“Tar paper” is a common name for asphalt-saturated roofing felt, an underlayment installed beneath shingles or other roof coverings. A tear or loose edge can allow water to reach the roof deck, but the right repair depends on where the damage is and what covers it. This guide explains how to assess tar paper roof damage, make a limited repair when conditions are suitable, and identify problems that call for professional help.
What Tar Paper Does on a Roof
Roofing felt is a water-shedding layer installed over roof sheathing and beneath the finished roof covering. It can help protect the deck from moisture during construction and from water that gets past shingles, tile, or another covering. It is not a substitute for properly installed shingles, flashing, or a roof drainage system.
Traditional roofing felt is made from a fibrous base saturated with asphalt. Modern underlayments may instead use synthetic materials or self-adhering membranes. Although these products serve related purposes, they are not all repaired with the same materials or methods. The product label, roof system, and manufacturer’s installation instructions matter.
The phrase “tar paper” can also be used loosely for roofing materials in built-up or low-slope roof assemblies. Those systems may have several layers and require specialized repair. A patch suitable for exposed felt beneath shingles may not be appropriate for a built-up roof surface.
Signs That Roofing Felt May Be Damaged
Underlayment is usually hidden, so a leak does not automatically mean the tar paper is torn. Water can enter at a roof penetration, damaged flashing, a failed shingle, an ice dam, or a valley and travel along the deck before appearing indoors. Look for the source rather than assuming the first visible stain is directly below the defect.
- Visible tears or holes: Felt may be exposed during a roofing project or where shingles have slipped or blown off.
- Wrinkles, bubbles, or loose laps: These can indicate poor installation, movement, or exposure to wind and moisture.
- Water stains or damp sheathing: Interior staining, attic moisture, or soft roof decking may point to a roof leak.
- Exposed or deteriorated underlayment: Sunlight and weather can damage felt that is no longer protected by the roof covering.
- Corrosion or pulled fasteners: Rusted, loose, or improperly placed nails can compromise laps and create paths for water.
An attic inspection can help identify wet areas, but it does not replace a roof inspection. A qualified roofer can trace water paths and determine whether the problem involves underlayment, shingles, flashing, decking, or more than one component.
Can Tar Paper Be Repaired Without Replacing the Roof?
Yes, a small, accessible tear may be repairable, but only if the surrounding roof assembly is sound. If shingles cover the felt, the roofer generally needs to lift or remove enough shingles to reach the damage, patch the underlayment, and reinstall or replace the roof covering. Smearing roofing cement over the top of shingles is not a reliable repair for a hidden underlayment tear.
A patch is unlikely to solve the problem if the deck is rotten, the felt is brittle or extensively torn, water has soaked insulation, or the leak comes from failed flashing. Repeated patching can hide deterioration while damage continues beneath the surface. In these cases, the affected section may need to be opened and rebuilt.
On a low-slope or built-up roof, repair methods depend on the membrane, the number of layers, and the existing materials. Applying asphalt cement or a peel-and-stick product without confirming compatibility can trap moisture, damage the roof, or interfere with a future repair. A roofing contractor familiar with that specific roof type should assess it.
Materials and Tools for a Limited Repair
The correct materials depend on the roof covering and the underlayment. For a typical asphalt-shingle roof, a repair may involve replacement roofing felt or a compatible underlayment, roofing nails or other approved fasteners, replacement shingles, and roofing cement where the shingle manufacturer or repair detail calls for it.
Some repairs use a self-adhering membrane as a localized patch, but it must be approved for the application and compatible with the roof assembly. Do not assume that any roll of “tar paper,” plastic sheet, or roofing tape is an appropriate substitute. Follow product instructions and applicable local building requirements.
Common tools include a flat pry bar, hammer, utility knife, measuring tape, and a sturdy ladder. Personal protective equipment may include gloves and eye protection. Roof work carries a serious fall risk; tools do not make a steep, wet, icy, or windy roof safe to access.
How a Small Tear Is Typically Repaired
The steps below describe a general repair approach for a small area beneath asphalt shingles. The exact method varies by shingle and underlayment manufacturer, roof pitch, and local code. If the roof is steep, high, fragile, or difficult to access, the repair should be left to a professional.
- Find and assess the damage. Check the attic and the roof area for the likely entry point. Confirm whether the felt is actually damaged and inspect the sheathing and nearby flashing for signs of rot or water intrusion.
- Wait for suitable weather. The roof surface should be dry, and conditions should be calm. Wet felt, rain, frost, and strong winds make both the repair and roof access unsafe.
- Expose the affected area carefully. If shingles cover the tear, a roofer may loosen or remove shingles around it to reach sound underlayment. Avoid breaking shingles or damaging nearby flashing.
- Remove compromised material if needed. Cut away only loose or badly damaged felt. If the wood deck is soft, stained through, or decayed, the repair needs to address the decking rather than cover it.
- Install a compatible patch. The patch should extend beyond the damaged area and be placed so water sheds over the lower layer. Follow the underlayment maker’s required overlap and fastening pattern; avoid creating an upward-facing edge that can catch water.
- Restore the roof covering. Reinstall or replace shingles and secure them according to their instructions. Apply roofing cement only where specified, since excessive sealant can interfere with shingle performance and make later repairs harder.
- Check the repair. Inspect the work for lifted edges, exposed fasteners, damaged shingles, and clear drainage paths. Monitor the area after rain and check the attic for continuing moisture.
Underlayment installation details are not interchangeable. For example, a patch’s placement and fastening may differ between felt, synthetic underlayment, and a self-adhering membrane. Manufacturer instructions and local code take precedence over a generic repair description.
Common Tar Paper Roof Repair Mistakes
- Using roofing cement as the entire repair: Cement may have a role in certain details, but a surface smear does not properly replace torn underlayment beneath shingles.
- Covering wet or rotted materials: A patch over damp insulation or deteriorated sheathing can conceal ongoing damage and slow drying.
- Mixing incompatible products: Adhesives and membranes can react poorly or fail to bond when used outside their intended roof system.
- Leaving exposed felt in place: Underlayment is generally designed to be covered by the finished roof, not to serve as a permanent exposed roof surface.
- Ignoring the entry point: Water may be coming from flashing, a vent, a valley, or a roof edge rather than the visible tear.
- Working in unsafe conditions: Rain, ice, loose roofing, steep slopes, and high winds increase fall risk. A temporary repair is not worth a serious injury.
When to Call a Roofing Professional
Professional assessment is especially important when the roof is steep or more than one story high, the damaged area is large, the decking feels soft, or the leak returns after a previous repair. A roofer should also inspect suspected damage around chimneys, skylights, plumbing vents, valleys, and roof-to-wall transitions, where several materials meet.
Contact a contractor promptly if water is actively entering the home, ceiling material is sagging, or water is near electrical fixtures. Keep people away from sagging ceilings, and do not touch wet electrical equipment. If safe, move belongings and contain drips without climbing onto the roof. For immediate danger, contact emergency services or the appropriate utility provider.
After a storm, photograph visible damage from the ground and document interior leaks. Avoid making permanent repairs before documenting conditions if an insurance claim may be involved. For emergency mitigation, prioritize safety and keep receipts; policy requirements vary, so the homeowner should contact the insurer and review the policy.
Repair, Replacement, and Cost Factors
There is no dependable single price for tar paper roof repair. Cost depends on roof height and pitch, access, region, roofing material, extent of water damage, and whether shingles, flashing, or decking must be replaced. A small repair during a larger roofing project may cost less than a stand-alone visit that requires setup and diagnosis.
When comparing estimates, ask what caused the leak, which layers will be opened, what products will be installed, whether damaged sheathing or insulation is included, and how the completed work will be checked. A written estimate should distinguish the repair itself from optional improvements and explain any limits on warranties.
If felt is deteriorated across a broad area, or the roof covering is near the end of its service life, replacing a small patch may be temporary. A roofer can compare the cost and expected durability of a localized repair with replacement of the affected roof section or the complete roof system.
How to Reduce the Risk of Future Underlayment Damage
- Have the roof inspected after major storms and during routine home maintenance, especially if shingles are missing or displaced.
- Keep gutters and downspouts clear so water does not back up at the roof edge.
- Trim branches that scrape the roof or drop debris into valleys and gutters.
- Address damaged flashing and loose roof coverings before water reaches the underlayment.
- During reroofing, confirm that the contractor uses underlayment suitable for the roof covering, climate, and local code.
- Keep records of repairs, product information, and roof inspections to help identify recurring problems.
In cold climates, ice dams can force water beneath roof coverings, while heavy rain and wind can expose weaknesses in other regions. Proper attic ventilation and insulation may help reduce ice-dam conditions, but they do not replace sound flashing, underlayment, and roof drainage.
Reliable References for Roof Repair Decisions
For product-specific instructions, consult the roofing-underlayment and shingle manufacturer’s published installation guidance. The National Roofing Contractors Association provides roofing-industry resources, while the Occupational Safety and Health Administration’s fall-protection guidance explains why roof access requires serious safety precautions. Local building departments can clarify code requirements for repairs and reroofing.
Because roofing systems vary, online guidance should be treated as general information rather than a substitute for an inspection. A repair is most reliable when it identifies the actual leak source, uses compatible materials, restores every affected layer, and leaves the roof safe and watertight.