Standard building envelope testing and most roofing product warranties assume predominantly vertical precipitation. Real-world summer thunderstorms, particularly supercell events common in the Central US, deliver rain at high horizontal angles, fundamentally changing which building details are at risk.
Vulnerable Details Under Wind-Driven Rain
- Horizontal window head flashings and drip caps
- Through-wall penetrations for pipes and HVAC
- Brick veneer weep holes and cavity wall drainage paths
- Recessed entry soffit and canopy connections
- Parapet coping joints and end dams
Post-Storm Investigation Protocol
Wind-driven rain intrusion often does not manifest as visible damage for days. Water that enters through a window head flashing can travel horizontally through insulation before wetting the interior finish 8 to 10 feet from the actual entry point. Thermal imaging post-storm is the most reliable detection method.
Temporary Sealing as an Immediate Response
When wind-driven rain intrusion is identified, temporary sealing of vulnerable details with compatible tape products and shrink wrap is an effective immediate response while the permanent repair scope is being defined.
