Dripcap: What It Is and Why Your Home Needs OneA dripcap is a small but important piece of exterior trim that protects windows and doors from water intrusion. Though often overlooked, it plays a crucial role in keeping the building envelope dry and preventing rot, mold, and energy loss. This article explains what a dripcap is, how it works, the types available, how to install one, signs it needs replacement, and when to call a professional.
What is a dripcap?
A dripcap (also spelled drip cap or drip edge in some contexts) is a strip of metal or other rigid material installed over the top of a window or door frame. Its primary function is to divert rainwater away from the head (top) of the opening so that water does not run down into the joint between the window or door and the surrounding wall. By shedding water outward, a dripcap helps to protect the building materials beneath — including flashing, sheathing, and framing — from moisture damage.
Key fact: A dripcap directs water away from window and door heads to prevent infiltration.
How a dripcap works
A dripcap creates a small overhang above the window or door head. When rainwater flows down the exterior wall, the dripcap intercepts it and forces it to drip off the outer edge rather than continuing along the wall surface and into the head joint. Properly flashed and sealed, the dripcap is integrated with the window or door flashing system so water that reaches the dripcap is directed safely to the exterior.
Mechanically, a dripcap usually features a bent or folded profile that provides a sharp drip edge. That sharp edge breaks surface tension and prevents water from clinging to the underside and running back toward the wall.
Common materials and profiles
Dripcaps come in several materials and profiles, chosen based on durability, appearance, and ease of installation:
- Aluminum: Lightweight, rust-resistant, and easy to cut. Common for residential applications.
- Galvanized steel: Strong and more durable than aluminum; requires a painted finish or coating to resist corrosion.
- PVC or composite: Resistant to rot and corrosion; matches some trim styles and is paintable.
- Wood: Traditional option, often used with older homes; must be painted or sealed to prevent rot.
Profiles vary from simple flat flashing with a bent lip to decorative drip mouldings that add an architectural finish. Many prefabricated dripcaps are designed to integrate with window flanges and self-adhesive flashing tapes.
Installation basics
A proper dripcap installation is part of a larger window or door flashing and water-management strategy. Basic steps include:
- Prepare the opening: Ensure the head and jambs are properly flashed, sheathing is in good condition, and any existing trim removed.
- Install head flashing: If using separate head flashing, fit it over the top of the window or door so it extends onto the cladding above.
- Add the dripcap: Position the dripcap so its outer lip overhangs the cladding surface; fasten it above the head flashing or integrated flange per manufacturer instructions.
- Seal and integrate: Use compatible flashing tape and sealants to integrate the dripcap with the window flange and surrounding weather-resistive barrier (WRB), ensuring a continuous drainage plane.
Important details:
- The dripcap must extend past the jambs slightly so water is diverted away from the sides.
- Fasteners should be placed where they won’t penetrate the window’s frame or compromise the WRB; use flashing to cover fastener heads.
- Use corrosion-resistant fasteners appropriate for the selected material.
Dripcap vs. flashing vs. drip edge
These terms are related but distinct:
- Dripcap: Specifically installed over window and door heads to divert water away from the opening.
- Flashing: A broader category of materials (metal, tape, membranes) used to prevent water from entering joints and to direct water out of the wall assembly.
- Drip edge: Usually refers to roof-edge metal that directs water away from fascia and into gutters.
All three are part of a comprehensive water-management strategy for a building.
When a dripcap is especially important
- Older homes with minimal flashing: Many older installations lack modern flashing; adding a dripcap is a cost-effective upgrade.
- Areas with heavy rainfall or wind-driven rain: Extra protection reduces the risk of infiltration.
- Homes with wood siding, stucco, or other claddings that are susceptible to moisture damage.
- New window installations: Ensuring a properly integrated dripcap during installation prevents future problems.
Signs your dripcap needs replacement
- Visible rust, corrosion, or peeling on metal dripcaps.
- Rotting, splitting, or delamination of wood dripcaps.
- Water stains or paint failure beneath the window head.
- Mold, mildew, or interior staining near the top of windows or doors.
- Peeling flashing tape or gaps between the dripcap and cladding.
If you notice repeated leaks or deterioration around multiple openings, check the condition of the dripcaps and flashing across the building.
DIY vs. professional installation
DIY: A competent DIYer can install or replace a dripcap on a straightforward exterior with accessible openings. Common pitfalls include improper integration with the WRB, inadequate overlap, and using incompatible sealants.
Professional: Call a pro if flashing integration is complex, the wall assembly needs repair, openings are large or high up, or you suspect concealed water damage. A contractor can assess the full drainage plane and make sure the dripcap and flashing are installed to last.
Cost and lifespan
- Cost: Individual dripcaps are inexpensive (materials often under \(20–\)50 each for common aluminum or PVC trims), but labor adds up. A professional installation for multiple windows may run several hundred dollars per opening depending on complexity.
- Lifespan: Aluminum and PVC dripcaps can last decades if properly installed; wood requires maintenance and periodic repainting and may need replacement sooner.
Maintenance tips
- Inspect annually, especially after heavy storms.
- Repaint or reseal wooden dripcaps every few years.
- Keep adjacent cladding and caulking in good condition.
- Replace corroded metal dripcaps rather than patching repeatedly.
Conclusion
A dripcap is a simple, low-cost element that provides meaningful protection for windows and doors by directing water away from vulnerable joints. Proper material choice, installation, and integration with flashing and the WRB are essential to its effectiveness. For long-term performance, inspect and maintain dripcaps periodically and consult a professional when water intrusion or structural damage is suspected.
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