Flashings

Flashings are components made from metal or other durable materials that are installed at joints in roofs, walls, and around penetrations to prevent water intrusion. They channel water away from joints, transitions, and openings, and they accommodate movement due to temperature changes and building settlement.

Roof flashings include drip edge, apron, step flashing along intersections, valley flashings where two roof planes meet, and chimney or vent flashings that seal around pipes and stacks. Wall flashings protect intersections such as where a roof meets a wall, at window and door openings, and at balcony edges. Counter flashing is often installed over base flashings to seal joints.

Common materials include aluminum, galvanized steel, copper, zinc, lead, and vinyl or rubber membranes. Material choice depends on climate, exposure, and compatibility with adjacent materials; metals should be corrosion-resistant and properly lapped with end dams to prevent water entry.

Installation requires proper overlaps, sealing at joints, and secure fastening to underlying structures. Counter flashing is used where possible. Proper slope and sealant placement, regular inspection for damage or corrosion, and timely replacement are important. Maintenance and repair should follow local building codes and manufacturer recommendations.