A drip cap is a small piece of flashing installed above a window, door, or other horizontal trim element, angled to direct water away from the top of that opening rather than allowing it to run down the wall surface directly above and potentially find its way behind the trim.
This small but important detail addresses a specific vulnerability, since a flat horizontal trim surface without this protective flashing can accumulate water or allow it to work behind the trim over time, particularly during wind-driven rain conditions.
Proper drip cap installation includes adequate slope for effective water shedding and appropriate integration with the surrounding water-resistive barrier and siding to ensure water is directed cleanly away rather than simply redirected to another vulnerable location.
What Does a Drip Cap Involve?
- Angled metal flashing above window and door trim
- Integration with the water-resistive barrier above
- Proper overlap with siding installed above the cap
- Adequate slope for effective water shedding
Why Is a Drip Cap Important?
By directing water away from the vulnerable top edge of window and door trim, a drip cap prevents water from pooling on a flat horizontal surface or working its way behind the trim, a genuine protective function that helps prevent rot and water intrusion at these common problem locations. This modest component provides outsized protection relative to its small size and cost.
Older homes sometimes lack proper drip caps, particularly if original construction predated more rigorous modern flashing standards, making their addition a worthwhile upgrade during any window or trim replacement project even if not originally present.
Drip Cap vs. Window Flashing
A drip cap specifically addresses water shedding above a window or door’s horizontal trim. Window flashing is the broader category covering all flashing needed around a window opening, including the drip cap along with side and sill flashing addressing the opening’s other edges.