What Is Bulk Water Intrusion?

Bulk water intrusion occurs when liquid water enters a roof system through openings, failed flashing, ice dams, or material damage. Unlike vapor movement, bulk water intrusion introduces moisture rapidly and in large volumes.

RNKC Definition of Bulk Water Intrusion

RNKC defines bulk water intrusion as uncontrolled liquid water entry caused by gravity, wind-driven rain, or surface pooling.

Common Causes

• Roof covering damage
• Flashing failure
• Ice dam formation
• Improper drainage paths

For system-level explanations, visit the ROOFNOW™ Knowledge Center.