Window head flashing is one of the most important elements of water management in wall assemblies. This article explains how to integrate flashing and drip caps at window and door heads to prevent water intrusion and preserve control layer continuity.
Purpose of Head Flashing and Drip Caps
Head flashing is designed to collect and divert water that reaches the wall assembly above windows and doors. When installed properly, it prevents water from draining directly onto fenestration units, limiting potential infiltration and protecting surrounding materials from deterioration.
Flashing Integration Techniques
- Install metal head flashing or drip cap with a hemmed drip edge extending at least 1″ beyond window frame
- Integrate with self-adhered flashing tape, extending 6″ past the unit on each side
- Lap WRB membrane over top leg of metal flashing and seal edges with flashing tape or liquid membrane
- Use foam back dam or pan flashing below window to complete the drainage path
Installation Tips and Common Mistakes
- Do not install flashing behind cladding or WRB without overlap or seal
- Avoid flat or inward-sloping drip caps—always slope to drain
- Ensure foam back dams are continuous and not compressed by fasteners
- Do not use caulk as the primary water barrier—rely on proper lapping and membrane sealing
Mockups should include full head and jamb flashing with WRB integration, reviewed prior to siding or masonry install.
Disclosure: As an Amazon Associate, EnvelopeIQ earns from qualifying purchases.
