Flashing

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Flashing

What is Flashing?

Flashing, Thin material used to direct water away from building joints and prevent water infiltration

Description

Flashing is thin, impervious material installed at building joints, intersections, and penetrations to direct water away from vulnerable areas and prevent water infiltration into building assemblies. This critical waterproofing component protects buildings from water damage by creating weatherproof barriers at roof edges, wall penetrations, window and door openings, and other locations where different building materials meet.

Purpose includes preventing water infiltration, protecting building materials, directing water drainage, and maintaining building envelope integrity. Quality flashing installation is essential for building protection and preventing costly water damage.

Materials include metal flashing for durability, membrane flashing for flexibility, and composite flashing for specific applications. Material selection affects performance, longevity, and installation requirements.

FAQs

  • What material is best for flashing?

    The best flashing material depends on the application and budget—copper offers maximum longevity, aluminum provides versatility, and membrane flashing works well for complex details.

  • How much should flashing overlap?

    Flashing should typically overlap 4–6 inches depending on exposure and location to ensure proper water shedding and joint protection.

  • Can flashing be repaired or must it be replaced?

    Minor flashing damage can often be repaired with patches or sealants, but extensive deterioration usually requires full replacement for reliable performance.

  • What causes flashing to fail?

    Flashing failures are commonly caused by improper installation, material deterioration, or building movement that breaks water-tight seals.

  • Is flashing required by building codes?

    Yes, building codes require flashing at roof edges, penetrations, wall openings, and other locations vulnerable to water intrusion.

  • How often should flashing be inspected?

    Flashing should be inspected annually and after severe weather events to identify issues before water damage occurs.

  • Can flashing be installed over existing flashing?

    In some cases flashing can be installed over existing materials, but removal is often necessary to ensure proper integration and long-term performance.

Fun Fact

Fun Fact: The ancient Romans used lead flashing over 2,000 years ago to waterproof their buildings, and many of these installations are still functioning today, demonstrating the importance of quality flashing materials.

CSI Code

07 62 00

NAHB Code

72