Flashing plays a critical role in keeping your roof watertight by directing water away from vulnerable areas like chimneys, skylights, valleys, and walls. While the metal itself—often galvanized steel, aluminum, or copper—is designed to resist the elements, painted flashing is especially vulnerable over time. When the paint coating begins to break down, it exposes the underlying metal to moisture and air, increasing the risk of rust and long-term deterioration.
Why Flashing Is Painted
Paint serves both aesthetic and protective functions for roof flashing:
Protective barrier: Prevents moisture from reaching the metal surface.
UV resistance: Reduces degradation from sun exposure.
Corrosion resistance: Helps delay rust formation, especially in galvanized steel.
Visual cohesion: Matches flashing to roofing or trim color for a more polished look.
When this protective layer fails, rust can form—sometimes going unnoticed until it's caused damage beneath the surface.
Causes of Paint Breakdown on Flashing
Age and Weathering
Over time, UV rays, rain, wind, and temperature swings cause paint to crack, peel, and fade.
Improper Surface Preparation
If flashing wasn’t properly cleaned or primed before painting, the finish won’t adhere well and may fail prematurely.
Incompatible Paint Type
Using the wrong type of paint (e.g., interior or non-metal-specific) can lead to poor performance outdoors.
Physical Damage
Hail, debris, or maintenance work can chip or scratch the paint, exposing bare metal.
Prolonged Moisture Contact
Leaves, snow, or pooling water can sit against flashing and break down paint faster.
Risks of Rusting Flashing
Water Intrusion: Rusted flashing can develop pinholes or separate at joints, allowing water to seep into the roof structure.
Structural Damage: Persistent leaks can lead to rot, mold, or damaged framing.
Accelerated Roof Deterioration: The areas around rusted flashing may age faster or require early replacement.
Increased Repair Costs: Delaying action allows minor rust to spread into a more expensive problem.
Signs of Paint Breakdown and Rust Risk
Peeling, flaking, or chalky paint on metal flashing
Orange or brown discoloration at seams or edges
Surface bubbling or blistering
Visible rust spots or corrosion streaks on roofing or siding
Loose flashing due to weakened fasteners from rust
How to Address and Prevent Flashing Paint Breakdown
1. Regular Inspection
Include flashing in your annual roof inspection—look closely around chimneys, skylights, dormers, and roof-wall intersections.
2. Touch-Up Painting
Light surface damage can be sanded, primed, and repainted using a rust-inhibiting metal paint.
3. Rust Removal
If rust is visible but hasn’t penetrated deeply, use a wire brush or rust converter before priming and repainting.
4. Replace Severely Damaged Flashing
When rust has eaten through the metal or compromised seams, replacement is necessary to restore waterproofing.
5. Use High-Quality Paint and Materials
Always use metal-specific, exterior-grade paint with UV protection and rust inhibitors.
For replacements, consider corrosion-resistant materials like aluminum or copper, which don’t rust.
6. Ensure Proper Drainage
Avoid water pooling near flashing by keeping gutters and valleys clear and ensuring proper roof slope.
When to Call a Professional
If rust is widespread or you're unsure of the flashing's condition beneath the paint, a roofing contractor can evaluate and determine whether repair or full replacement is needed. They can also ensure that any repainting is done properly and will hold up long-term.
Final Thoughts
Paint breakdown on flashing may seem like a minor cosmetic issue, but it's often the first sign of deeper problems. Staying on top of small repairs, especially in harsh or coastal environments, can prevent rust from compromising the integrity of your roof. Regular inspection, maintenance, and the use of quality materials will keep your flashing—and your roof—performing at their best.