Can You Put Tar Paper Over Shingles

The short answer is generally no. Tar paper, or traditional asphalt roofing felt, is not designed to be laid directly over existing shingles as a final surface. While some homeowners consider a roof overlay, most roofing pros recommend removing old shingles and installing a proper underlayment before re-roofing. This article explains why, what to do instead, and how to approach the project safely and in code compliance.

Why Tar Paper Over Shingles Is Not Recommended

Tar paper serves as an underlayment in a roof system, not as the visible surface. Placing tar paper directly over shingles creates moisture-trapping opportunities, reduces airflow, and can compromise roof longevity. The existing shingle surface is irregular and may have debris, nails, or damage that prevents a smooth, watertight layer beneath new roofing materials. Tar paper is also prone to deterioration under heat and UV exposure if left exposed, which can lead to premature failure.

Better Alternatives To Overlapping Tar Paper On Shingles

There are two primary avenues when upgrading or repairing a roof: remove the old shingles and install new underlayment, or perform a compliant overlay with appropriate materials. The right choice depends on roof condition, codes, and manufacturer requirements.

• Full Roof Replacement (Recommended in Most Cases) Remove existing shingles, inspect the roof deck for damage, repair as needed, install a modern underlayment, and apply new shingles. This approach ensures a clean, watertight surface and supports warranty requirements.
• Roof Overlay Without Tar Paper If local codes permit a re-roof with an overlay, do not place tar paper over shingles. Instead, install a high-quality underlayment (preferably synthetic) over a prepared deck after removing or adequately addressing existing shingles as required by code and the underlayment manufacturer.
• Use Modern Underlayment On Deck Regardless of replacement or overlay, modern underlayment (often synthetic) provides superior protection against moisture, tears, and punctures compared with traditional tar paper.

What To Use Instead Of Tar Paper

Modern roofing uses advanced underlayment that outperforms tar paper. The preferred options include:

• Synthetic Roof Underlayment A durable, lightweight layer that resists tearing, remains stable in heat, and provides reliable moisture protection beneath shingles.
• Ice and Water Shield A self-adhering membrane installed in eaves and around roof penetrations to prevent water intrusion from ice damming and wind-driven rain.
• Manufacturer-Approved Materials Always follow the shingle manufacturer’s installation instructions and recommended underlayment products to maintain warranty validity.

Preparing For A Safe And Proper Roof Upgrade

Preparation is key to a successful roof upgrade. Follow these steps to ensure a durable result:

• Inspect The Roof Deck Check for damaged sheathing, rot, or mold. Replace or repair as needed before applying any underlayment or shingles.
• Clear The Surface Remove loose debris, nails, and protrusions. A clean deck prevents punctures and ensures uniform underlayment adhesion.
• Address Ventilation Ensure adequate attic ventilation to prevent heat buildup and reduce moisture, which extends roof life.
• Follow Codes And Warranties Verify local building codes permit overlays and observe underlayment and shingle warranty requirements.
• Plan For Proper Drainage Maintain proper slope, eave flashing, and access to gutters to prevent water pooling around the roofline.

Installation Steps If Re-Roofing (Not Tar Paper On Shingles)

When performing a re-roof, professionals typically follow these steps to ensure a durable result without tar paper on top of shingles:

• Remove Old Shingles Strip down to the roof deck, inspect, and repair any damage.
• Install Underlayment Roll out synthetic underlayment or peel-and-stick membrane, securing it per manufacturer instructions and ensuring seamless overlaps.
• Add Ice and Water Shield Where Required Place at eaves, valleys, and penetrations to improve water resistance in vulnerable areas.
• Install New Shingles Follow the manufacturer’s pattern for starter courses, nailing, and alignment to achieve a uniform, wind-resistant surface.
• Seal And Inspect Ensure flashing is properly installed around chimneys, vents, and transitions, and confirm there are no gaps or loose bindings.

Common Myths And Clarifications

Myth: Tar paper is enough as a top layer on a roof. Reality: Tar paper is not a long-term waterproof surface and should be beneath final roofing materials, not exposed as the top layer.

Myth: An overlay with tar paper can save money. Reality: While overlays can save labor upfront, improper materials or damage can cause higher repair costs and warranty issues later.

Safety And Professional Guidance

Roof work is hazardous. The safest approach is to hire licensed roofing professionals who follow code requirements and manufacturer recommendations. They will determine whether an overlay is permissible in your area and select appropriate underlayment materials to suit your climate and roof design.

Frequently Asked Questions

1. Can tar paper be used as a temporary roof covering? It is not recommended as a long-term solution; tar paper degrades under sun exposure and provides poor wind resistance.
2. Is it possible to install new shingles directly over old ones? In many cases, yes, but the roof must be structurally sound, and the manufacturer may have restrictions. An underlayment should still be installed according to code and specs.
3. Will reroofing with an overlay affect warranties? Yes. Overlays and improper underlayment can void or limit manufacturer warranties. Always follow guidance from the shingle manufacturer and local codes.

Key takeaway: Do not install tar paper as a top layer over existing shingles. Use modern underlayment beneath new roofing materials, and consider professional evaluation to determine the best approach for your roof’s condition and local regulations.