products and experienced installers for maximum lifespan
Conclusion
Understanding the types of roofing paper available and their distinct features allows homeowners and contractors to select the most appropriate underlayment for any roofing project. From traditional asphalt-saturated felt to advanced synthetic and rubberized options, the choice directly affects roof performance and durability. Making an informed decision ensures a robust roof that protects your home or building effectively for decades.