Tar paper, or roofing felt, provides a moisture barrier and a stable nailing base under shingles or other roofing materials. Proper application helps extend roof life, resist moisture intrusion, and improve overall durability. This guide covers essential steps, tools, and best practices for applying tar paper efficiently and safely.
Materials And Tools
Having the right supplies ensures a smooth installation and reduces the need for rework. The following items are commonly used when applying tar paper:
- Tar paper rolls (asphalt-saturated roofing felt) in the appropriate weight for the climate and roof deck.
- Roofing nails or staples with a hammer gun, sized for the tar paper and deck.
- Nail starter strip or a chalk line for alignment.
- Tin snips or a utility knife for trimming.
- Roofing cement for edge sealing and starter strips.
- Chalk line for straight, evenly spaced rows.
- Weatherproof sealant for seams and flashing corners.
- Ladder and fall protection and appropriate PPE, including gloves and eye protection.
Preparing The Surface
Quality results start with a clean, dry roof deck. The surface should be free of debris, dust, and protruding nails. Inspect for damaged or warped boards and replace as needed. If moisture is present, wait until the deck is dry before installation. Nail spacing guidelines should be followed to avoid creasing or tearing the tar paper during application.
Installing The First Layer
The initial layer establishes alignment and base protection. Begin at the bottom edge of the roof and work upward. Unroll the tar paper to minimize wrinkles and repositioning. Align the edge with the eave line and ensure an even overhang beyond the fascia. The standard overlap for adjacent courses is typically 2 inches across the deck, with 4 to 6 inches at corners or hips, depending on local codes. Secure with nails along the upper edge of each strip, spacing nails approximately 6 to 8 inches apart.
Overlapping And Fastening
Proper overlap and fastening prevent water intrusion and wind uplift. Each subsequent strip should overlap the one below by about 2 inches, ensuring a continuous barrier. Fasten every 8 to 12 inches along the joints, particularly near edges and corners. For steeper roofs or windy climates, increase nail frequency or use staples as permitted by manufacturer guidelines. Avoid over-tightening nails, which can cause tears or distortions in the tar paper.
Sealing Seams And Edges
Seams and edges are critical moisture points. Apply roofing cement along the upper seam after nailing if required by local practice. For exposed edges, use a sealant bead along the entire length to prevent wind-driven moisture from lifting the paper. At roof valleys, hips, and around penetrations, ensure extra overlap and secure with compatible sealants. Check manufacturer recommendations for seam adhesives or tapes designed for asphalt-saturated felt.
Weather And Temperature Considerations
Tar paper application performs best in moderate temperatures, typically between 50°F and 85°F. Extremely cold conditions can make the material stiff, difficult to handle, and prone to tearing. High heat can soften the felt and affect adhesion. If weather shifts, pause work during rain or high humidity to prevent moisture entrapment. In urgent repairs, use temporary measures and schedule full installation when conditions improve.
Quality Control And Common Issues
Inspect the installed rows for wrinkles, gaps, or misalignment. Smooth out any wrinkles before nailing, and correct loose edges promptly. Common issues include:
- Wrinkles caused by improper tension; re-roll and re-seat the section.
- Gaps at seams or corners; reseal with additional cement or tape per manufacturer guidance.
- Lifted edges due to wind; add extra fasteners and sealant to secure.
- Moisture entrapment from installing over damp deck; ensure dryness before applying.
Maintenance And Longevity
Tar paper should be inspected during routine roof maintenance. Look for curling, tearing, or moisture staining. If the felt shows signs of deterioration beyond minor wear, consider replacing affected sections or reinstalling a fresh layer when re-roofing. Regular inspections after severe weather help detect problems early and prevent leaks.
Safety Considerations
Working on a roof involves fall risks. Use proper fall protection, secure ladders, and wear non-slip footwear. Handle sharp tools with care and store materials securely to prevent wind hazards. Follow local codes for fall protection and material handling. When in doubt, consult a professional roofer for complex installations or high-risk projects.
Quick Reference: Overlap And Fastening Guidelines
| Aspect | Recommendation |
|---|---|
| First layer overlap | 2 inches over the deck edge |
| Adjacent course overlap | 2 inches |
| Edge fasteners | 6–8 inches apart along edges |
| Corner/seam sealing | Apply sealant or tape per manufacturer |
| Weather window | Temperatures 50–85°F preferred |