Counter flashing is a key element in a roofing system, designed to work alongside other types of flashing to protect the joints between a roof and vertical structures like walls or chimneys. Its role is to ensure a watertight seal, preventing water from penetrating vulnerable areas.
What is Counter Flashing?
Counter flashing is a strip of metal or other durable material installed over base or step flashing. It is typically embedded into the mortar joints of a chimney or secured to a wall, overlapping the lower layers of flashing. This overlapping design creates a secondary barrier that directs water away from the roof’s surface.
Key Features of Counter Flashing
- Material: Commonly made from galvanized steel, aluminum, or copper due to their durability and resistance to weather.
- Position: Installed above base or step flashing to provide additional protection against water infiltration.
- Integration: Often embedded into masonry or securely fastened to vertical structures for a long-lasting seal.
The Importance of Counter Flashing
Counter flashing plays a crucial role in protecting areas of the roof where water could seep in, particularly:
- Around Chimneys: Provides a secure barrier between the chimney and the roof surface, working with base and step flashing to ensure full coverage.
- At Roof-Wall Intersections: Prevents water from entering the junction where the roof meets a vertical wall.
- Over Openings: Protects vent pipes or other penetrations that require additional sealing.
Common Problems with Counter Flashing
- Loose or Detached Flashing: Improper installation or shifting of building materials can cause the flashing to come loose.
- Deteriorated Mortar Joints: For flashing embedded in masonry, cracked or missing mortar can compromise its effectiveness.
- Rust or Corrosion: Over time, exposure to the elements can degrade the metal, reducing its ability to repel water.
- Sealant Failure: Sealants used alongside flashing may crack or deteriorate, creating gaps.
Maintenance and Repair Tips
- Inspect Regularly: Check for signs of wear, especially after storms or heavy weather.
- Reapply Sealant: Replace dried or cracked sealant to maintain a watertight connection.
- Treat Rust: Clean and treat rusted areas to extend the lifespan of metal flashing.
- Repair Mortar Joints: For chimney installations, ensure mortar is intact to keep flashing securely embedded.
- Professional Repairs: Complex issues like resetting flashing or repairing masonry should be addressed by professionals to ensure proper sealing.
Proper Installation of Counter Flashing
For counter flashing to perform effectively, it must be installed with precision. Common steps include:
- Embedding into Masonry: Cutting a small groove into the chimney or wall to fit the flashing securely.
- Overlapping Base Flashing: Ensuring counter flashing overlaps and integrates with base or step flashing to form a continuous barrier.
- Using Durable Materials: Selecting materials resistant to corrosion and wear to enhance longevity.
Counter flashing is a vital component in protecting a roofing system from water damage. By understanding its function, recognizing potential issues, and keeping up with maintenance, homeowners and professionals can ensure long-term durability and performance.