Flashing a chimney on copper roofing involves creating a watertight seal where the chimney meets the roof, protecting against leaks caused by water infiltration. Copper step flashing consists of individual L-shaped pieces placed in a stair-step pattern along the sides of the chimney, integrated with the roof shingles or copper panels to direct water away. Counter flashing is installed on the chimney itself, typically cleated or crimped over the step flashing, covering the upper edge to prevent water from seeping behind it. This double-layer system ensures durability and waterproofing, especially important with copper’s thermal expansion properties. Flashing can fail due to poor installation, corrosion (though copper is quite resistant), or movement of the chimney or roof. White staining or greenish patina around the chimney, visible water stains inside your attic, or drips after heavy rain can be signs of flashing issues.
To safely inspect your chimney flashing, start by looking on the roof for cracked, loose, or missing pieces of flashing or sealant. Avoid walking on copper roofing if possible—use binoculars or a mirror on an extension pole to check from a safe distance. Small gaps, rust stains, or curled edges indicate the need for repair. Since copper flashing requires precise handling and is often soldered or mechanically joined for integrity, many homeowners should call a professional roofer if any damage is suspected. When speaking with a contractor, ask if they will solder the flashing joints or rely solely on sealants and if their work maintains the integrity of your copper panels and roofing warranty. Additionally, inquire about how they plan to allow for copper’s thermal expansion to prevent future cracking or separation.