Choosing the best felt paper for roofing is critical for ensuring a weather-resistant, durable underlayment beneath your shingles. Felt paper acts as a moisture barrier, protecting your roof deck from water infiltration and increasing overall roof longevity. This article explores various types of felt paper, their benefits, and expert recommendations to help homeowners and contractors make informed decisions when selecting roofing felt.
| Felt Paper Type | Weight (lbs) | Material | Primary Benefits | Typical Use |
|---|---|---|---|---|
| 15 lb Felt | 15 | Organic or Synthetic | Basic moisture protection, cost-effective | Residential roofs, low-slope applications |
| 30 lb Felt | 30 | Organic or Synthetic | Enhanced durability and tear resistance | Steeper pitch roofs, higher exposure areas |
| Synthetic Felt | Varies (usually lighter) | Polypropylene or Polyester | High tear resistance, water-shedding, lightweight | Modern roofing, long-lasting underlayment |
| Rubberized Asphalt Felt | Varies | Rubberized Asphalt | Superior waterproofing, self-sealing properties | Ice dam protection, critical areas |
What Is Roofing Felt Paper and Why Is It Important?
Roofing felt paper serves as a secondary layer beneath shingles, functioning primarily as a water-resistant barrier. Traditionally made from organic materials saturated with asphalt, felt paper helps prevent water intrusion caused by rain or ice dams. In addition to moisture protection, it offers a vapor barrier, adds fire resistance, and shields against wind-driven rain. Installing quality felt paper properly extends the lifespan of your roof by protecting the wooden decking.
Types of Felt Paper for Roofing
Organic Felt Paper
Organic felt is constructed from cellulose-based materials like wood fibers and recycled paper. It is saturated with asphalt to impart waterproof qualities. While this felt is absorbent and heavy, it provides excellent adhesion for roofing adhesives and sealants. Organic felt typically comes in 15 lb and 30 lb weights, with the heavier variant being more durable and resistant to tearing during installation.
Synthetic Felt Paper
Made from woven or nonwoven polypropylene or polyester fibers, synthetic felt is lightweight and highly resilient. Unlike organic felt, synthetic versions do not absorb water, allowing for better water shedding. They resist tearing, UV damage, and often have slip-resistant surfaces. Synthetic felt is becoming the preferred choice in modern roofing because of its durability and ease of handling.
Rubberized Asphalt Felt
This felt incorporates rubberized asphalt, creating a self-adhering, waterproof barrier. It is commonly used in vulnerable roof areas prone to ice dams, valleys, and eaves. Rubberized asphalt felt offers excellent waterproofing and sealing properties, allowing it to fill nail holes and minor gaps, acting as an extra layer of protection against leaks.
Comparing 15 lb vs. 30 lb Roofing Felt
| Feature | 15 lb Felt | 30 lb Felt |
|---|---|---|
| Weight | Lighter, easier to handle | Heavier, more durable |
| Thickness | Thinner | Thicker |
| Tear Resistance | Less resistant | Improved resistance |
| Cost | More affordable | More expensive |
| Typical Use | Low-slope roofs or budget projects | Standard residential and commercial roofs |
While 15 lb felt is economical for smaller projects and less demanding climates, most professionals recommend 30 lb felt for enhanced durability and long-term protection.
Benefits of Choosing High-Quality Synthetic Felt Paper
- Superior Durability: Synthetic felt resists tearing and degradation better than organic materials.
- Water Resistance: Non-absorbent fibers improve water shedding and reduce moisture retention.
- Lightweight and Easy Handling: Lighter rolls simplify installation, reducing labor time.
- UV Resistance: Maintains integrity longer if exposed before shingle installation.
- Slip Resistance: Textured surfaces improve safety for roofing contractors.
- Environmental Considerations: Some synthetic felt is made from recyclable materials and lasts longer, reducing waste.
Best Uses of Rubberized Asphalt Felt Paper
Rubberized asphalt felt is commonly applied in critical roofing areas where water exposure is concentrated. Features include:
- Self-Adhering Properties: Bonds tightly to roof decks creating a waterproof seal.
- Ice Dam Protection: Prevents leaks caused by ice buildup on roof edges.
- Sealing Nail Penetrations: The rubberized layer seals around nails and fasteners reducing leak points.
- Common Application Zones: Roof valleys, ridges, eaves, and around chimneys or skylights.
Due to its premium performance and cost, rubberized asphalt felt is best utilized selectively rather than as full roof underlayment.
How to Select the Best Felt Paper for Your Roofing Project
Choosing the right felt paper depends on several factors, including climate, roof slope, budget, and roof design. Consider these critical aspects:
- Climate and Weather Exposure: High rainfall or snow areas benefit from heavier 30 lb or synthetic felt.
- Roof Pitch: Steeper roofs require more durable underlayment for safety and performance.
- Installation Duration: Synthetic felt endures longer during extended construction timelines.
- Budget Restrictions: Organic felt is cost-effective but may have shorter lifespan.
- Manufacturer Compatibility: Some roofing shingle warranties specify certain underlayment types.
Reviewing these considerations will ensure optimal roof protection and adherence to roofing codes.
Tips for Proper Installation of Felt Paper Roofing Underlayment
- Start at the Eave: Roll felt horizontally from the bottom edge moving upward to direct water flow properly.
- Overlap Edges: Ensure at least 2-4 inches overlap on horizontal seams and 6 inches on vertical seams to prevent leaks.
- Use Correct Fasteners: Employ galvanized roofing nails with plastic caps to secure felt without tearing.
- Avoid Wrinkles and Bubbles: Smooth felt flat against the roof deck to maintain waterproof integrity.
- Follow Manufacturer Guidelines: Comply with installation instructions for maximum benefit and warranty adherence.
Common Roofing Felt Paper Brands and Their Features
| Brand | Material | Weight Options | Notable Features |
|---|---|---|---|
| GAF Tiger Paw | Synthetic | 40 lb | Slip-resistant, UV stable, lightweight |
| Owens Corning FeltBuster | Synthetic | 30 lb | Water resistant, mold and tear resistant |
| CertainTeed DiamondDeck | Synthetic | 30 lb | Lightweight, enhanced durability, UV resistant |
| Henry Blueskin | Rubberized Asphalt | N/A (Roll thickness varies) | Self-adhering, waterproof, ideal for flashings |
| Atlas Asphalt Felt | Organic | 15 lb, 30 lb | Traditional asphalt-saturated felt paper |
Environmental Impact and Sustainability of Roofing Felt Papers
Traditional organic felt paper relies on natural fibers but typically includes non-recyclable asphalt, affecting disposal. Synthetic felts, generally made from plastics, offer longer service life which minimizes replacement frequency and waste generation. Some manufacturers utilize recycled plastics for synthetic felt production, contributing to circular economy efforts within the roofing industry. Proper disposal following local regulations helps mitigate environmental impact.
Frequently Asked Questions About Roofing Felt Paper
Can I install roofing felt paper myself?
Yes, homeowners with proper tools and safety measures can install felt paper; however, professional installation ensures correct application and optimal protection.
Is synthetic felt better than organic felt?
Synthetic felt shows greater durability, water resistance, and ease of installation. It is usually preferred for quality roofing systems but costs more upfront.
How long does roofing felt last?
Organic felt lasts approximately 5-10 years, while synthetic felt can last 20 years or more when protected by shingles.
Does roofing felt affect shingle warranty?
Improper or incompatible felt paper may void roofing material warranties; always verify with the shingle manufacturer’s requirements.
What weight of felt paper should I choose?
For most residential roofs, 30 lb felt or equivalent synthetic felt underlayment is recommended for enhanced protection.