Roll Roofing Tar Paper: A Practical Guide

Roll roofing tar paper is a lightweight, asphalt-saturated paper used as a weather-resistant underlayment for roll roofing systems. It provides a protective layer between the roof decking and the shingles or metal, helping to resist moisture, UV exposure, and wear during installation. This guide explains what tar paper is, the materials involved, when to use it, how to install it, common issues, and maintenance tips. It focuses on practical concerns for homeowners and builders in the United States, with emphasis on performance, durability, and cost considerations.

What Is Roll Roofing Tar Paper

Roll roofing tar paper is an asphalt-impregnated, felt-like material designed for use as an underlayment beneath roll roofing. It comes in rolls with widths commonly ranging from 24 to 36 inches and thicknesses that balance flexibility and puncture resistance. The product acts as a secondary moisture barrier, catching minor leaks and protecting the roof decking during and after installation. Tar paper is less expensive than more advanced synthetic underlayments, making it a popular choice for small repairs, sheds, and certain roof configurations.

Materials And Types

Tar paper for roll roofing typically uses a fiberglass or organic felts base with asphalt saturation. Key variations include:

• Asphalt-Saturated Felt: The traditional choice, offering good moisture resistance but limited performance in extreme temperatures.
• Fiberglass-Faced: Lighter and more resistant to tears; often used in newer installations.
• Self-Sealing Underlayment: Some tar papers include a self-sealing tar edge to help seal around nails, improving leak resistance.
• Reinforced Underlayment: Adds weave or scrim to improve tensile strength and puncture resistance for exposed edges.

When selecting tar paper, consider climate, roof pitch, expected foot traffic during installation, and compatibility with the chosen roll roofing material. Adherence to local building codes ensures proper performance and warranty compliance.

When To Use Roll Roofing Tar Paper

Tar paper is most appropriate in scenarios such as:

• Low-slope or shed-style roofs where roll roofing is common and a budget-friendly underlayment is desirable.
• Repairs or retrofits where replacing the full underlayment is impractical or cost-prohibitive.
• Temporary or short-term roofing projects where a quick, easy installation is prioritized.
• Regions where roll roofing materials and tar paper are specified by local codes for certain structures like outbuildings or accessory structures.

It is important to verify compatibility with the chosen roll roofing system and to follow manufacturer guidelines for underlayment use, overlaps, and fastener patterns to ensure a watertight assembly.

Installation Overview

Proper installation is essential for performance. A typical approach includes:

• Prepare the roof deck by repairing damaged boards and ensuring a clean, dry surface.
• Unroll tar paper starting at the low edge and align to minimize waste.
• Overlap edges by 2 to 4 inches and stagger joints between adjacent courses to reduce leak paths.
• Secure with roofing nails or staples as recommended by the manufacturer, avoiding over-penetration that could damage the deck.
• In cold weather, warm the underlayment slightly to improve flexibility and reduce tearing.
• Proceed with roll roofing installation atop the tar paper according to the roll roofing manufacturer’s instructions.

Tips for success:

• Maintain clean, dry surfaces during installation to ensure proper adhesion and fastening.
• Check local codes for required nailing patterns and overlaps for tar paper underlayment.
• Inspect rolls for damage before use; replace any torn or water-damaged material.

Common Pitfalls And Troubleshooting

Understanding potential issues helps prevent expensive repairs later. Common problems include:

• Punctures: Sharp edges, nails, or tools can puncture tar paper, creating leakage paths. Use careful handling and protective footwear during installation.
• Improper Overlaps: Inadequate overlaps can allow moisture infiltration at seams. Ensure the recommended overlap width is maintained.
• Incorrect Fastening: Overdriven or under-driven fasteners can compromise the underlayment’s effectiveness and create wind uplift risks.
• Moisture Between Layers: A damp deck at installation time can trap moisture and cause deterioration. Always ensure a dry surface.
• Incompatibility With Roof Materials: Some modern synthetic roll roofing materials may require different underlayment; always follow the manufacturer guidelines.

When issues arise, replace damaged sections promptly and re-secure seams to restore performance. Regular inspections after storms can help identify and address leaks early.

Maintenance And Longevity

Proper maintenance extends the life of roll roofing systems using tar paper underlayment. Key practices include:

• Schedule periodic roof inspections, especially after severe weather, to identify lifted edges, punctures, or loosened fasteners.
• Keep debris away from the roof edge to avoid abrasion and moisture retention that can accelerate wear.
• Replace damaged tar paper sections rather than patching extensively, preserving the underlayment’s protective role.
• Coordinate maintenance with the life expectancy of the roll roofing material; tar paper typically serves as a secondary barrier and may need replacement if the roof is re-roofed.

Cost considerations remain an important factor. Tar paper is generally one of the more affordable underlayment options, but installation labor and the chosen roll roofing system influence total project costs. For many small structures, tar paper provides a balance of protection, ease of use, and budget suitability, especially when combined with standard asphalt roll roofing.