Roll Roofing Over Shingles: Risks, Problems, and Better Alternatives

Installing roll roofing over existing asphalt shingles is generally not recommended as a long-term solution. While it may serve as a temporary cover for damaged shingles, this approach creates several significant issues:

Key Risks

• Poor Ventilation: Traps moisture between layers, leading to rot, mold, and premature deck deterioration.
• Excess Weight: Adds structural load that the roof framing may not be designed to support.
• Adhesion Failure: Roll roofing often fails to bond properly to the granular shingle surface, causing curling, lifting, and leaks.
• Uneven Surface: The underlying shingle texture telegraphs through, creating an unattractive, wavy appearance.
• Code Violations: Many local building codes prohibit installing new roofing over more than one existing layer.

Best Practice

The proper repair is to remove damaged shingles, inspect and repair the deck, then install new underlayment and shingles. This ensures a durable, code-compliant roof with full warranty coverage.