Headwall flashing is installed where a roof surface meets a vertical wall from below, at the top edge of a roof plane running into that wall, directing water away from the wall-roof junction and preventing it from running behind the wall covering at this specific transition.
This condition differs from a sidewall situation addressed by step flashing, since headwall flashing deals with the roof’s upper edge meeting a wall, rather than the roof’s slope running parallel alongside a wall.
Proper headwall flashing installation typically involves integrating the flashing beneath the wall covering above while extending it out over the roofing material below, creating a layered barrier against water intrusion at this junction.
What Does Headwall Flashing Involve?
- Metal flashing extending from the wall out over the roof
- Integration beneath the wall covering above the flashing
- A kickout diverter at the point where the wall meets a gutter, if applicable
- Careful sealing at the transition to prevent water intrusion
Why Is Headwall Flashing Important?
Without properly installed headwall flashing, water running down the wall above can flow directly onto the roof edge or behind the roofing material rather than being directed cleanly onto the roof surface and toward the gutter system, creating a persistent leak risk at this junction. This condition often occurs where a second story wall meets a lower roof section, like above a garage or porch addition, making proper flashing here particularly important on homes with this common architectural configuration.
A missing or inadequate kickout diverter at the bottom of a headwall condition, where the wall-roof junction meets a gutter, is a well-documented cause of water damage to the wall and framing just below that point, since water can otherwise run behind the gutter rather than into it.
Headwall Flashing vs. Kickout Flashing
Headwall flashing addresses the general condition where a roof meets a wall from below. Kickout flashing is a specific component at the bottom of that junction, diverting water into the gutter rather than letting it run behind it at that critical termination point.