Can You Staple Roofing Felt: A Practical Guide

Roofing felt, also known as tar paper or underlayment, plays a crucial role in protecting a roof deck from moisture and advancing roof assembly integrity. The method of fastening felt—whether with staples, nails, or adhesive—depends on the felt type, climate, roof pitch, and local building codes. This guide examines whether stapling is appropriate, the best fasteners to use, how to install it correctly, and common pitfalls to avoid for a durable, weather-tight roof.

What Is Roofing Felt and Why It Matters

Roofing felt is a layer installed over the roof deck before shingles or other roofing materials. It provides a secondary barrier against wind-driven rain, helps seal nail penetrations, and improves the overall longevity of the roof system. There are two main types of felt used in residential roofing: organic felt (historically made from paper products) and fiberglass-reinforced asphalt-saturated felt. Both can vary in thickness and weight, which influences fastening methods and installation practices. When selecting felt, homeowners should consider climate, roof pitch, and local code requirements to ensure proper performance.

Staples vs. Nails: Which Fastener Is Best?

Fastening roofing felt generally involves nails or staples designed for outdoor exposure. Staples are often used with plywood or OSB decks in some regions when lighter fasteners are permissible and the felt is compatible with staple heads. However, most manufacturers and roofing codes favor galvanized nails or plastic cap nails for longer durability and a more secure hold in varying weather. Staples can work for certain applications, but they may loosen or tear through the felt under wind, temperature fluctuations, or foot traffic on the roof, especially with heavy shingles above. The key is to consult the felt manufacturer’s installation instructions and local building codes before deciding on stapling as the primary method.

Best Staples For Roofing Felt

If staples are permitted by the manufacturer or required by local practice, use cold-formed, corrosion-resistant staples designed for outdoor exposure. Common choices include galvanized steel or stainless steel staples with a wide crown to distribute load and minimize tearing of the felt. Staples should be sized appropriately for the decking material and felt thickness. For example, a 1/4-inch crown staple with a 1/2 inch to 5/8 inch leg length is typical for asphalt-saturated felt over plywood. Always verify compatibility with the roofing felt material and avoid staples that can bend or shear under load. Proper staple length ensures the staple penetrates the deck sufficiently to resist uplift without tearing the felt.

Installation Techniques If Staples Are Permissible

When stapling is allowed, follow these best practices to maintain a weatherproof seal. Start at the eave and work upward with consistent, evenly spaced fasteners. Use staples every 6 to 8 inches along the edge and every 8 to 12 inches in the field, or as specified by the felt manufacturer. Ensure the staples lie flush with the surface without tearing the felt. Overlap edges by at least 2 inches to prevent wind-driven infiltration. Do not staple across the overlap seams where shingles will cover; instead, maintain an uninterrupted seal beneath the shingle layer. Check for any dents, punctures, or misfires and replace damaged sections promptly. If any staples miss the decking, repair or reseat the felt segment to maintain integrity.

Step-By-Step Installation Guide

Preparation: Inspect the roof deck for smoothness, repair damaged areas, and remove debris. Confirm climate considerations and local code requirements. Material check: Verify felt type, staple size, and the compatibility of fasteners with the deck material. Safety: Use fall protection, ladder stabilizers, and weather-appropriate PPE.

Application: Begin at the drip edge, align the felt squarely, and unroll steadily. Place staples along the eave edge every 6–8 inches, ensuring the crown sits flat and the legs penetrate the deck. Continue across the field with staples every 8–12 inches, maintaining even tension to avoid sagging. Overlap edges by 2 inches, then staple along the overlap to secure seams. Avoid stapling near roof penetrations unless specified by the manufacturer, and maintain a consistent pattern across the entire surface.

Inspection: After installation, scan for loose staples, lifted edges, or misaligned overlaps. Address any issues before shingles are installed. A smooth, continuous surface reduces the risk of moisture infiltration and wind uplift under the final roof covering.

When Staples May Not Be Appropriate

In many modern residential applications, staples are not recommended due to potential durability concerns under extreme weather. Heavy wind uplift, freezing and thawing cycles, and long-term exposure can loosen staples, create gaps, or tear the felt. In such cases, roofing nails or caps, adhesive underlayments, or peel-and-stick membranes are preferred. Some regions require nails with caps to ensure a robust hold, especially on low-slope roofs. Always prioritize the fastestens system specified by the felt manufacturer and local building codes to preserve warranty coverage and structural integrity.

Safety, Codes, And Warranties

Compliance with safety standards and building codes is essential. Use galvanized or stainless-fasteners designed for exterior exposure and avoid any fasteners that could corrode or react with the felt. Adhere to the manufacturer’s installation instructions, as improper methods can void warranties or compromise performance. Local codes may dictate acceptable fastening methods, staple types, and spacing requirements. If in doubt, consult a licensed roofing contractor or building inspector to confirm compliance and ensure the installation meets industry standards.

Common Mistakes To Avoid

• Using staples that are too short or not corrosion-resistant, leading to failure in moisture-rich environments.
• Overlapping seams without proper fastening along the seam line, creating wind uplift risks.
• Penetrating the deck with staples in locations that shingles will cover, causing uneven support surfaces.
• Ignoring manufacturer guidance or local codes, which can void warranties.

Final Considerations For Homeowners

For most homeowners, stapling roofing felt is only appropriate when explicitly allowed by the manufacturer and local building codes. If uncertainty exists, opting for nails or other approved fastening methods ensures a longer-lasting, more reliable underlayment. When in doubt, hire a qualified roofer to ensure correct installation, proper fastener selection, and adherence to safety standards. A well-executed underlayment installation reduces future maintenance needs and contributes to the overall durability of the roof system.