Static field route #19104

What do I do when a multi-section louver leaks at the vertical mullion joint?

Equipment Connections: RTU, AHU, VAV, Fans & Louvers⚠️ CHECK BEFORE YOU FIXV191 answer-gap expansion

📖 Verified core answer

Multi-section louvers need the approved splice, gutter, sealant, and weep path. Do not rely on face caulk only when water is entering through the mullion joint.

Open in Field Rescue Open category

Field verification checklist

Water-test or trace the leak path at the vertical joint.
Check manufacturer splice/mullion detail and weep path.
Inspect missing internal gutter/splice channel, failed sealant, or blocked weeps.
Coordinate with façade/waterproofing trade before exterior face caulking.
Retest after repair.

Ask foreman

The multi-section louver at [location] is leaking down the vertical joint. I checked the mullion/splice and weep path. Do you want the internal splice/gutter detail corrected before more face sealant?

Text to foreman

Route options

AMake the field correction only if it is within your assignment and the approved method.

BHold and document the condition if the fix affects airflow, access, life safety, pressure class, rated assemblies, equipment, or another trade.

CBring the foreman/detailer the location, what you checked, and what decision you need before cover, startup, or rework.

Do not do this

Do not smear silicone over the exterior face and ignore the internal water management path.

Why this matters

Bad louver joints can leak into walls, fan rooms, ceilings, and finished spaces long after punch.

Final verification

Use this as field training guidance. Final direction still comes from the foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, and AHJ/code requirements.

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