What is flashing?
Flashing is metal (or compatible material) used to waterproof joints and transitions—valleys, chimneys, walls, skylights, and edges.
Where flashing matters most
Chimneys, step flashing at sidewalls, valleys, and penetrations are the top leak zones.
Materials
Galvanized steel, aluminum, copper, and stainless are common—each has pros/cons.
Common flashing mistakes
Improper overlaps, missing counter‑flashing, incorrect sealant use, and poor integration with underlayment.
Signs of flashing problems
Stains near chimneys, leaks after wind-driven rain, rusted metal, or loose pieces.
FAQ
Quick answers to the most common questions.
Can you replace flashing without replacing the roof? +
Sometimes—if shingles are in good condition and the problem is localized. Often chimney/step flashing can be repaired or replaced.
Is sealant enough? +
Sealant is not a long-term solution by itself. Proper metal detailing and overlaps are the real fix.