Rolls of roofing felt are a foundational building material used to protect roofs from moisture, temperature fluctuations, and weathering during and after installation. This guide explains the types, benefits, installation considerations, and maintenance practices homeowners and contractors should know. It covers choosing the right roofing felt rolls, understanding lifespans, and best practices for storage and handling to maximize durability and performance. By understanding the nuances of roofing felt, readers can make informed purchasing decisions and optimize roof longevity.
What Roofing Felt Rolls Are And Why They Matter
Roofing felt rolls are sheets of asphalt- or composite-based material used as underlayment, installation vapor barriers, and temporary roof protection. They come in various weights and textures, typically measured in “pounds per 100 square feet” (per 100 ft²) or by weight per roll. The primary role is to provide a secondary layer of protection against leaks, wind-driven rain, and ice dam formation. For many shingle and membrane roofs, roofing felt is a standard step in the roof assembly.
Common Types Of Roofing Felt Rolls
There are several roofing felt options, each with distinct properties and best-use scenarios.
- Building Paper (Untreated Felt): Lightweight, economical, and used as a moisture barrier in older or simple roof assemblies. It offers basic protection but limited durability in harsh climates.
- Important Asphalt-Saturated Felt: Treated with asphalt to resist moisture and provide added durability. Suitable for many residential applications and commonly used under shingles.
- Felt With Asphalt Saturation And Mineral Granules: Combines a felt base with mineral granules for UV protection and improved tear resistance. Often used as a secondary layer or in composite roofing systems.
- Self-Adhering/Self-Únrolling Roofing Underlayment: Typically a peel-and-stick option with a release film, offering high wind uplift resistance and easier installation on steep slopes or retrofits.
Materials And Performance: What Impacts Durability
Rolls of roofing felt come from asphalt-impregnated organic fibers or fiberglass-reinforced substrates. The substrate material influences tear strength, puncture resistance, and overall lifespan. Heavier felt (e.g., 30-lb or 40-lb) generally offers greater durability, tear resistance, and long-term performance in areas with heavy precipitation or wind. The asphalt content affects waterproofing capabilities and flexibility in cold weather. In colder climates, higher asphalt saturation helps maintain adhesion and prevents cracking.
Applications And Best Uses
Roofing felt rolls are versatile in both new construction and roofing renovations. They are commonly used as:
- Temporary weather protection during construction and repairs
- Underlayment beneath shingles, tiles, or metal roofing
- Vapor barriers to reduce interior condensation in certain roof assemblies
Selection should align with local climate, roof pitch, and the chosen final roof covering. Self-adhering underlayment tends to be favored on roofs with steep slopes or in regions prone to wind-driven rain.
Installation Essentials
Proper installation of roofing felt rolls ensures the intended protective function. Key steps include:
- Surface Preparation: Ensure the roof deck is clean, dry, and structurally sound before application.
- Overlap And Seams: Standard practice is a minimum 2-inch (5 cm) overlap along horizontal seams and 6 inches (15 cm) at overlaps with adjacent courses. For self-adhering underlayments, follow manufacturer guidelines for bonding and nail placement.
- Nail Placement: Use corrosion-resistant nails and place them along the joints as specified. Avoid over-nailing to prevent deck damage.
- Ventilation And Weather: Install during favorable weather when possible. Rain or moisture can compromise adhesion and performance.
- Compatibility: Confirm compatibility with the final roofing material, such as asphalt shingles, clay tiles, or metal panels.
Storage And Handling
Proper storage extends the life of roofing felt rolls. Store in a dry, shaded area off the ground, protected from direct sunlight. Keep rolls flat and stacked to avoid deformation. If rolls become damp, allow them to dry completely before installation to prevent mold and reduced performance. Transport rolls on equipment that minimizes crushing or tearing the material.
Standards, Certifications, And Health Considerations
Quality roofing felt should meet applicable building codes and industry standards. Look for products that comply with local roofing underlayment regulations and certifications from recognized bodies. While roofing felt is generally low-risk, avoid prolonged exposure to solvents or fumes during handling and ensure proper ventilation when applying asphalt-saturated products.
Cost And Availability
Cost varies by weight, material, and brand. In general, heavier felt rolls cost more per roll but offer greater durability in demanding climates. Availability is broad in home improvement stores, roofing suppliers, and online retailers. When budgeting, include potential additional materials such as sealants, fasteners, and edge detailing required for complete underlayment installation.
Environmental Considerations And Sustainability
Some roofing felt products are designed for lower environmental impact, including recycled content substrates and reduced volatile organic compound (VOC) emissions during manufacturing. End-of-life recycling options and local disposal guidelines should be considered. Homeowners may prefer products with longer lifespans to minimize replacement frequency and waste.
Choosing The Right Rolls Of Roofing Felt For A Project
Choosing the right roofing felt roll depends on climate, roof type, and budget. Consider:
- Climate: Colder climates benefit from higher asphalt saturation for flexibility and adhesion in low temperatures.
- Roof Slope: Steeper slopes may benefit from self-adhering underlayment for wind resistance.
- Final Roofing Material: Ensure compatibility with shingles, tile, or metal roofing chosen for the project.
- Durability Needs: For long-term protection with heavy weather exposure, select higher-weight rolls.
In practice, a balanced approach combines reliable underlayment performance with ease of installation. Contractors often specify a specific weight range (for example, 15- to 30-lb felt) tailored to local building codes and climate data. Homeowners should verify product warranties and installation requirements with the supplier or contractor before purchasing.