Best Felt Paper for Roofing
The right felt paper or underlayment is a crucial layer in a roofing system, providing a moisture barrier, temporary weather protection, and a surface for shingles to grip. This guide reviews the best felt paper options for American homes, compares traditional asphalt-saturated felt with modern synthetic underlayment, and offers practical guidance for selection, installation, and performance considerations.
What Is Felt Paper For Roofing?
Roofing felt paper, also known as underlayment, is installed between the roof deck and the final shingles or tiles. Its primary roles are to block water intrusion, reduce surface imperfections, and provide a slip-resistant surface during shingle installation. Traditional felt is made by saturating or coating paper with asphalt, creating a durable, tear-resistant barrier. Synthetic underlayment uses polymer films or nonwoven fabrics to achieve higher strength, lighter weight, and improved dry performance. The choice between asphalt-saturated felt and synthetic options depends on climate, roof design, and local building codes.
Types Of Felt Paper And Underlayment
Understanding the main categories helps builders select the best product for longevity and performance. Each type has distinct advantages and limitations.
- Traditional Asphalt-Saturated Felt (15 lb or 30 lb): Durable, cost-effective, and well understood by professionals. Provides good moisture resistance when dry and offers familiar nailing recommendations. It can be heavier and less resistant to tearing in cold weather.
- Manufacturer-Labeled Felt Paper (e.g., 30 lb, 60 lb equivalent ratings): Variations in base weight and asphalt saturation can affect tear strength and nail pull resistance. Higher weight often equates to better durability in demanding climates.
- Synthetic Underlayment (polypropylene or polyethylene-based): Lightweight, tear-resistant, and often more resistant to water absorption. Dries quickly and can offer better slip resistance when dry, but may be more expensive and requires careful fastener selection to avoid damage.
- Frozen/Dry Weather Considerations: In colder climates, some underlayments are designed to resist cracking and tearing when exposed to low temperatures. Consider products with dual-layer protection for enhanced performance.
- arkitectural And Code Compatibility: Local codes may specify minimum underlayment standards (such as water resistance and permeance). Always verify compatibility with the roof system and climate zone.
Choosing The Best Felt Paper For Your Roof
Selecting the right underlayment involves climate, roof pitch, slope, deck type, and the planned roofing material. The following criteria help homeowners and contractors identify optimal products.
- Climate And Exposure: In wet, snowy, or coastal regions, consider higher water resistance and longer exposure limits. Synthetic underlayments often perform better in wet conditions and offer greater longevity.
- Roofing Material Compatibility: Shingles, metal, or tiles may have different fastener recommendations. Some synthetics tolerate longer exposure during installation or provide better compatibility with roof clips.
- Permeability And Vapor Control: A balance between moisture blocking and vapor diffusion is essential to prevent condensation. Many codes require water-impervious layers; in some cases, breathable options are used in combination with proper ventilation.
- UV Exposure And Wind Resistance: Some underlayments are rated for temporary UV exposure during installation. Wind-driven rain resistance is also a consideration for exposed courses during construction.
- Installation And Fastening: Ensure the underlayment works with the chosen nails or staples, and follow the manufacturer’s nailing pattern. Synthetic products may require specific fasteners and spacing to prevent tearing.
- Durability And Tear Resistance: For steep pitches or heavy shingle loads, higher tear resistance minimizes damage during installation and in strong winds.
- Code And Warranty: Look for products with recognized certifications and warranties that match the roof’s expected lifespan. A longer warranty can reflect broader testing and higher performance.
Installation Tips For Felt Paper And Underlayment
Proper installation ensures the underlayment performs as intended. The following steps help achieve a durable, weather-tight roof.
- Surface Preparation: Ensure the roof deck is clean, dry, and free of protrusions that could tear the underlayment. Repair any damaged plywood or sheathing before laying the underlayment.
- Alignment And Overlaps: Install in the direction of the prevailing wind whenever possible. Maintain consistent overlaps—commonly 2 to 4 inches for asphalt felts, and as specified by the manufacturer for synthetics—to prevent water intrusion at seams.
- Nailing Pattern: Use the recommended nail type and spacing. Do not skip fasteners at edges or corners, where uplift risk is higher. For some synthetic underlayments, specialized fasteners or clip systems may be required.
- Ventilation And Condensation Control: Inadequate ventilation can trap moisture, leading to deck rot. Pair underlayment with proper attic ventilation and roof deck moisture barriers as required by code.
- Commitment To Time And Exposure: If work is paused, protect underlayment from prolonged UV exposure or weather. Some products have limited exposure times before shingles must be installed.
- Seasonal Considerations: In cold climates, avoid installing on frozen decks. Warm the area to improve adhesiveness for certain synthetics and reduce the risk of tears during handling.
Brand And Product Comparisons
Below is a comparative overview of commonly used underlayments in the United States, highlighting practical differences for decision-making. The table reflects typical market offerings as of the latest guidelines and may vary by region.
| Product Type | Key Features | Advantages | Limitations | Typical Use |
|---|---|---|---|---|
| Traditional Asphalt-Saturated Felt (15 lb / 30 lb) | Coated paper saturate with asphalt | Cost-effective, easy to find, proven performance | Heavier, less tear-resistant in cold, limited UV resistance | New roofs in moderate climates |
| Coated Asphalt Felt | Additional asphalt coating for water resistance | Improved water protection over standard felt | More expensive, heavier | Regions with higher moisture risk |
| Synthetic Underlayment (Polypropylene/Polyethylene) | Nonwoven fabric or film layers, UV-stable | Lightweight, excellent tear resistance, quick-dry | Higher upfront cost, some brands require specific fasteners | Modern shingle and tile roofs |
| Hybrid Underlayment | Combination of synthetic and asphalt properties | Balanced cost and performance | Variable performance by brand | Versatile installations |
| Ventilated Or Breathable Underlayment | Perforated or permeable layers | Improves moisture management | Not suitable for all climates or roofing materials | Areas with high humidity |
Weather And Climate Considerations
Climate plays a pivotal role in selecting underlayment. In humid regions along the Gulf Coast or Southeastern U.S., high water resistance and quick-drying performance reduce long-term degradation. In colder northern areas, performance in low temperatures, tear resistance, and easier handling during winter months are essential. For coastal properties, salt exposure tolerance and UV stability become more important. Always confirm compatibility with local building codes and roofing material specifications.
Cost And Availability
Underlayment costs vary by material, weight, and brand. Traditional asphalt-saturated felt is typically the most budget-friendly option, while synthetic underlayments offer long-term durability and lighter handling, potentially reducing labor costs. Availability can differ by region; some contractors stock specific brands due to installation experience or warranty coverage. When budgeting, consider the total installed cost, including fasteners, nails, and potential prep work, rather than just the material price.
Durability And Lifespan
Durability depends on material composition, climate exposure, and installation quality. Asphalt felts generally last through the deck’s service life if not exposed to prolonged UV and moisture; synthetic underlayments often provide longer service life and better resistance to tearing. A properly installed underlayment can contribute to a roof system that resists leaks for decades, while improper installation may fail long before the roofing material reaches end-of-life.
Maintenance And Inspection
Underlayment is not a long-term homeowner-maintenance item, but routine inspection after severe weather is prudent. Look for signs of moisture intrusion, cracking, or lifting at eaves and valleys. Damaged areas should be repaired or replaced promptly to prevent subsequent leakage. If a roof is mid-construction or under warranty, document pre-installation and post-installation conditions to support claims in case of issues.