Static field route #19614

What do I do when siding or plywood blocks the back of a fresh-air intake louver?

Equipment Connections: RTU, AHU, VAV, Fans & Louvers🛑 STOP / GET DIRECTIONField answer expansion

📖 Verified core answer

A louver needs an open air path behind it. If another trade covers the opening, stop the cover-up and get the obstruction removed or redesigned before startup.

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Field verification checklist

Look through the louver and confirm the back side is open.
Check whether the bird screen is pressed against plywood, paneling, or cladding.
Confirm the active louver area from the mechanical drawing/submittal.
Photograph the blocked condition before anyone hides it.
Hold startup until the opening is cleared and protected.

Ask foreman

The intake louver at [location] is blocked behind the bird screen by [material/trade]. I verified the face is not open to the plenum. Do you want this held for the GC/siding crew to cut the opening clear?

Text to foreman

Route options

A Correct it only if the fix is within your assignment and approved method.

B Hold and document if it affects water intrusion, weatherproofing, rated assemblies, structural anchorage, controls, TAB, or another trade.

C Bring the foreman/detailer the location, what you checked, and what decision you need before sealing, testing, cover, or startup.

Do not do this

Do not assume an exterior louver is functional just because the face looks installed.

Why this matters

A blocked intake can starve equipment, create building pressure problems, and damage the louver or fan.

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, pressure/material schedule, and AHJ/code requirements.

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