Drip Cap

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Drip Cap

What is Drip Cap?

A drip cap is a flashing installed above doors or windows to direct water away and prevent moisture intrusion.

Description

A drip cap is a type of flashing installed above exterior doors, windows, and other wall openings to redirect water away from the building envelope. Its primary function is to prevent rainwater from running behind trim, siding, or cladding, where it could cause moisture damage.

In construction, drip caps are typically made from metal, vinyl, or composite materials and are installed behind siding but over window or door trim. The projecting edge of the drip cap creates a break that causes water to drip clear of the wall surface rather than clinging and migrating inward.

Proper integration of a drip cap with the drainage plane and flashing system is essential for effective water management. Building codes and manufacturer installation guidelines often require drip caps at exterior openings. When installed correctly, drip caps help extend the life of wall assemblies and reduce the risk of rot, mold, and structural deterioration.

FAQs

  • What is a drip cap used for?

    A drip cap directs water away from doors, windows, and openings to prevent moisture intrusion.

  • Where is a drip cap installed?

    It is installed above exterior doors and windows, behind siding and over trim or frames.

  • What materials are drip caps made from?

    Common materials include aluminum, galvanized steel, copper, vinyl, and composite materials.

  • Is a drip cap required by building code?

    Many building codes require flashing, including drip caps, at exterior openings.

  • Can drip caps be installed on existing buildings?

    Yes, drip caps can often be retrofitted, though siding or trim may need to be removed.

Fun Fact

Drip caps work using surface tension—by breaking water’s path, they stop it from clinging to the wall and sneaking inside.

CSI Code

07 62 00

NAHB Code

760